Space Marines

The Space Marines or Adeptus Astarte's are foremost amongst the defenders of humanity , the greatest of the Emperor of Mankind's warriors. They are barely human at all, but superhuman; having been made superior in all respects to a normal man by a harsh regime of genetic modification, psycho-conditioning and rigorous training. Space Marines are untouched by plague or any natural disease and can suffer wounds that would kill a lesser being several times over, and live to fight again. Clad in ancient Power armour and wielding the most potent weapons known to Man, the Space Marines are terrifying foes and their devotion to the Emperor and the Imperium of Mankind is unyielding. They are the God-Emperor's Angels of Death, and they know no fear.The Astartes are physically stronger, far more resilient and often mentally far removed from the lot of most normal human beings. In the presence of the Astartes, most people feel a combination of awe and fear, and many cultures on the more primitive worlds simply worship them outright as demigods or angels of the God-Emperor made flesh. They should feel so, for many Space Marines feel little compassion for those they have sometimes termed "mortals" in comparison to themselves, seeing the very people they were created to protect as little more than obstacles to a more efficient eradication of the Imperium's enemies. This is an attitude sometimes taken by whole Chapters. They see normal humans as frail, weak creatures given to the follies of temptation, avarice, greed, lust and cowardice -- all emotions they rarely feel, if ever. Yet there are some Astartes who remember why they were created by the Emperor, who avoid the trap of hubris which the Space Marines are so prone to and which has seduced so many of their number to serve the Ruinous Powers. They are the final guardians of Mankind, the saviours of last resort. They were intended not to lead humanity, but to defend it, sometimes even from itself. At the heart of that mission lies the limitless compassion the Emperor extended to every man and woman in the galaxy when he willingly chose to condemn himself to more than 10,000 years of imprisonment within a dying prison of flesh for their sake. Some Astartes sneer at compassion, seeing it as one more human weakness that has been purged from their superior bodies and minds. But the wisest of the Space Marines know that in the end compassion is their only salvation, as it is for all men. In that, they have proven themselves to be fully human.
Potential Space Marines are usually, but not always, recruited from the worlds where a Chapter has established its fortress-monastery, although some Chapters are known to recruit from a collection of different worlds in an area of space that they protect or frequent. Recruiting methods vary from Chapter to Chapter. Some select their Neophytes from feral tribes roaming the surface of inhospitable worlds, while others draw upon eager volunteers who have been groomed from birth to become an Astartes. Still others watch and kidnap potential warriors, turning them into Astartes whether they will it or not. Whatever the method, all Space Marine Chapters will only accept those who successfully pass the grueling initiation trials and prove themselves worthy of becoming a Space Marine. 
However a man becomes a Space Marine does not matter: once his body has been forged into that of a transhuman Astartes, he must forever stand apart from the people to whom he was once kin and who he is now sworn to protect. Once a man becomes a Space Marine, he is no longer mortal; his genetic heritage is now that of the Emperor design, and a spark of the same divine majesty flows in his veins. 
There are approximately 1,000 Space Marine Chapters active in the Imperium of Man at any one time. This number has stayed relatively constant since the Second Founding in the 31st Millennium following the Horus Heresy when the First Founding Space Marine Legions of 50,000- 250000 Space Marines were broken up. However, this number remains far from exact and may fluctuate widely depending on the time period and the circumstances confronting the Imperium. 
== History ==
=== Origins ===
The Space Marines are the Imperium of Man’s supreme warriors. Genetically-enhanced to be the ultimate soldiers of Mankind, they are far stronger and more resilient than ordinary human beings. Space Marines are organised into roughly a thousand Chapters, with each Chapter numbering approximately 1000 warriors organised into ten companies of 100 troops each. Each Chapter is a self-sufficient Imperial army, equipped with its own spacecraft and capable of responding at a moment’s notice to any threat to the security of the Imperium. Every Chapter is fiercely proud of its history and achievements, and each one has its own distinctive colours and heraldic markings. These were established at the Chapter’s Founding and are displayed with pride upon all of its armour and vehicles. All of the wargear of the Space Marines is painstakingly maintained, and many items are covered in lines of intricately rendered devotional script in High Gothic, each line detailing a battle honour won in a glorious campaign. A Space Marine is a towering warrior, his brute strength tempered by inhuman skill. He is armed with the fearsome Bolter, a blessed weapon that fires devastating, mass-reactive shells that explode within the flesh of the target. He is protected by a suit of Power Armour, shielding him from the fiercest of enemy fire whilst simultaneously strengthening his blows and allowing him to survive the most hostile of environments. He is the product of intensive training and genetic manipulation, which transforms mortal men selected from the deadliest warrior races in the known galaxy into the most lethal of superhuman killing machines in Mankind's arsenal.
=== The Thunder Warriors ===
The Space Marines can trace their origins back to the Unification Wars on Terra in the late 30th Millennium, when the Emperor of Mankind first revealed his existence and lead regiments of deadly genetically-engineered soldiers known as Thunder Warriors in a great campaign to unite all of the myriad techno-barbarian tribes and nation-states of Terra under his rule. From the outset of his retaking of Terra, the Emperor employed genetically modified warriors within his forces and in these early enhanced troops lay the origins of what would later become the Space Marine Legions. During the Age of Strife, known as "Old Night" on Terra, the cradle of Mankind had seen more than its fair share of augments and "super" soldiers created both from bio-alchemy and cybernetic augmentation. But it was the Emperor's own Thunder Warriors, named for the early thunderbolt and raptor's head heraldry used by their master in the Imperium's earliest days, that were to prove superior to all of them. These superhuman warriors were a gestalt mix of unprecedented superhuman physical power, gene-programmed resistance to environmental and even psychic attack, a warlike spirit and the Emperor's own strategic genius. The Thunder Regiments were an army unlike any that had come before them, and the forces of the powerful tyrants of Old Earth had nothing to match them.
This Unification of humanity's homeworld marked the beginning of the Imperium of Man and the Emperor's quest to reunite all of humanity under a single interstellar government. This quest was intended to prevent his race's extinction from the growing threats which confronted the human-settled galaxy in the wake of the Age of Strife. But despite their many early victories in the Unification Wars, the Thunder Warriors were far from perfect. Some were mentally unstable, others suffered catastrophic biological failure after an unprecedented span of years as their own superhuman physiques turning against them in the end. It seems obvious in retrospect that the Emperor knew early on that a more permanent and stable force of enhanced warriors was needed, so even while the Thunder Warriors waged war in their early days the Emperor gathered about him a team of savants and gene-wrights, some willing and others as captives taken from his foes, and constructed new genetics laboratories deep in the vast dungeons of his Terran fortress beneath the Himalazian (Himalayan) Mountains. Labour there went on for decades in absolute secrecy and resulted in the creation of the Primarchs and other wonders of gene-craft known and unknown. Data does not back up this statement but some guards of the Emperor have been on record stating that a young child was involved in the labour that commenced. Foremost amongst these were the Space Marine Legions, the Legiones Astartes. Into their creation went all the secret history and genetic lore of the Age of Strife, hard wisdom gained through the success and failure of the Thunder Warriors and the Emperor's own inimitable genius.
=== The Grey Legions ===
The first among the Space Marines were hand-picked men drawn from the Emperor's personal bodyguard. These volunteers were subjected to surgical, genetic and psychological modification. With rigorous training and appropriate mental conditioning they became not only immensely strong and tough, but iron-willed and disciplined, an unstoppable force whose loyalty to the Emperor was unflinching. Quickly the process was refined and systematised, and the numbers of the new enhanced warriors, at first armed and armoured as the Thunder Warriors had been, grew swiftly. The first Astartes were organised into twenty distinct regiments numbering no more than a few hundred warriors each. Although it remained a dire secret at the time, it is now widely believed that this division was more than a merely administrative one, as each regiment contained variant gene-seed encoding drawn from a different primogenitor Primarch. This often manifested its influence in subtle and unexpected ways, not least of all in influencing the psychological character of the genetically enhanced warriors. With the regiments expanding rapidly into full Legions with the intake of new blood from the areas of Terra that had already joined cause with the Emperor, the new warriors quickly eclipsed and replaced the mighty but far less disciplined and unstable Thunder Warriors. As the Space Marine Legions were unleashed in the latter days of the Unification Wars, victory followed victory in quick succession.
CHECKED UP TO HERE
As time went on, the Space Marine regiments became Legions as the Emperor recruited men from amongst the newly conquered tribes of Old Earth and the hundreds of Astartes in service to the Imperium swiftly became tens of thousands. These superhuman troops dominated the Wars of Unification, easily defeating all their Terran opponents and forcing the of who had intervened in the conflict on Terra to sue for peace. The Space Marines fought with righteous zeal and it was they who first referred to their mission as a "Crusade." By their efforts, for the first time in unrecorded millennia, the Earth was united under the rule of one man. The armour they wore was not new, but the same partially powered armour that had evolved on Old Earth and was worn by the elite of both the Emperor's armies and the techno-barbarian tribes that had fought against him. Some of this "Thunder Armour," first named for the Thunder Regiments that were the Legions' forebears, was newly forged, but the Emperor's warsmiths also took or cannibalised many suits from the armouries and corpses of conquered foes. As if to mark a break from the wars of the past, the armour of the first Astartes was cast in storm cloud grey, and bore only the thunderbolt and lightning marks of Imperial Unity. Over time, the Space Marine Legions gained their own marks of distinction and character. Names, Emperor-given in some cases, others by the Primarchs, came to replace the Legions' original numbers, with many Space Marines companies seeking to single themselves out from their brother Legions. Battle honours were accumulated and the effect of each Legion's character worked upon them, so that as the Legions expanded to conquer the galaxy, storm cloud grey became granite, silver, viridian, sable, gold, ocean, ash or ice, and by the time of the , the "Grey Legions" of the Unity era were gone, lost to history. 
=== The Primarchs ===
Of the 1,000 or more Space Marine Chapters thought to be in existence at the present time, a blessed few can trace their beginnings back to an age more than ten thousand standard years ago in the late 30th Millennium, when the blessed Emperor of Mankind still walked amongst mortals. In those days, the Emperor first created the Primarchs, 20 immortal superhumans blessed with extraordinary intelligence, charisma and sheer physical might who were to be his generals and closest comrades during the Great Crusade to reunite the scattered and long-isolated human colony worlds after the end of the Age of Strife. The Primarchs wielded powers the like of which are not known in the Imperium today, yet they were lost to the Warp in an accident deep within the Emperor's gene-laboratories beneath the fortress that would become the Imperial Palace and were scattered, still in their gestation capsules, to worlds across the galaxy by the will of the Dark Gods of Chaos. The first Space Marines of the nascent Imperium were also the creation of that era, each made using the genetic inheritance of one of the Primarchs, albeit diluted a hundred times, for no merely human body could contain such power. As each of the Primarchs were encountered in turn by Imperial Expeditionary Fleets during the progress of the Great Crusade, they became the natural and obvious leader of the Space Marine Legion created from their genetic material and with whom they had so much in common. In many cases the Primarch's adopted world became the new base of operations for their Legion and was known henceforth as that Legion's homeworld. The Primarchs then recruited their loyal followers from each of these world's peoples into the ranks of their Legion while others were given rights to draw fresh blood from suitable warlike worlds that were liberated as the Great Crusade progressed. 
With the re-discovery of the Primarchs and in many cases newly adopted homeworlds used as Legion fiefs (most commonly the worlds upon which a Legion's new master had been found), this was to change the character of the Legions profoundly. Some alterations were superficial: a habit of speech, a change in close-quarter tactics, martial traditions and warranted additions to iconography and even language. But for others the change would prove dramatic, with entire paradigms of culture, tradition and even ideology overwriting what had come before, such as in what came to be known as the Space Wolves and Dark Angels Legions. In many cases the stamp of the Legions and the will of the Primarchs on their recruits came to largely outweigh differences of birth or blood, but in other Legions such as the Luna Wolves and the Emperor's Children, a subtle divide would grow between those veterans who had been recruited into the ranks of the Astartes by the Emperor from Terra and those who had come into the Legion from their Primarch's homeworld. This rift would be one factor among many that would lead several of the First Founding Legions towards ultimate damnation. 
The names of many of the Primarchs still echo down the millennia, and the tales of their deeds are legendary. Names such as Lion El'Jonson, Leman Russ, Rogal Dorn, Vulkan, Corax and the angel-winged Sanguinius are spoken of with awe on those worlds where Mankind dwells. They command a reverence second only to that afforded the Emperor Himself. Other names are cursed wherever men gather, for many of the Primarchs rebelled against the Emperor and followed Horus, mightiest of their number, when he raised his standard against Mankind on behalf of Chaos.
=== Crusade and Expansion ===
As the Great Crusade continued the expansion of the nascent Imperium into the galaxy, the discovery of the Primarchs and their newly adopted homeworlds helped to stem an impending crisis that was not widely known of at the time outside of the exalted ranks of the Imperium's ruling : namely, the diminishing stability of the gene-seed itself through over-use and the increasing need for ever greater numbers of Space Marines in the field. This was a matter that only worsened as the Great Crusade pushed ever wider afield into the galaxy. Imperial forces could no longer be concentrated as easily as before, and attrition was taking its toll as years of near-constant battle became decades. To relent the pace of the Great Crusade's progress was for the Emperor simply not an option and so the simple truth was that more Space Marines were needed and they needed to be created faster than before.
A secret conclave of gene-wrights under the Emperor's direct supervision posited the solution that became known as , which demonstrated that a Primarch's genetic code could be used to stabilise and expand Astartes gene-seed stocks with what was hoped to be "minimal deviation." Alongside this accelerated gene-culturing technique, other previously unavailable genetic technologies were put into effect, reducing the processing time required to create a battle-worthy Space Marine to a single Terran year in some cases. Such accelerated gene-seed techniques, along with absent, inadequate or over-forceful psycho-doctrination techniques, were later found to have unseen fundamental flaws. Many Imperial savants since have come to believe that the drive to create larger Space Marine Legions at accelerated speed played a prime role in the degradation of the sanity and psychological make-up of certain Legions and paved the way for the horror that was to come. 
=== Horus Heresy ===
At the very height of the Emperor’s Great Crusade, the traitorous Warmaster Horus led his Traitor Legions of Chaos Space Marines against those who stood loyal at the Emperor’s side. Hundreds of worlds burned in the name of the Dark Gods, and a terror unlike any seen before was unleashed across the galaxy during the seven dark standard years that the Heresy raged. Much of the truth of these times has been lost, obscured by the mists of time or embellished to the point where giants bestrode worlds with thunderous steps and the planets themselves cracked and split at their tread. The Traitor forces of Horus drove all before them, until those Astartes Legions still loyal to the Master of Mankind stood at bay upon the fortified walls of the Imperial Palace during the climactic Battle of Terra. The forces of darkness pressed in around the guttering flame of humanity, but desperate times called for desperate solutions. Sanguinius of the Blood Angels and Rogal Dorn of the Imperial Fists, together with their bravest warriors, would accompany the Emperor and take the fight to Horus upon his Battle Barge the Vengeful Spirit, a mighty warship in orbit above Terra.
The Emperor and his warriors teleported onto Horus' Battle Barge but found themselves separated and scattered throughout the corrupt vessel by means of the Warmaster's dark sorcery. The Emperor fought his way to the Warmaster but was too late to save Sanguinius, who Horus slew when the angelic Primarch refused to turn to Chaos. Yet, some maintain that Sanguinius inflicted a wound, however small, upon his erstwhile brother. Horus and the Emperor clashed in a battle of both flesh and spirit. Horus was filled with the power of the Ruinous Powers and dealt the Emperor a mortal blow, but in the end, the Emperor's will was the greater, and Horus was struck down with the last ounce of the Emperor's strength. The traitor was destroyed utterly, in body and soul and, with his death, the power of the Traitor Legions was broken. When Dorn and his warriors finally fought their way into the rebel Warmaster’s sanctum, they found the Emperor’s broken and ruined body, and it is said that their cries of woe were heard far below on Terra itself. Rogal Dorn, most determined and unbending of the Primarchs, bore his master's body back to Terra and, under the direction of the crippled Emperor, bound him within the strange psychic augmentation device known as the Golden Throne to sustain his existence for all eternity with constant sacrifice and baroque machineries. The followers of the Ruinous Powers were defeated, but it was victory won at a terrible cost. The brotherhood of the Primarchs was sundered, and the Emperor's vision for the Imperium and all of Mankind lay in ruins—the last, best hope of its fulfillment lost forever. 
The galactic empire for humanity the Emperor had forged was all but destroyed, and it was to take many more years of brutal warfare during the Great Scouring before all the Traitor forces were defeated and driven into the hellish chaos of the Eye of Terror. The death toll numbered in the billions, and uncounted worlds had been left as little more than corpse-haunted wastelands as the raging inferno of the Horus Heresy was finally extinguished, though Mankind still teetered on the very brink of extinction. The Heresy had revealed weaknesses in the gene-seed of several of the early Space Marine Legions, which had been exacerbated by the need to keep the huge formations up to strength in the terrible wars being fought during the Great Crusade. The insidious powers of Chaos had been able to manipulate this corruption to turn Horus and many of the Space Marines under his command against the Emperor. 
Once Horus was defeated, it was decided that the forces of the Imperium would be reorganised so that a similar catastrophe could not be repeated. The Space Marine Legions were divided up to create one Chapter of the same name as the founding Legion and a number of new Chapters with new names. This critical event of the early 31st Millennium was called the Second Founding, and over two dozen further Foundings have occurred in the ten millennia since. It is not known exactly how many Chapters were created in the aftermath of the Horus Heresy, as many of the Imperium’s records are incomplete or lost entirely, and whole Chapters have been created and destroyed in the millennia that have followed. What is known is that there are just over a thousand Chapters scattered across the Imperium, each a brotherhood of the very finest warriors humanity has ever called to its service.
=== The Codex Astartes ===
In the wake of the calamity that was the Horus Heresy, the foundations of the present-day Imperium were laid down. The first High Lords of Terra established the structure by which the Adeptus Terra operated, and described the feudal responsibilities and duties of the Planetary Governors. One of the most important accomplishments was the reorganisation of the Imperium's military forces. This was undertaken almost single-handedly by the Primarch of the Ultramarines Legion, Roboute Guilliman, who with his characteristic speed and efficiency codified the structure of the Astra Militarum, the Imperial Navy, and the Space Marines. Of all of his works, the most influential is the Codex Astartes, the great prescriptive tome that lays down the basic organisational and tactical rules for a Space Marine Chapter. The Codex Astartes decreed that Space Marines would be created and trained over a controlled period of time.
With the threat of the Traitor Legions held at bay in the wake of the Horus Heresy and the Great Scouring, Roboute Guilliman turned to ensuring that such a catastrophe could never happen again, distilling his formidable wisdom into a mighty tome known as the Codex Astartes. This text became a major part of his legacy and the cornerstone upon which the future of the Imperium would be based. 
Of special interest is the volume of the Codex devoted to the Adeptus Astartes, describing in detail the tactical roles, equipment specifications, uniform markings, command protocols and countless other aspects of Space Marine doctrine. Though for all its multitudinous topics, the most lasting and contentious decree of the Codex Astartes was that the existing Space Marine Legions be broken up and reorganised into smaller organisations known as Chapters. Though many of his brother Primarchs initially railed against Guilliman's decree, almost all eventually accepted the necessity of reorganisation for the security of the Imperium. Thus were the Chapters of the Adeptus Astartes born. 
Upon the Codex's implementation, in an event that would become known as the Second Founding, each of the old Legions became a Chapter named for its forebear plus a number of other new Chapters. In addition to a name and heraldry of their own, each of these new Chapters would take for itself a homeworld or fortress-monastery, and use it as a bastion from which to defend the Imperium from all threats. The Codex Astartes stated that each Chapter would be one thousand Battle-Brothers strong and look to its own recruitment, training and equipment. Never again would one man be able to command the awesome, terrifying power of a Space Marine Legion. 
The Horus Heresy had also revealed weaknesses in the gene-seed of several Space Marine Legions. These defects had been exacerbated by the accelerated gene-seed cultivation techniques needed to keep the huge Space Marine Legions up to strength. Guilliman believed that the Chaos powers were able to exploit the resultant physical and mental corruption to turn Horus' troops against the Emperor. One of the key objectives of the new Codex Astartes was to recognise and expunge these genetic weaknesses. As a result, the Codex Astartes decreed that Space Marines would forever more be created and trained slowly. The genetic banks used to create Astartes implants would be carefully monitored and scrutinised for any defects. Cultivated organs would be subject to the most stringent tests of purity. Young Initiates would undergo trials of suitability before they were accepted, and only those of the very sternest character would be chosen. 
As a final safeguard, Guilliman tasked the Adeptus Terra on Earth with setting up and maintaining genetic banks to produce and store tithes of Space Marine gene-seed. These banks were to provide all new gene-seed for subsequent Foundings of Space Marine Chapters. To prevent cross-contamination, the genetic stock of each Legion was isolated whilst that of the Traitor Legions was placed under a time-locked stasis seal, though at the time many believed they had been destroyed. By taking direct control of these genetic tithes, the Adeptus Terra could ultimately control the Space Marines. They alone had the power to destroy or create Space Marine armies at will. 
The genetic banks used to cultivate the organ implants that turn a normal man into a mighty Astartes would be carefully monitored, and cultivated organs would be subject to the most stringent tests of genetic purity. Young Initiates would undergo rigorous trials of physical and psychological suitability before they were accepted, and only those of the highest calibre would be chosen. On Terra, the Adeptus Terra created genetic repositories to produce and store Space Marine gene-seed. These banks were used to provide new gene-seed for the creation of new Space Marines and, to prevent cross-contamination, the genetic material of each of the old Legions was isolated. Henceforth, the new Space Marine Chapters would receive gene-seed only from their own genetic stock. The suspect gene-seed of the Traitor Legions was placed under a time-locked stasis seal, although at the time, many believed these dangerous stocks of tainted genetic material had been destroyed. By taking direct control of their genetic stocks, the Tech-priests of the Adeptus Mechanicus could ultimately control the Space Marines. Now they alone had the power to destroy or create Space Marine Chapters at will. 
Over the millennia, there have been many subsequent Foundings of Space Marine Chapters. Those Chapters that adhere rigidly to Guilliman's teachings are sometimes referred to as "Codex Chapters." These Space Marines pride themselves on following the tenets within the hallowed pages of the Codex Astartes and applying its principles of warcraft and devotion to the Emperor. 
With the passage of centuries, some Chapters have strayed from the strict letter of the Codex, introducing unique variations on its teachings but remaining broadly faithful to Guilliman's basic principles. Furthermore, the Codex has been reanalysed, reinterpreted and modified countless times over the centuries. Indeed, the Codex Astartes of the late 41st Millennium is a highly developed treatise combining the experiences of hundreds of celebrated military thinkers throughout history. Regardless, the Codex Astartes remains, as it has always been, the Space Marines' authoritative guide to waging war. As such, it is revered by every Battle-Brother as a holy text; the wisdom of the ancients serving as both scripture and the unbending rod by which they are measured. 
Most Chapters stick rigidly to the organisation laid down by the Codex Astartes for tactical roles and other processes. Others, such as the Blood Angels, Black Templars and Dark Angels, are organised according to general Codex doctrines but maintain troops, tactics and idiosyncratic traditions that set them apart from their brethren. A small number of Chapters are utterly different from the Codex, and owe nothing to it at all. The most famous of these is the Space Wolves. The sons of Leman Russ have never followed the Codex Astartes -- their strong-willed Primarch moulded his Chapter very much in his own image, irrespective of other influences and dictates. 
The Second Founding 
The Second Founding of the Space Marines was decreed seven years after the death of Horus. The existing Space Marine Legions were broken down and re-founded as smaller, more flexible formations. Where the old Legions were unlimited in size, the new formations were fixed at approximately one thousand Astartes. This corresponded to the existing Astartes unit within some Legions called the Chapter, and in future the Chapter was recognised as the standard autonomous Space Marine formation. No longer would one man have power over a force as powerful as a Space Marine Legion. The existing Space Marine Legions were divided into new Chapters. One Chapter kept the name, badge and colours of the original Legion, while the remaining Chapters took on new titles, badges and colours. Most of the old Legions were divided into fewer than five Chapters, but the Ultramarines, being by far the largest of the Legions, were divided many times. The exact number of new Chapters created from the Ultramarines is uncertain: the number listed in the oldest known copy of the Codex Astartes (the so-called Apocrypha of Skaros) gives the total as 23, but does not name them. 
As a result of the Second Founding, the Ultramarines’ gene-seed became the favoured genetic stock of most subsequent Astartes Foundings. The new Chapters created from the Ultramarines are often referred to as the Primogenitors, or the "first born." All of the Primogenitor Chapters venerate Roboute Guilliman as their founding father and patron. The Codex Astartes further defines the tactical roles, equipment specifications, and uniform identification markings of the Space Marines. These guidelines have evolved over the centuries, and the Codex Astartes of the 41st Millennium is a highly developed treatise combining the wisdom of hundreds of military thinkers throughout history. Some of its contents seem petty and restrictive, hardly worthy of the great mind of a Primarch. Others describe actual battles together with comments on the tactics employed and the decisions of the commanders of the day. As such, the Codex Astartes is revered as a holy text of the Imperial Cult, and many Chapters regard its recommendations as sanctified by the Emperor himself. 
The Chapters that rigidly follow the word of the Codex Astartes are sometimes referred to as Codex Chapters or Codex Astartes-compliant Chapters. These Space Marines adhere to the Codex as the model for their organisation, identification markings and tactical doctrine. Of all of the Codex Chapters, the most famous is the Ultramarines, the Chapter of Roboute Guilliman himself. Most Chapters, however, do not adhere so rigidly to the Codex patterns laid down for organisation, tactical roles, or other processes. Many Chapters are organised largely according to the Codex, but are further shaped by their homeworld and the personality of their Primarch. The Blood Angels and Dark Angels are prime examples of this. A small number of Chapters are vastly different from the Codex, and owe little or nothing to its prescriptions at all. The most famous of these non-Codex Chapters are the Space Wolves, whose strong-willed Primarch Leman Russ moulded his Chapter very much in his own image, irrespective of other influences. The Adeptus Terra has never decreed it necessary to enforce the Codex absolutely. Indeed, it is doubtful whether it could if it so chose. However, with subsequent Foundings, they have always favoured the Ultramarines’ gene-seed and created many new Codex Chapters from that genetic line. With the passage of time, some of these Chapters have subsequently strayed from the strict letter of the Codex, introducing new variations on their organisation or tactical doctrine but remaining broadly faithful to the principles laid down by Roboute Guilliman many millennia before. 
The history of the Imperium since the Horus Heresy is not a continuous story. There have been periods of rebellion and anarchy, times when the balance of power has suddenly changed and history has quite literally been rewritten. Many of the subsequent Foundings of Space Marine Chapters belong to these troubled times, making it almost impossible to ascertain when some Chapters have been created. It is believed that of the one thousand or more Chapters thought to be in existence today, more than half are descended from the Ultramarines, either directly or through one of their Primogenitor Chapters of the Second Founding. It is not known how many new Chapters were created by the Second Founding. Many records were lost during the Age of Apostasy, a troubled time in the 36th Millennium that bestrides the history of the Imperium like an impenetrable wall. In all likelihood, some of the Chapters created during the Second Founding have since been destroyed, leaving no records of the deeds. 
Others have been lost in more recent times, and their names are now all that remains of them. Each of the Chapters into which the Legiones Astartes were subdivided consisted of roughly 1,000 warriors. A large section of the Codex Astartes is dedicated to structuring the organisation of these Chapters. A Chapter consists of ten companies each numbering 100 Space Marines. The warriors of these companies are organised into 10 squads of 10 Astartes led by a Sergeant. In addition to this basic fighting unit, each company has its own Captain, Standard Bearer, Chaplain, and Apothecary. Every company, with the exception of the Scout Company, maintains a pool of Rhino transports for its squads and officers. The elite 1st Company is also equipped with Land Raider tanks to carry heavily-armoured Terminator Squads. It is customary for Dreadnoughts to remain with their company, as their fearsome presence bolsters the company’s fighting strength. 
=== A Thousand Chapters ===
On many occasions in the Imperium's history, there have been long periods of rebellion and anarchy; times when the balance of power has suddenly changed and history been lost or re-written. Many later Foundings of Space Marines were born of such troubled times, making it impossible to ascertain when they were created, their origins ever shrouded in mystery. All that is known for sure is that there are approximately a thousand Chapters of the Adeptus Astartes today -- perhaps less than one Space Marine for every planet in the Imperium. That the Space Marines are equal to the task of safeguarding Mankind against such impossible odds is testament to their dedication and skill in battle. 
It can be said that there are three main categories of Space Marine Chapters. The first and largest group are the scions of Guilliman –- those Chapters descended from the Ultramarines and their Primogenitors. The Primogenitors are those Chapters created when the old Ultramarines Legion was divided during the Second Founding. Sometimes referred to as the "first born," these Chapters each maintain their own histories and traditions, but they all honour Roboute Guilliman as their Primarch and adhere strictly to the procedures and tactical treatises he laid down in the Codex Astartes. There are conflicting records as to exactly how many Primogenitor Chapters were created, but the oldest copy of the Codex Astartes lists twelve. It is believed that there were a further eleven or more Primogenitors, but if they existed, their names have been lost to the passing of time, and no Space Marine Chapter surviving in the 41st Millennium claims the honour. These Chapters maintain their own traditions, for the Codex Astartes insists that each should have its own name, badge and heraldry. Nonetheless, they honour Roboute Guilliman as their Primarch and his successor, the ruler of Ultramar, as their distant liege. Should the Lord of Ultramar ever need aid, he will find these Chapters ever willing to fight at his side. 
The Chapters in the second largest category owe their genetic inheritance to another Primarch, but follow the Codex Astartes as closely as their divergent genetic heritage allows. While primarily made up of successor Chapters, such as the Crimson Fists and Brazen Claws, this group also includes several Chapters from the First Founding –- most notably the White Scars, Imperial Fists, Iron Hands and Raven Guard. While they still venerate their own Primarchs, they nevertheless also aspire to the high standards and wise teachings that Roboute Guilliman put down in the Codex Astartes. 
The final group is more wildly aberrant. These Chapters, by virtue of a gene-seed quirk, the teachings of their own Primarch, or even sheer stubbornness, eschew the Codex Astartes in favour of their own structural and combat doctrines. The Black Templars and Space Wolves are amongst this group, remaining fiercely independent and looking to their own divergent beliefs and ways of war.
=== The Chronicle of Heroes ===
* The Horus Heresy (ca.006-014.M41) - The Imperium is torn apart by the Horus Heresy, the great interstellar civil war fought between the Loyalist and Traitor Space Marine Legions. The rebel Warmaster Horus, despite pledging himself and his followers to the service of Chaos is defeated in single combat aboard his flagship Vengeful Spirit by the Emperor of Mankind at the conclusion of the Battle of Terra. Though Horus is slain, the Emperor is mortally wounded and must be placed within the arcane mechanisms of the device known as the Golden Throne. No longer able to interact directly on a day-to-day basis with Mankind, the Imperium is reorganised under the direction of the Primarch Roboute Guilliman as the Lord Commander of the Imperium and the other great lords of the Senatorum Imperialis. 
* The Great Scouring (ca.014-021.M31) - The Loyalist Space Marine Legions, in the course of their separation and the Imperial Army succeed in driving the Traitor Legions from their remaining holdings in the galaxy, and force them to flee into the eternal Warp rift known as the Eye of Terror in the Segmentum Obscurus. The remaining nine Loyalist Space Marine Legions are subjected to the Second Founding and the organisational dictates of the Codex Astartes, resulting in the creation of approximately 1,000 individual Space Marine Chapters. The Imperial Army is divided into the separate services of the Astra Militarum (Imperial Guard) and the Imperial Navy. The newborn Astra Militarum replaces the Legiones Astartes as the primary front-line ground forces of the Imperium, with the Adeptus Astartes reserved for more specialist roles such as planetstrikes and special operations. 
* Second Founding (021.M31) - Roboute Guilliman summons his brother Primarchs to Terra. There he presents his Codex Astartes, and counsels that the Legions must be broken down into Chapters. Dorn, Vulkan and Leman Russ vehemently oppose this motion, while Corax and the Khan side with Guilliman. With tensions rising, it appears as though the Imperium has survived one civil war only to be plunged into another, However, at the eleventh hour Rogal Dorn relents, recognising that his actions are motivated by pride and anger instead of reason. With disaster averted, the Second Founding takes place, and dozens of new Space Marine Chapters are born. 
* The Ravens' Fate (ca. M32) - A sudden degeneration afflicts the gene-seed of the Raven Guard, causing organs to fail and implants to be rejected. From this time onward, the Raven Guard are forced to rely on gene-seed stocks from Terra, a factor that slows the Chapter’s recruitment rates significantly but does not curtail their willingness for battle. 
* The Beast Arises (544.M32) - The greatest Ork invasion the Imperium has ever known to this time threatens to bring Humanity to its knees. It is the combined forces of the Adeptus Astartes who stem the green tide, at great cost. 
* Reunited (646.M32) - A one-hundred-standard-year period of anarchy is ended by the intervention of the Space Marines. Agnathio, Chapter Master of the Ultramarines, unites over fifty Chapters of Space Marines and arrives upon Terra. Agnathio holds a locked council with the squabbling noble "rulers" of Terra. What is said has never come to light, but when the Space Marine fleets return to their homeworlds, there once again sit twelve High Lords of Terra, and unity is restored to the Imperium. 
* The Apocrypha of Davio (ca. M33) - A great and holy document attempts to list all of the Chapters of the Second Founding. It is a worthy work, but remains incomplete. 
* The Howling (401.M34) - The Black Templars Chapter end the Catelexis Heresy by executing the Cacodominus, an alien cyborg whose formidable psychic presence allowed it to control the populance of thirteen hundred planetary systems. Alas, the Cacodominus' death scream echoes and amplifies through the Warp, burning out the minds of a billion Astropaths and distorting the signal of the Astronomican. Millions upon millions of Imperial voidships are lost in the resulting upheaval and entire sub-sectors slide into barbarism without the dictats of the Adeptus Terra to guide them. 
* The Moirae Schism (ca. M35) - The Adeptus Mechanicus is torn apart by conflict and internal division during the time of internal religious strife known as the Moirae Schism. The Adeptus Astartes are not immune to such conflicts; the Iron Hands, due to their close connection to the Mechanicus, are most severely affected. The result of the religious discord is the unexpected birth of the Sons of Medusa Chapter. 
* The Cursed Founding (991.M35) -  In an attempt to "improve" the creation of Space Marines the Adeptus Mechanicus tinkers with the genetic structure of the gene-seed used in the Cursed 21st Founding. The resulting Chapters of the Adeptus Astartes suffer myriad anomalies and many become corrupted by Chaos or suffer from rampant mutation and other disorders. 
* Armoured Assault (282.M36) - The massed armoured spearheads of the Aurora Chapter break the Ork invasion of the world of Grylos. 
* The Abyssal Crusade (321.M37) - Saint Basillius the Elder finds thirty Space Marine Chapters wanting in faith. The guilty must choose either death or to embark upon a redemptive Crusade into the Eye of Terror. All of the Chapters choose the latter mission, known as the Abyssal Crusade, and enter the Eye as an armada with their livery obscured and honour in doubt. Few return, only to discover that Basillius was actually a pawn of Chaos seeking to weaken the defences of the Imperium. 
* Fateweaver Denied (798.M37) - The White Consuls prevail against the daemonic legions of Kairos Fateweaver. 
* The Heavenfall Massacres (956.M37) 
* Firestorm (ca. M38) - A Daemonic incursion overruns Innocence III. Dropping from orbit, the Salamanders' 6th Company endure terrible casualties in order to defend the planet's three remaining shrine cities and their civilian populace. With the cities safe, the vengeful Salamanders purge the Daemons from Innocence III with fire and blade. 
* The Judgement of Basillius (112.M38) - The Vorpal Swords return from the Eye of Terror, leading the survivors of the Abyssal Crusade, to cast down the Chaos-tainted Saint Basillius. 
* The Siege of Haddrake Tor (ca. M40) - The Imperial Fists besiege a Chaos stronghold on Haddrake Tor. After 1st Company Captain Kleitus is killed in a teleportation mishap, Sergeant Darnath Lysander takes up the fallen hero’s weapon, the Fist of Dorn, and swears vengeance. He smashes down the gates to the heretic fortress and leads his beleaguered brothers to victory against the odds, and is named 1st Company Captain just days later. 
* Battle for Columnus (ca. M40) - The forge world of Columnus is set upon by a vast Ork WAAAGH!. Aiding the Technomagi in its defence are elements of the Iron Hands and Raven Guard. The battle for Columnus is horrifically costly, largely thanks to the callous defensive strategies of the Iron Hands. Though victory is secured, rumours persist about the fate of the Raven Guard, supposedly wiped out while serving as unwitting bait in an Iron Hands trap. 
* The Gothic War Begins (139.M41) - The 12th Black Crusade of Abaddon the Despoiler, also known as the Gothic War, begins in the Segmentum Obscurus' Gothic Sector. Before it is ended, it will draw in many Chapters of the Adeptus Astartes. 
* The Jorun Retaliation (143.M41) - The Dark Eldar Kabal of the Crimson Libation incite the wrath of the Ultramarines, Howling Griffons and Sons of Orar. The Dark Eldar are defeated, but not before the Howling Griffons' Chaplain, Armand Titus, succumbs to xenos poison and is interred within a Dreadnought. 
* The Macharian Crusade (392-399.M41) - The Macharian Crusade was a monumental, seven-year-long Imperial Crusade fought between 392.M41 and 399.M41, led by Lord Commander Solar Macharius, the Imperium's greatest Astra Militarum commander of all time and a recognised tactical and strategic genius on a par with the Primarchs themselves. This Crusade took place on the far western edge of the galaxy within the Segmentum Pacificus, reaching as far as the border of the galaxy with intergalactic space and even reaching into the unknown regions of the Halo Zone. The furthest extent of this Crusade reached just beyond the edge of the Segmentum Pacificus, where not even the blessed light of the Astronomican could penetrate the dark void. Most Imperial savants agree that Macharius was the most successful and brilliant Imperial Warmaster since the Arch-Traitor Horus. Nearly a thousand worlds were brought back into the Imperial fold in only seven standard years of fighting. 
* The Macharian Heresy (399-469.M41) - After Lord Solar Macharius' death, the territories that he conquered fall to war and strife. Seventy standard years of turmoil ensues and is ended only through the combined efforts of a hundred Space Marine Chapters, working across many far-flung sectors to restore order to the region in what is known as the Macharian Heresy. 
* The Gaudinian Snare (460.M41) - On Gaudinia Prime, a Slaaneshi daemonic entity, known as the Sapphire King, and his minions attempt to turn the Iron Hands to Chaos by unleashing a mutagenic spell into the Space Marine ranks. Fuelled by the Iron Hands' own repressed rage, the spell wreaks absolute havoc, escalating quickly towards disaster. It is only stopped when Kardan Stronos orders his brothers to disengage inhibitor protocols and free their anger upon the foe. Rallying, the surviving Iron Hands purge their enemies with uncharacteristic zeal. 
* The Corinthian Crusade (698.M41) - Marneus Calgar leads the Ultramarines, Angels of Absolution, Lamenters, Silver Skulls, Scythes of the Emperor, Marines Errant and fifty Imperial Guard regiments against WAAAGH! Skargor in the Corinthian Crusade. The Orks are crushed, and their threat diminished for over thirty standard years. 
* The Damocles Gulf Crusade (742.M41) - In an Imperial Crusade to drive Tau invaders from Imperial worlds in the Damocles Gulf region of the Segmentum Ultima, the Novamarines are noted for their relentless persecution of all xenos life forms. Only their recall to serve in the First Tyrannic War prevents them from being present at the Imperial assault on the Tau Sept world of Dal'yth. This campaign is known as the Damocles Gulf Crusade. 
* A Wedge Between Allies (744.M41) - After joining forces to defeat the Alpha Legion responsible for the Redemption Rebellion, the Knights of the Raven and the Aurora Chapter swear a bitter feud against each other, each blaming the other for their grievous losses. 
* The First Tyrannic War (745.M41) - The Ultramarines and forces of the Imperial Navy successfully end the First Tyrannic War against Hive Fleet Behemoth at the Battle of Macragge, though the effort costs the lives of the entire Ultramarines 1st Company. 
* The Blood Star Campaign (748.M41) - A massive daemonic incursion into the Scarus Sector is heralded by the star Ares turning an ominous blood red. The Relictors, Rainbow Warriors and Fire Lords eventually halt the invasion but take grievous casualties, including the loss of all three Chapter Masters. The Imperium grieves for three of its mightiest heroes. 
* The Siege of Vraks (813.M41) - The Red Scorpions and Red Hunters fight to retake the Armoury World of Vraks Prime during the terrible campaign of attrition known as the Siege of Vraks. The seventeen-year-long conflict is deemed a success as the daemons and Chaos Space Marines are repulsed. However, Vraks is reduced to the state of a Dead World as the entire civilian population is wiped out in the fighting. 
* The Lithon Purge (833.M41) - Over a hundred billion Imperial citizens are slain or captured by Dark Eldar in the Lithon System. The Revilers spend many solar months purging the xenos from the system and swear vengeance on those that escape into the Webway. 
* The Doom of Idharae (852.M41) - The Invaders Chapter launch a direct assault on the Eldar Craftworld Idharae. Though the Space Marines suffer horrific casualties, they leave the Craftworld a ruined and desolate hulk, devoid of all life. 
* The Lazar Blockade (857.M41) - The Silver Skulls' fleet blockades the Lazar System. Offering no explanation for their presence, they prosecute a secret mission to purge Necrons from the system. They obliterate the main Necron Tomb World, but secondary bases throughout the system suddenly come to life. The Silver Skulls suffer greatly, and their forces scatter into disarray. They are eventually forced to withdraw from Lazar, but to this day no outsider has ever learned the truth of what happened there. 
* The Hellabore Assault (867.M41) - Captain Alessio Cortez and the Crimson Fists 4th Company battle the Eldar of Craftworld Iyanden on the world of Hellabore. Despite suffering grievous wounds, including a stab wound to one of his hearts, Cortez leads the final assault that routs the Eldar from Hellabore. 
* The Badab War Begins (901.M41) - Lugft Huron, Chapter Master of the Astral Claws, refuses to hand over his gene-seed tithe to the Administratum and instead announces his secession from the Imperium, declaring himself the ruling "Tyrant of Badab" in the Badab Sector of the Maelstrom Zone. Over a standard decade of bitter inter-system war follows, embroiling more than a dozen Space Marine Chapters before Badab falls and the Astral Claws escape to the Warp rift known as the Maelstrom at the conclusion of the internecine conflict named the Badab War. 
* The World Engine (925.M41) - The Necron World Engine is revealed as the architect of the destruction seen in the Vidar Sector at this time. It is destroyed on the edge of the Doranno System, thanks chiefly to the noble and complete sacrifice of the Astral Knights Chapter. 
* The Toran VI Massacres(934.M41) - The Crimson Fists defeat the Chaos Space Marine warband of the Chaos Lord Sathash the Golden. 
* The Revenge of the Eldar (936.M41) - Craftworld Alaitoc launches a devastating attack on the Invaders' Chapter Planet. Only three companies escape the disaster and their fortress-monastery is lost. The Invaders are thereafter a fleet-based Chapter. 
* Battle of the Black Star (939.M41) - In the sable light of the star Antilles, the Dark Hunters strike at the Renegade Punishers' stronghold, claiming over half the Traitor Marines' lives. 
* The Timeaon Deliverance (940.M41) - The Iron Snakes are ambushed during the Timeaon Planetstrike by Tau Battlesuits and saved from certain death only when the Legion of the Damned appear and launch a devastating assault on the aliens' flanks. 
* The Defence of Orask (940-997.M41) - The Red Talons successfully hold the Fortress World of Orask at the edge of the Ghoul Stars from invasion by a splinter of Hive Fleet Pythos. In recognition of their hardfought victory, the Senatorium Ultima of Ultramar honour the Chapter with the gift of the famed relic known as the Bloody Crown of Hycani. 
* The Second War for Armageddon Begins (941.M41) - When the Ork Warlord Ghazghkull Thraka unleashes a massive Ork WAAAGH! on the strategic Hive World of Armageddon in the Segmentum Solar, many Space Marine Chapters participate in its defence during what becomes known as the Second War for Armageddon. 
* The Folly of Heroes (955.M41) - Despite direct orders to the contrary, the Brazen Claws launch a counterstrike into the Eye of Terror itself. Their last transmissions indicate the Chapter engaging a fleet of Iron Warriors vessels, but no other trace is heard of them. 
* The Soulmaw (956.M41) - With most of their Chapter lured away by a distress call, the Silver Skulls barely manage to resist an attack on their homeworld of Varsavia by the daemonic warband known as "the Soulmaw." 
* The Bellicas Disaster (970.M41) - The Emperor's Swords Chapter is wiped out when a Necron Tomb stirs to life in the caverns of their Chapter Planet, Bellicas. 
* The Rynn's World Disaster (989.M41) - WAAAGH! Snagrod rampages across the Loki Sector, culminating with a devastating assault on Rynn's World. The Crimson Fists Chapter is left depleted and bloodied after an Imperial expedition, including many Space Marine Chapters, retakes the planet from the Orks, but they are determined to rebuild all that was lost. 
* Flaming Vengeance (990.M41) - The Fire Lords Chapter descends on Bellicas, exterminating the Necron menace and setting the planet aflame to avenge the destruction of the Emperor's Swords. 
* The Second Tyrannic War (992-993.M41) - The Lamenters and Scythes of the Emperor Chapters are virtually destroyed fighting against the menace of Hive Fleet Kraken. 
* Broken But Unbowed (994.M41) - Once thought destroyed in the Eye of Terror, the Brazen Claws resurface near Cadia, battered, but still fighting their long war against the Forces of Chaos. 
* The Hive Mind Hungers (995.M41) - The tendrils of the Tyranid Hive Fleet Jormungandr begin to brush against the northeastern boundaries of the Imperium. The Death Spectres and Honoured Sons lead the counterattack. 
* The Leviathan Blunted (509.997.M41) - Elements of the Ultramarines and Mortifactors Chapters stand victoriously against a spur of Hive Fleet Leviathan on Tarsis Ultra during the Third Tyrannic War. 
* The Lament of Angels (997.M41) - The Angels Revenant Chapter is destroyed while defending its fortress-monastery on the world of Liberthra against the onslaught of the Necron Maynarkh Dynasty. The Bells of Lamentation sound throughout Segmentum Tempestus at their passing. 
* WAAAGH! Irontoof (550.998.M41) - The Genesis Chapter, alongside its Primogenitors the Ultramarines, combat and defeat the growing might of the Ork WAAAGH! Irontoof. 
* The Third War for Armageddon (757.998.M41) - The Ork Warlord Ghazghkull Thraka returns to Armageddon at the head of a new, even greater, WAAAGH! More than twenty Space Marine Chapters, including the White Scars, Salamanders, Doom Eagles, Storm Lords and Exorcists, commit forces to the beleaguered war zone. The Ork WAAAGH! is eventually broken on Armageddon during the terrible campaign remembered as the Third War for Armageddon and Ghazghkull flees into the void, pursued by the Black Templars and Commissar Yarrick who have sworn to end the wily Ork Warlord's threat to the Imperium once and for all. 
* War in the Gildar Rift (998.M41) - The Silver Skulls destroy a Red Corsair strike force. The surviving Renegades make planetfall on several worlds in the Gildar System, but the Silver Skulls will not be thwarted and the taint of the Renegades is cleansed in a matter of weeks. 
* The Black Sun (672.999.M41) - The Exorcists Chapter rushes to confront the daemonic incursions around the sun Sirie. 
* Rebirth (970.999.M41) - The Scythes of the Emperor finally emerge from the dark shadow of Hive Fleet Kraken and announce that their Chapter will be born anew. 
* The Maelstrom Threat (980.999.M41) - A vast Chaos Space Marine fleet under the command of Huron Blackheart emerges from the Maelstrom and besieges the Chogoris, Kaelas and Sessec Systems. Rumours report Huron's force is as large as the Space Marine Legions of old, and several Chapters are tasked with its destruction. 
* The 13th Black Crusade (995.999.M41) - Many Space Marine Chapters converge on the sectors surrounding the Eye of Terror in a desperate attempt to counter the influx of vile forces led by Abaddon the Despoiler in the course of his 13th Black Crusade, the largest and most potent Chaos incursion into Imperial space since the Horus Heresy. Some say it is truly the Time of Ending, yet the Adeptus Astartes stand strong in the face of their greatest enemy. The Chaos forces are successfully contained on the surface of the Fortress World of Cadia and prove unable to break out of the Cadian Gate, though their forces remain in realspace for the first time in 10,000 standard years.
== Founding of a Space Marine Chapter ==
New Space Marine Chapters are not created piecemeal as required by the Imperium's strategic needs, but rather in deliberate groupings called "Foundings." The process by which a new Founding's creation is approved by the Imperial government is mysterious and arcane, subject to decades or even centuries of planning before it is announced. It is only by an edict of the High Lords of Terra that such an undertaking as the creation of new Chapters can be instigated, for it requires the cooperation and mobilisation of countless divisions within the Imperium's monolithic and vast governmental organisations. Establishing new Astartes Chapters on an individual basis is nigh impossible--the mobilisation of such vast resources is beyond the ability of any single segment of the Imperium. 
The Adeptus Mechanicus plays an essential role in the process of a Founding, for its highest echelons are tasked with creating, testing and developing the gene-seed samples that will provide the genetic foundation of the new Chapters. Entire Forge Worlds may be turned over to the manufacture of the mighty arsenal of weaponry, ammunition, Power Armour, vehicles and starships that any such force will require. There are a myriad of other concerns as well. A suitable homeworld inhabited by humans must be identified for the new Chapter, which will likely provide not only a secure and defensible base of operations, but also a source of new recruits as well. Such worlds might have been reported by itinerant Rogue Traders and earmarked centuries before by Adeptus Mechanicus Explorators as potential Astartes homeworlds. A degree of environmental terraforming might be required and the natives of the world (if they are to become the source of the new Chapter's Aspirants) must be studied and tested by the Mechanicus' Magos Biologis and Genetors for many generations to ensure they are genetically pure and free of any strain of mutation that might later affect the Chapter itself. The construction of a Chapter's fortress-monastery may be one of the greatest undertakings of all, drawing on the genius of the Imperium's most accomplished military architects and engineers. If the Chapter is to be fleet-based, then even more work must be put into the construction of a massive Chapter Barque or an unusually large Battle Barge to serve as the Chapter's mobile fortress-monastery and all of the related capital warships and Escorts such a highly-mobile Chapter will require. 
The already extant Space Marine Chapters may also have a role in this process, though to what degree can vary greatly from Founding to Founding. Many of the First Founding Chapters maintain close links with Chapters created using their own gene-seed stocks, and the Chapter Masters might have a hand in planning future Foundings using that genetic material. It is said that the Disciples of Caliban, a Dark Angels Successor Chapter, was created following the direct appeal of the Supreme Grand Master of the Dark Angels, an extremely rare request. 
In the more than 10,000 standard years that have passed since the First Founding of the 20 original Space Marine Legions by the Emperor, there have been 25 subsequent Foundings of new Chapters of the Adeptus Astartes; with the most recent, the 26th Founding, occurring in the year 738.M41, approximately 250 standard years ago. Even before a new Founding is announced, entire generations of Imperial servants may have toiled in preparation. Even once the process has been declared and is underway, it is likely to be at least a standard century before the new Chapters are ready to begin combat operations. In times of dire need for the Imperium, faster development has been attempted, but this has often resulted in disaster. Gene-seed cultured in haste is likely to degrade or to mutate, and a great many other factors can lead the entire process astray. And there is no foe more dangerous to the Imperium of Man that a Space Marine who has been corrupted by Chaos or gone Renegade for another reason. 
== Space Marine Recruitment ==
Each Chapter of Space Marines has its own methods of recruiting young warriors to fill its ranks. Many are based on a single homeworld and recruit solely from that populace, setting trials and tests for prospective candidates to weed out all but the strongest and the most faithful. These worlds are often technologically backward with strong militaristic societies, where male children who show potential are pushed harder and harder, that they may one day have a chance to join the ranks of the Space Marines, who are often known to such peoples as "star warriors," "sky knights," or similar names. Because Feral Worlds are rough, primitive, and untamed, their inhabitants invariably provide excellent recruits. For true aggression and nigh-psychotic killer-instinct, however, few recruits can best the murderous city-scum that roam the darkest pits of the Imperium's many Hive Worlds. Driven to extremes of violence by the pressures of Hive World living, these merciless killers are usually ignored by the authorities. They make ideal Space Marine recruits, and whole gangs of city-scum are sometimes hunted down and made to undergo the Trials. Some recruits are drawn from the more Civilised Worlds of the Imperium, but not very many. 
Those planets used by the Space Marines as recruiting worlds are observed closely by the Chapter’s Apothecaries and Chaplains. The population’s genetic purity must be maintained, in order to conserve those qualities that serve the Space Marines’ purposes best. Their spiritual health is also maintained, to ensure that no trace of the influence of the Ruinous Powers becomes manifest. Such observations are in general carried out from a distance, and it is rare for the society to have any direct contact with, or knowledge of, the Space Marines, or in many cases even of the Imperium. The Chapter’s officers might visit the culture once a generation and will be the subject of myth and legend. These mighty warriors from beyond the stars are figures of awe, and their word is law. The nature of the trials set by the outsiders vary enormously, but all are so arduous that only a handful pass them. Those who fail may be lucky to even survive, for many trials take the form of ritual combat, the hunting of a great beast, or the performance of incredibly dangerous feats of strength and bravery. At the conclusion of the trials, those few Aspirants that have been deemed worthy are taken away, invariably never to see their people again. 
It is always a great honour for a family to have a son chosen by the Space Marines, even for societies with little conception of the greater galaxy beyond their world. The Space Wolves are an example of this. The Wolf Priests of the Space Wolves scour the warring tribes of their homeworld Fenris for their strongest and bravest youths, while the Ultramarines traditionally draw their candidates from the elite training barracks of a whole group of planetary systems known collectively as Ultramar, the realm of the Ultramarines. Other Chapters have no single homeworld and travel the galaxy in gigantic fleets of battleships, recruiting either from a regular series of worlds or from the war zones to which they are assigned. The Black Templars are one such example of a fleet-based Chapter, as are the Dark Angels. Once accepted, the young Aspirants become Neophytes and begin their regimen of training and biological enhancement. Each Chapter has its own traditions regarding the initiation of the recruit into its legends and secrets. This process often runs parallel to the bio-genetic treatments the Neophyte must undergo. As the physical transformation proceeds, spiritual change also occurs. Both are tempered by ongoing experience on the field of battle and the rituals in which the Neophyte must participate. The nature of such rites varies enormously from one Chapter to the next. 
Some are solemn affairs recalling the sacrifice the Emperor made for humanity. Others are raucous celebrations drawing on the culture and nature of the Chapter’s home world. Still more are bloody and barbaric involving ritual bloodletting, scarification, or amputation. All are vital to the arcane workings of the Chapter, and his participation is a prerequisite of the Neophyte’s acceptance by his would-be brothers-in-arms. Such are the rigours of the training that many do not survive. Whether he is crippled upon the battlefield, or found spiritually wanting during a particularly exacting ritual, a Neophyte may find himself cast out, his future with the Chapter curtailed. In some instances, the Neophyte may transgress one of the many articles of Chapter law, and injury at war may prove preferable to the punishment. Many possible fates await those who fall by the wayside in this manner. Most are mind-scrubbed and become Chapter Serfs—manservants and menials. The less fortunate are transformed into living, cybernetic Servitors—mindless biomechanical automatons who exist only to assist the Chapter’s Techmarines in the operation of heavy and frequently dangerous machinery. A very rare few may yet rise to positions of relative power within the Chapter’s feudal household, yet even the highest-ranked factotum is but a lowly, nameless servant in the eyes of the full Battle-Brothers. 
The worlds that the Space Marines recruit from often have a wide range of legends regarding the Adeptus Astartes. As many of the communities in question are primitive or barbaric, the people regard the Space Marines as otherworldy figures, "angels of death" who arrive once in a generation to test them and carry away their strongest sons. On more advanced worlds, the people will have more of an understanding of who and what the Adeptus Astartes are regard the success of an Aspirant as an honour to the entire community. On some worlds, the knowledge that a distant ancestor was recruited into the Astartes is as good as a patent of nobility and portraits of the legendary hero adorn the walls and prayers are said to him as if he were a saint of the Imperial Cult in times of need. 
=== Aspirant Trials ===
Aspirants to become Space Marines are expected to overcome many and varied trials before being accepted into the ranks of a Chapter's Neophytes. Though he will undergo continuous testing throughout his time as a Neophyte, and often well beyond after he becomes an Initiate or Scout Marine, the first trial the Aspirant must pass to be accepted as a potential Astartes is by far the most significant of his young life. The events he experiences during that trial will live on in his mind and heart for the rest of his potentially long, long life. Every Chapter of the Adeptus Astartes uses some form of Trial to ascertain whether Aspirants are worthy of beginning the often-fatal process of becoming fully-fledged Battle-Brothers. The nature of this Trial varies greatly from Chapter to Chapter and world to world. In some cases, a culture's traditional festivals and rites of passage are in fact well-disguised Trials, established generations before and watched over in secret by Chaplains or senior Chapter Serfs. In such cases, the Aspirants believe they are participating in tribal rituals and coming-of-age challenges, and are entirely unaware that the most promising of their number will be selected to become Space Marines (if they even know what Space Marines are!). In other cultures, the Aspirants fight for the honour to be judged worthy, knowing that a great reward awaits the victors. 
Again, they may not know the exact nature of that reward, but to be chosen is the greatest of honours a young man can aspire to. Some Trials are watched over closely by the servants of the Chapter, who judge the Aspirant every step of the way. Others have no interest in the actual process, only the outcome. Some Trials are so arduous that the simple fact of an Aspirant's surviving it is sufficient to pronounce his victory. In other cases, the manner in which the Aspirant approaches the challenge is judged of more importance than whether or not he completes it--in some cases, the Trial is deliberately impossible to complete, and the Aspirant's willingness to undertake it regardless is all that matters. The vast majority of Aspirants fail their Trials and many of these die in the process--though a failed Aspirant who lives through the Trial often garners much honour within his culture, his mere survival rendering him a hero and a potential future leader of his people. At the Trial's completion, a successful Aspirant will be taken away to join the Chapter as a Neophyte. Sometimes he will find a Space Marine waiting for him at the conclusion of his challenge and be led into a waiting transport to leave his former life forever. Sometimes he will be afforded the adulation of his people before leaving, enjoying one last night with kith and kin. Many simply awaken in an induction-cell, with no knowledge of how they got there or what awaits them. In any case, the successful completion of their Trials allows an Aspirant to become a Neophyte of the Chapter, though now he must pass a battery of tests to determine if he is worthy of being implanted with the sacred and life-altering gene-seed organs of the Astartes
=== Blood Duel Trial ===
One of the most common Aspirant Trials takes the form of a duel between Aspirants, often to the death. The type of duel varies enormously and every culture from which the Astartes recruit has its own well-established practices. On different worlds, different weapons will be used, or sometimes none at all as the combatants are expected to pummel, gouge and throttle one another bloody. Feral world tribes might use flint-tipped spears or the shapened, serrated fangs of wild beasts. Feudal worlds with a medieval level of technology might use highly-ritualised forms of swordplay, while the most advanced Imperial worlds would have access to the full gamut of lethal weaponry. Commonly, a Blood Duel is fought in rounds, with Aspirants facing foe after foe until only a small number remain. If the Chapter conducting the Trial has need of a large number of recruits, the Trial may be ended when a set number of Aspirants are left. When the Chapter has less need of new Neophytes, the Trials may continue until only a single battered and bloody challenger remains, the corpses of his enemies carpeting the ground before him. Not all Blood Duels are to the death and some have highly ritualistic and specific victory conditions. Sometimes the duel is fought to first blood, other times to the very point of death. The Space Marine Apothecaries are capable of rebuilding a crippled body should the Aspirant be deemed worthy of acceptance, so most Blood Duels are brutal, no-holds-barred affairs. The Blood Angels Chapter is known to make extensive use of the Blood Duel Trial, but plenty of other Chapters make use of similar methods of choosing their recruits, including the Dark Angels, Imperial Fists, Storm Wardens and Space Wolves.
=== Hunting the Hunter Trial ===
Many of the cultures from which the Astartes recruits exist in hellishly dangerous environments populated by all manner of predatory beings. In most cases, the predators in question are autochthonic beasts native to the world, but sometimes they have been deliberately introduced in order to retard the culture's development, ensuring that their every moment is a fight for survival and cultivating the most promising recruits possible. In many cases the predators are human, such as the gelt-scalpers that prey on the outcasts of hive societies, culling the unwanted for monetary reward. Frontier worlds are often plagued by alien raiders, ranging from the dreaded and lethal Dark Eldar to the barbarous greenskinned Orks. This Trial requires the Aspirant to track down and slay, or sometimes capture, such a predator, turning the tables on those who prey upon his people and proving his worthiness to become an Astartes Neophyte. The hunt is a test of cunning and determination as much as raw martial prowess, often requiring the Aspirant to track his prey in its own territory. The hunt may last days, weeks or even longer according to the conditions of the Trial and the weapons the Aspirant can either find or fashion for himself. Taking the target alive is perhaps the hardest of Trials, for the Aspirant must keep the foe restrained on a return journey that might prove every bit as arduous as the hunt itself. 
A variation of the hunt requires a number of Aspirants to hunt a single target, though only one may claim victory. Some of these Aspirants strike out on their own, even turning on their fellows when the opportunity arises. Others set aside their rivalry and work together until the end. Those Aspirants who survive must eventually fight one another for the honour of claiming victory. Whatever path the Aspirants take, the Chapter learns much about their potential recruits. At the conclusion of a Trial in which a prisoner is taken, it is common for the Aspirant to be required to slay his captive, often before his people in a highly ritualised deed akin to a ceremonial sacrifice. Thus, the blood offering is made and the victor led away to join the ranks of the sky warriors. The Space Wolves are known to use the Hunting the Hunter Trial, requiring the Aspirant to track and face a fearsome Fenrisian Wolf or a Snow Troll. The Dark Angels have a similar tradition drawn from the knightly orders of their lost homeworld of Caliban and often require Aspirants to track and kill fearsome beasts mutated by the powers of Chaos.
=== Survival of the Fittest Trial ===
It is often said that in the dark future of the 41st Millennium there is only war. No world is untouched by bloodshed and death and for many human societies war is a permanent state of existence. Many of the worlds from which Space Marine Chapters recruit are not home to a single, unified society, but rather a host of small tribes constantly at war with one another. In such societies, Trials are all but unnecessary and instead of staging formal tests and challenges the Space marines simply watch these wars from afar, witness the deeds of the greatest heroes and select the victors as Aspirants. Hive worlds often fall into this category, especially the lawless underhives and the polluted ash wastes between the hive cities. Gangs of savage psychopaths battle one another ceaselessly for power and influence and the greatest of these gang leaders sometimes attract the attentions of the servants of the Chapter. In most cases, the Space Marines need to do little more than watch the wars, but in some instances they actively take a hand in fomenting conflict and strife. By limiting the technology levels of a society, curtailing its access to natural resources, infiltrating it with Chapter serfs who spread hate, lies and paranoia, and occasionally even introducing psychosis-inducing substances into the food chain, the Astartes can ensure there is no break in the constant state of warfare that produces the Chapter's next heroes. The Chapters best known for practicing this type of Trial are the Space Wolves, who watch from afar as entire tribes on their frigid homeworld of Fenris wipe one another out in bloody internecine wars. Many other Chapters use similar methods as well, including the Dark Angels and their Unforgiven Successor Chapters.
=== Exposure Trial ===
Few worlds of the Imperium of Man are free from adversity and these rare exceptions are either the holdings of wealthy mercantile combines or pleasure retreats for retired, high-level Imperial servants or the local sector nobility, entirely inaccessible to the vast bulk of Mankind. Most of the Emperor's subjects live on worlds that are dangerous in some manner. Long-settled planets are riven by pollution, the toxic waste of thousands of years of industry seeping into the very bedrock and raining from the skies in a constant downpour. Other worlds are heavily irradiated, by the processes of industry or by the effects of local celestial phenomena. Younger worlds where Mankind's dominion is not yet fully established, are often host to all manner of hostile lifeforms, including predatory beasts, carnivorous plants and virulent microbes. Plenty of worlds feature environments that are inimical to life, yet due to some natural resource or the world's strategic value, humans eke out an existence there nonetheless. Such environments range from sub-zero ice wastes, impenetrable swamps and arid deserts to exotic death world jungles, methane sumps and hydrocarbon oceans. In an Exposure Trial, the Aspirant must go out into such an environment and simply survive for a set period of time. If he is a native of such a hellish place, the Aspirant will have some knowledge of how to survive, yet is shorn of all aid and divested of all but the most basic of survival equipment. Communities living in the midst of a death world jungle, for example, rely on total and constant cooperation just to go on exisitng another day and none are ever out of the sight of another. An Exposure Trial in such a place would force the Aspirant to go out into the jungle alone and face the terrors of the wild with only himself to rely upon for the first time in his life. 
Some Exposure Trials test the Aspirant's fortitude in a specific environment. Such Trials carried out in an icy waste could involve the Aspirant travelling from one point to another, with countless hundreds of kilometres of trackless snow-blasted plains separating the two. Other Aspirants might have to cross an entire continent of irradiated ash dunes, traverse an impassable mountain range, swim a predator-infested ocean or a hundred other such challenges. One particularly inventive variation of the Exposure Trial is one in which the Aspirant is taken from his own environment and transplanted into an entirely unfamiliar one. A Feral World savage might be deposited in a hive city, for example, or a Hive Worlder in a predator-infested Death World jungle. Many Exposure Trials are impossible to complete, entailing the Aspirant simply staying alive as long as possible. Those who face the impossible without faltering and who survive long past the point they should have perished are recovered by the Chapter's Apothecaries, often having succumbed but not yet died, and revived, having been judged worthy of becoming an Astartes Neophyte. Amongst other types of Trial, the Ultramarines make extensive use of the Exposure Trial. In fact, some of the warrior elite of the Realm of Ultramar are known to cast newborn infants into the wilderness in order to test their resilience. The Space Wolves use similar methods, as do many other Chapters.
=== Knowledge of Self Trial ===
The horrors that a Space Marine will witness during his service to the Emperor are sufficient to destroy a normal man's sanity and those witnessed by the Battle-Brothers who serve in the special Astartes units like the Grey Knights and the Deathwatch are more horrifying still. Many Chapters consider the Aspirant's spiritual and mental capabilities every bit as important as his physical characteristics and impose Trials not of the body, but of the mind. There are hundreds--if not thousands--of ways in which a Chapter can test an Aspirant's inner strength. One method is a vision, imposed by way of psychic intrusion by one of the Chapter's Librarians. The Aspirant may be plunged into a trance-like state during which he is subjected to all manner of horrific visions or irresistible temptations. He faces creatures dredged up from his own nightmares and phantoms seeded in his mind by the Librarian, who presides over the Trial and judges the Aspirant's very soul. Some Trials are far cruder; the Aspirant is simply administered some powerful psychoactive concoction, often distilled from the venom of local predators or the sap of rare plants. Under the influence of such drugs, the Aspirant must face the very worst his own psyche can produce, terrors often far worse than a Librarian could implant. Many die under the sheer stress and trauma placed on their hearts during the process and those that survive will be utterly changed--physically as well as mentally. Another common variation of this Trial is exposure to pain. There are myriad different ways in which pain can be applied, some primitive, others fiendishly inventive. Some torments leave the Aspirant scarred for life, though the scars are proudly borne as evidence of his mental strength. Others, such as the infamous Pain-Glove used by the Imperial Fists Chapter, leave no marks, interfacing directly with the Aspirant's nervous system and keeping his conscious long past the point he would otherwise have passed out. Though the Imperial Fists are the best known practitioners of this type of Trial, many other Chapters use it too, especially those that recruit from feral societies with strong shamanic tendencies. The Black Templars use similar methods but eschew the use of drugs or technology, instead requiring an Aspirant to fast or pray for days on end until a similar effect is achieved.
=== Challenger Trial ===
A Trial used by a smaller number of Chapters, the Challenge requires the Aspirant to fight a duel or compete in some other manner against a full Astartes. In truth, none expect the Aspirant to better a full Battle-Brother and his success is more often measured in the degree of his failure. Very occassionally, an Aspirant does manage to beat an Astartes and when this happens it is not uncommon for the individual to go on to become a legendary hero of the Chapter. Many Challenge Trials involve a test of martial skill, with the Aspirant fighting an armed duel against a Battle-Brother. It is usual for the Aspirant to be armed and the Astartes to fight with his bare hands and probably without his Power Armour, yet still the Aspirant has virtually no hope of victory. Most Challenge Duels end in the death of the Aspirant, for even an unarmed, unarmoured Astartes is a giant compared to the young, adolescent challenger and well able to slay him with a single blow, intentionally or not. Other Challenge Trials involve contests of strength, stamina, speed, skill or mental strength. The Trial might range from the lifting of impossibly heavy loads to the imbibing of toxic substances. As with a duel, this type of Challenge Trial can often prove deadly. In both cases, however, an Aspirant that has failed the Trial -- yet performed to the Chapter's satisfaction -- is rescued from the jaws of death by the Chapter's Apothecaries and judged worthy of progressing to the rank of Neophyte. Several Chapters are known to make use of the Challenge Trial, including the Ultramarines, Imperial Fists, Storm Wardens and Iron Snakes.
=== Gene-Seed ===
The gene-seed of an Astartes is the foreign genetic material originally engineered using one of the Primarchs' genomes as a foundation. The gene-seed develops into the special organs that are then implanted into a potential Space Marine's body. These gene-seed organs are responsible for most of a Space Marine's physical enhancements over baseline human capability. All Space Marine gene-seed was originally cultivated by the Emperor himself from the DNA of the Emperor's 20 genetically-engineered sons (each son being the Primarch of one of the 20 Space Marine Legions of the First Founding), and is a rare and precious resource for the Space Marines of the Imperium, even in death. The biotechnology necessary to create new gene-seed has long been forgotten or lost to humanity; therefore, it must be cultivated from dead/dying Astartes warriors and returned to the Chapter's Apothecaries, who will oversee the creation of new Astartes from the Chapter's raw recruits. The gene-seed is the very essence of a Space Marine Chapter and it carries each of the characteristics that are particularly unique to a given Chapter, be they mental, physical, spiritual, or martial.
Unfortunately, Space Marine gene-seed is vulnerable to mutations over time, which can phenotypically manifest in various ways. In addition, there are various genetic flaws that have developed in the gene-seed, the majority of which derive from the particularities of each Primarch's genetic code. It is these mutations that led to the emergence of the Flaws in the Blood Angels' gene-seed (specifically their susceptibility to the conditions known as the Black Rage and the Red Thirst), the "Mark of the Wulfen" for the Space Wolves or the rapidly increasing rate of mutation that afflicts the Renegade Soul Drinkers Chapter. 
It must also be noted that the presently existing Space Marine Chapters are more numerous than the original 20 Space Marine Legions, excluding those two Legions that were removed from Imperial records. Only the original 9 Legions that remained loyal to the Emperor during the Horus Heresy produced the numerous Space Marine Chapters of the Second Founding who share traits with their founder Chapter, which is itself the remnant of one of the Loyalist Legions. 
During the recruitment and enhancement process, some Aspirants may not survive the rigours of training and the later medical treatments one must undergo to become a full-fledged Battle-Brother of the Chapter. First and foremost, a potential Space Marine recruit must be male, as the gene-seed and the developing Space Marine organs are compatible only with male hormones and genetics. Trying to implant a woman with Space Marine gene-seed would result only in a painful, agonising death. The three following requirements also apply: 
* Space Marine Aspirants must be adolescents or very young adults, as the implants must be able to coordinate with a human male's natural growth hormones during adolescence to stimulate the growth and development of the various unique physiological features of a Space Marine. In specific terms, the recruit must be about 10-16 Terran standard years of age, although the process has been documented to still work in recruits as old as 20 as long as they have not yet reached their full adult growth. 
* Much like a blood transfusion or organ transplant, there must be immunogenetic compatibility between the recruit and the implants; otherwise organ failure may result, causing the recruit to die or simply degenerate into a state of madness as their own tissues come under autoimmune attack. 
* The mental state of a potential Space Marine must also be susceptible to the various training and psycho-conditioning regimes of the Chapter and cannot already be tainted by the Ruinous Powers of Chaos. 
These three main criteria bar all except a minuscule percentage of human males within the Imperium of Man from becoming Space Marines. If all the tests prove successful, the Space Marine recruit transforms from a Neophyte into a Scout Marine or even a full Initiate depending on the Chapter's individual organisation. The recruit is then taken to live at the Chapter's fortress-monastery where he is instructed in the ways of battle and taught the values and history of the Chapter. At this stage, organ implantation, psycho-conditioning, and physical training begin. Each step in this stage has its own dangers, ensuring that only the truly worthy initiates become Space Marines. After several years of training, conditioning, and implantation surgeries the Initiate becomes a true Astartes, undergoes his Rites of Fire in his first combat action, and becomes a true Battle-Brother of his Chapter.
=== Implantation of Astartes Organs ===
Nineteen genetically-engineered organs grown from the Chapter's gene-seed are implanted in a Neophyte's body to further bolster his combat and survival ability should he live to become a full Battle-Brother and Initiate of the Chapter. Many of these organs are cultured in vitro from the gene-seed, whilst others require that the gene-seed be injected into the Aspirant's body and then grow into a new organ using the implantee's own physiological processes. All Space Marine Chapters use the gene-seed organs to unleash and control the metabolic processes that transform an ordinary mortal into a Space Marine. The gene-seed itself is encoded with all the genetic information needed to reshape ordinary human cell clusters into the special organs Space Marines possess in those instances where they are not directly implanted after being cultured outside the body. The gene-seed contains genetically-engineered viral machines which rebuild the male human body according to the biological template contained within it and created by the Emperor. However, even from the beginning of the Astartes' existence, there was never a set way to activate these transformative functions of the gene-seed. 
During the First Founding of the 30th Millennium when the Space Marine Legions were first created, the process was still highly experimental and many different ways of controlling and managing the transformation from mortal into Astartes were tried. This led to the Space Wolves using the ritual known as Blooding, the Imperial Fists using the process known as the Hand of Faith, the White Scars conducting the Rites of the Risen Moon and the Blood Angels using the ritual of Insanguination. 
Each implant has a high margin of catastrophic metabolic failure and physiological rejection and so only a small number of Neophytes live to become Initiates of the Chapter and enter the 10th Company as Scout Marines. Many Chapters have lost the knowledge needed to culture new versions of some of these implants, and therefore, must ensure this gene-seed is recovered from dead Battle-Brothers. Amongst the crucial implants are the Interface, better known as the Black Carapace, and the Progenoid Glands, without which a Chapter would die out fairly quickly. The gene-seed organs must be implanted into an adolescent human male for the process to have the greatest chance of success no later than his 16th year, though it is medically possible to begin the process as late as 18 years of age before full growth has been reached in the early 20's. However, a gene-seed organ implantation procedure done at this late stage in the boy's growth will as likely kill him as not. In general, most Space Marine Chapters prefer to begin the process sometime between the ages of 10 and 14 years. The full list of 19 gene-seed organs, presented in the order in which they must be implanted within a Space Marine Neophyte, is as follows:
# Secondary Heart (The Maintainer) - This is the first and least difficult implant to install. The Secondary Heart increases blood supply and pumping capacity and is capable of taking over entirely should the primary heart fail. It may also pump steroids and adrenaline into the first, primary heart to give the Astartes an extra "rush" of energy on the battlefield.
# Ossmodula (The Ironheart) - This implant strengthens and greatly accelerates the growth of the skeleton of a Space Marine by inducing his bones to absorb a ceramic-based mineral administered in every Astartes Neophyte's diet. Within two years after the surgery, the Space Marine's skeleton will be larger and exponentially stronger than a normal man's with growth having topped out at around 7-7.5 feet in height with an equivalent amount of skeleto-muscular mass. An Astartes' rib cage will also be fused into a solid bone plate to provide greater protection from injury for the internal organs. 
# Biscopea (The Forge of Strength) - Implanted into the chest cavity, this implant massively bolsters skeletomuscular development and muscle fiber density throughout the Astartes' body by unleashing a wave of human growth hormones. This gene-seed organ is commonly implanted at the same time as the Ossmodula since it is necessary to successfully regulate the Ossmodula's hormonal secretions and it will also regulate the hormonal changes caused to the new Astartes' body by many of the other gene-seed implants. 
# Haemastamen (The Blood Maker) - Implanted into a main blood vessel like the aorta, femoral artery or the vena cava, the Haemastamen alters an Astartes' blood's biochemical composition to carry oxygen and nutrients more efficiently. The actions of the Haemastamen turn a Space Marine's blood a brighter shade of red than that of normal humans because of its greatly increased oxygen-carrying capacity. It also acts to biochemically regulate the actions of the 2nd and 3rd gene-seed implants, the and . 
# Larraman's Organ (The Healer) - Shaped like the human liver but only the size of a golf ball, this gene-seed organ is placed within the chest cavity and manufactures the synthetic biological cells known as Larraman Cells.These biosynthetic cells serve the same physiological purpose for an Astartes as the normal human body's platelets, serving to clot the blood lost from wounds, but they act faster, more efficiently and more effectively. When a Space Marine is wounded and incurs blood loss, Larraman Cells are released by his circulatory system, attached to the body's normal leukocytes (white blood cells). At the site of the injury, they form scar tissue in a matter of seconds, effectively preventing massive blood loss and infection of the wound. The action of this organ is one of the reasons that the Space Marines are seen as nearly invincible and so difficult to kill despite the terrible wounds they sometimes endure. 
# Catalepsean Node (The Unsleeping) - Implanted into the back of the cerebrum, this implant allows a Space Marine to avoid sleep, instead entering an almost comatose trance where their minds "recharge". It also allows one half of the brain to rest while the other hemisphere remains alert, thus removing the need for the unconsciousness required by normal sleep. The longest any Space Marine has ever been on active combat duty without rest is 328 hours, achieved by a squad of the Crimson Fists during the battle against the for . 
# Preomnor (The Neutraliser) - The Preomnor is essentially an organic decontamination chamber that is implanted inside the chest cavity and connected to the digestive system, above the original stomach so that no actual digestion occurrs in the Preomnor. It is capable of biochemically analyzing ingested materials and neutralizing most known biochemical and inorganic toxins. The Preomnor enables the Astartes to eat normally inedible substances and resist any poisons he may ingest. 
# Omophagea (The Remembrancer) - Implanted into the upper spinal cord so that it becomes a component of the central nervous system, this organ is designed to absorb information and any DNA, RNA or protein sequences related to experience or memory. This enables the Space Marine to gain information, in a survival or tactical sense, simply by eating an animal indigenous to an alien world and then experiencing some of what that creature did before its death. Over time, mutations in this implant's gene-seed have given some Chapters an unnatural craving for blood or flesh. 
# Multi-lung (The Imbiber) - The Multi-lung is a third lung implanted into an Astartes' pulmonary and circulatory systems in the chest cavity that is able to absorb oxygen from environments usually too poor in oxygen to allow normal human respiratory functioning. Breathing is accomplished through a sphincter implanted into the trachea, allowing all three lungs to be used at full capacity. In toxic environments, a similar muscle closes off the normal lungs, thus oxygen is absorbed exclusively by the Multi-lung, which then filters out the poisonous or toxic elements. 
# Occulobe (The Eye of Vengeance) - Essentially, the Occulobe is a gene-seed organ that enhances an Astartes' eyesight after being implanted along the optic nerve and connected to the retina, granting him exceptional vision and the ability to see normally in a low-light environment. 
# Lyman's Ear (The Sentinel) - This gene-seed organ implant renders a Space Marine immune to dizziness and motion-induced nausea, and enables an Astartes to consciously filter out "white noise" or resist other sonic attacks. 
# Sus-an Membrane (The Hibernator) - This implant allows a Space Marine to enter a catatonic or "suspended animation" state and is implanted within the brain near the pituitary gland as a part of the body's endocrine system. It can allow a mortally wounded Astartes to survive his injuries, and bring the metabolism to a standstill until he can receive full medical care. Only the appropriate chemical therapy or hypnotic auto-suggestion can revive a from this state. The longest recorded period for this form of hibernation was endured by Battle-Brother Silas Err of the Chapter, who was in Sus-an hibernation for 567 standard years. 
# Melanochrome - Linked into the endocrine system via the lymphatic system, this gene-seed organ alters the pigment cells in the skin, which allows the Astartes' skin to shield him from otherwise dangerous levels of radiation and heat. Different levels of radiation cause variations of skin color in different Chapters due to mutations in the Melanochrome organ's gene-seed. This can be related to the unusually pale skin of the and their Successor Chapters and the dark black skin and red eyes of the . 
# Oolitic Kidney(The Purifier) - This gene-seed organ works in conjunction with the Preomnor, filtering the blood to remove toxins that have been ingested or breathed into the body. However, this detoxification process renders the Astartes unconscious once it begins, so it can be very dangerous if required during combat. Under normal circumstances, the Oolitic Kidney also acts as a regulatory organ for the Astartes physiology, maintaining the efficient action of the Space Marine's advanced circulatory system and the proper functioning of his other organs, implanted or otherwise. 
# Neuroglottis (The Devourer) - This gene-seed organ implanted in the mouth allows an Astartes to biochemically assess a wide variety of things simply by taste or smell, biochemically testing various objects for toxicity and nutritional content, essentially determining if the substance is edible or poisonous. From poisons to chemicals to animals, a Space Marine can even track his quarry by taste or smell alone, much like the average canine bred for tracking. 
# Mucranoid (The Weaver) - This gene-seed organ is implanted within the central nervous system and responds to specific chemical stimuli in the environment, causing the Space Marine to secrete a waxy protein substance similar to mucus through his pores that seals his skin. The gland's operations must first be activated by an external chemical treatment, usually self-administered, before it will activate. Space Marines are cocooned in this way before they enter suspended animation, and the process can even protect them from the harshness of the vacuum and other extremes of temperature, particularly deeply frigid environments. 
# Betcher's Gland (The Poison Bite) - Actually consisting of 2 separate glands implanted into multiple locations inside an Astartes' mouth, including the inside of the lower lip, in the salivary glands or in the hard palette, these two glands work in tandem to transform a Space Marine's saliva into a corrosive, blinding acid when consciously triggered. An Astartes trapped behind iron bars, for example, would be able to chew his way out given a few hours. These implants' more common use is to aid in the digestion of unusually difficult or impossible things to digest, such as cellulose. In the gene-seed of several , like that of , this organ has atrophied and is no longer as effective or has simply ceased to function entirely in the Astartes of the Chapters that use those Primarchs' gene-seed. 
# Progenoid Glands (The Gene-seeds) - Implanted into both the neck and the chest cavity, these reproductive glands serve to collect, gestate and maintain the gene-seed from a Space Marine's body, and to safeguard it for the continuity of a Chapter. These organs hormonally respond to the presence of the other Astartes gene-seed implants in the body by creating germ cells with DNA identical to that of those implants through a process very similar to cellular mitosis. These germ cells grow and are stored in the Progenoid organs, much like sperm cells or egg cells are stored in the testes and ovaries of normal men and women. When properly cultured by the of a Space Marine Chapter, these germ cells can be gestated into each of the 19 gene-seed organs needed to create a new Space Marine. Thus, for most Astartes, their Progenoid Glands represent the only form of reproduction they will ever know, though the DNA passed on will be that of their , not their own. The neck gland can be removed after 5 years, and the chest gland after 10 years; both are then used to create new gene-seed organs for the development of the next generation of Space Marines. 
# The Black Carapace (Interface) - The last and possibly most important of all gene-seed implants, this neuroreactive, fibrous organic material is implanted directly under the skin in the chest area of the hardened and shell-like ribcage of the Astartes Neophyte. Invasive fibre bundles that serve as neuron connectors then grow inward from the implant and interlink with the Space Marine's central nervous system. Points pre-cut into the Carapace before its implantation by the are effectively neural connection points, allowing an Astartes to directly interface his central nervous system with his suit of 's so that the suit can provide enhanced protection and combat maneuverability unavailable to an unaltered human wearing the same armour. 
Throughout the implantation process, a Space Marine Neophyte must undergo multiple regimens of chemical and hyno-theraphy treatments in order for the implanted organs to develop normally and function properly so that they integrate without mishap into the new Astartes' physiology. Too many Neophytes have been lost during the implantation process as their bodies proved critically unable to meet the new biochemical and hormonal stress being placed upon them. For these unlucky indviduals, the only recourse is usually euthanasia or being reduced to a mindless cybernetic Servitor who can still prove to be of at least marginal use to the Chapter. The full course of implantation surgeries begins under ideal conditions between the ages of 10-14 years as outlined below: 
* Age 10-14: The Secondary Heart, Ossmodula and Biscopea are implanted, with the Ossmodula and the Biscopea usually being implanted during the same surgical procedure. 
* Age 12-14: The Haemastamen and the Larraman's Organ are implanted. This surgery can be difficult for Neophytes at the older end of this age range, who have less time to recover from the previous surgeries and the effects of the implants upon their rapidly growing adolescent bodies. 
* Age 14-17: Once the Catalepsean Node is implanted at the sixth stage of the process, the Neophyte begins his hypno-therapy conditioning in the device known as a Hypnomat. 
* Age 14-16: The Preomnor, Omophagea, and Multi-lung are all implanted within the Neophyte simultaneously in the same surgical procedure, some time during this age range but after the Catalepsean Node has been implanted and hypno-therapy has already begun. The Occulobe, Lyman's Ear, and the Sus-an Membrane can also be implanted at any time during this age range, also usually during the same surgical procedure. 
* Age 15-16: The Melanochrome, Oolitic Kidney, and Neuroglottis are ideally implanted during this age range, all during the same surgical procedure. 
* Age 16-18: The remaining gene-seed implants, the Mucranoid, Betcher's Gland, Progenoid Glands and the Black Carapace, are implanted in that order at any time between the ages of 16 to 18 standard years. The idea is to be able to introduce a Neophyte into a Chapter's company of Scout Marines by the time his adult growth has been reached, usually around 18 years of age, though some Neophytes have become Scouts as early as the age of 16 if their implantation process began at the young end of the age ranges given here. 
=== Conditioning ===
In addition to the extensive implantation process for the gene-seed organs, the Astartes Neophyte undergoes chemical treatment, psychological conditioning, and subconscious hypnotherapy, all the while spending every waking hour honing his combat skills with ceaseless battle training. Until his acceptance as a full Initiate and Battle-Brother of his Chapter, a Neophyte must submit to constant tests and examinations by the Chapter Apothecaries. The newly implanted organs must be monitored very carefully, imbalances corrected, and any sign of corrupt or deviant development treated. This chemical treatment is reduced after completion of the initiation process, but it never ends. Space Marines undergo periodic drug treatment for the rest of their lives in order to maintain a stable metabolism. To this end, Space Marine Power Armour contains extensive physiological monitoring and drug dispensation equipment. As the super-enhanced body grows, the recipient of the gene-seed organs must learn how to use his new skills. Some of the implants, specifically the Catalespean Node and Occulobe, can only function once correct hypnotherapy has been administered. Hypnotherapy is not always as effective as chemical treatment, but it can have substantial results. If a Space Marine can be taught how to control his own metabolism, his dependence on drugs is lessened. The process is undertaken in a machine called a Hypnomat. Space Marines are placed in a state of hypnosis and subjected to visual and aural images in order to awaken their minds to their unconscious metabolic processes. 
A Space Marine is more than just a human being with extraordinary powers. Just as their bodies receive 19 separate gene-seed implants, so their minds are altered to release the latent powers that lie within all human minds, and these are not the psychic powers of the Warp but the intrinsic . These mental powers are, if anything, more extraordinary than even the physical powers endowed by the gene-seed implants. For example, a Space Marine can control his senses and nervous system to a remarkable degree, and can consequently endure pain that would kill a normal man. A Space Marine can also think and react at lightning speeds. Memory training is an important part of the Astartes' psycho-indoctrination as well and some Space Marines develop photographic memories in the course of their psychoconditioning and hypnotherapy. Space Marines, of course, vary in intelligence as do other men, and their individual mental abilities vary to some degree, as their implants do not reshape their core neural architecture, though the hypnotherapy does act to "smooth out" many personality quirks. This indoctrination also includes psychological conditioning which is intended to reinforce a Space Marine's respect for authority and his willingness to follow orders regardless of his own desires, as well as to harden his mind to the corruptive temptations offered by Chaos. It is no exaggeration to say that many Astartes truly no longer know fear. At the end of this process, if all goes well, an adolescent human male will have been transformed into a superhuman Astartes. Yet, in many ways he will no longer truly be human, having sacrificed his own humanity so that he might protect that of others.
== Space Marine Combat Doctrine ==
The Space Marines of the Adeptus Astartes are the greatest fighting force of the Imperium of Man. Genetically-enhanced to serve Mankind as humanity's ultimate warriors, they are far stronger and more resilient than even the most exceptional unenhanced human beings. The majority of the Space Marine Chapters operating within Imperial space are comprised of 1,000 Astartes organised into 10 companies of 100 warriors each. Every Chapter is fiercely proud of its history and achievements and each is marked out by its own distinctive colours and Chapter heraldry. These colours and iconography were established at the time of each Chapter's Founding and are displayed with unadulterated pride upon all armour and vehicles owned by the Chapter. The wargear of the Chapter is maintained with painstaking precision and many items have been covered over the millennia in fine lines of intricate devotional script in High Gothic, with each line detailing a battle honour of the Chapter won by a previous user of the weapon. Each Chapter is commanded by an officer usually known as a Chapter Master, who holds a rank equivalent within the Imperial hierarchy to that of a Planetary Governor. Each Chapter is a small, mobile army and although each contains only 1,000 Battle-Brothers, a Chapter's actual combat potential is equivalent to at least ten times that number of normal troops drawn from the Astra Militarum (Imperial Guard). Each Chapter has its own transports, support staff, armourers and Chapter fleets of warships and are intended to respond to any type of threat that can emerge anywhere in the galaxy. Because they are so mobile compared to other Imperial military units, the Space Marines are often the first servants of the Emperor to arrive at a scene of conflict and they are used to mount deep strikes, raids and devastating surprise attacks. 
The archetypal mission for which the Space Marines were created over 10,000 Terran years ago is the planetstrike, or planetary assault. Such an offensive begins with the Astartes' Chapter fleet engaging with and clearing away any defending starships and neutralising the target world's orbital defences, ground-based laser batteries and missile silos. Enemy ground defences are sabotaged by the Chapter's Scout Marine forces or captured by full Astartes from its Battle Companies. Often the bulk of a Space Marine force deployed to a planetary assault will deploy directly into battle, forcing a decisive engagement to take advantage of the considerable shock of their appearance upon the field. When the Space Marines arrive in this manner they must deploy as rapidly as possible to maintain the element of surprise that plays such a crucial role for them in achieving battlefield success. To this end, Space Marine warships are equipped with hundreds of Drop Pods and large hangar bays filled with deadly Thunderhawk gunships. The contrails of these craft high in a world's atmosphere are often the only harbinger of a Space Marine assault. As the Chapter's Drop Pods and Thunderhawks streak through the embattled sky towards their rendezvous with blood and fire, the enemies of the Emperor come to realise that their doom is at hand. The Space Marines always prefer to deploy right into the heart of the enemy's force and proceed to unleash a devastating barrage of Bolter fire. The initial shock of this assault can often break an enemy force before a campaign has barely begun, ending a rebellion or forcing an alien invader off-world in one fell stroke. These shock assaults are usually spearheaded by squads of Terminators drawn from a Chapter's Veteran 1st Company who teleport directly into the heart of the foes' lines and are supported by heavier units like armoured vehicles that have been delivered to the world's surface by Thunderhawk Transporters. 
Each company of a Chapter is able to field a mix of Tactical, Assault and Devastator Squads depending on its type. An entire company of Astartes is rarely fielded as a tactical force. Instead, each Space Marine force is exactly tailored to the tactical requirements of the combat mission at hand, usually with elements drawn from the versatile Battle Companies. Such a force might consist of only 3 or 4 squads supported by individual squads drawn from other companies, as well as a complement of armoured vehicles and Dreadnoughts. This force will be led into combat by a Captain, a senior Veteran Sergeant, a Chaplain or a Librarian who serves as the Force Commander. 
On very rare occasions, a Space Marine Chapter will be called upon to carry out a mission or face an enemy of such size and power that it must deploy a large portion of its total strength. In these instances, forces consisting of 200 or even 300 Astartes and their supporting vehicles are not uncommon. Such a force is deployed only to those locations where the enemy's advance must be stopped at all costs. For instance, during the Second and Third Wars for Armageddon it was determined by the High Lords of Terra that the Ork Warlord Ghazghkull Thraka had to be prevented from extending his WAAAGH! beyond that strategically located Hive World lest his Greenskin hordes gain footholds on more populous worlds in the Segmentum Solar and wreak absolute havok on the Imperium's heart. As such, several legendary Astartes Chapters like the Blood Angels, Salamanders and Black Templars deployed several full Battle Companies in their supreme effort to halt the advance of the Orks. Such was their skill that Armageddon became a new word for total war in the Ork "kultur." 
The nature of the Adeptus Astartes' missions means that a Chapter's various components may be spread across the galaxy at any one time, with individual detachments involved in separate conflicts thousands of light years apart. It is very unusual for all 10 companies of a Chapter to be gathered in the same place at the same time and centuries can pass between gatherings of an entire Chapter for a single mission. As a result, the deployment of an entire Space Marine Chapter indicates the need to combat a threat that may rend the very fabric of the Imperium itself if left undefeated. The deployment of such a force can only be requested by the High Lords of Terra and is led by the Chapter Master in person. Such a gathering of martial power can bring a Fortress World to its knees, halt an alien invasion or even hurl back a Black Crusade. Legendary, existential threats to the Emperor's realm such as the Helican Schism, the Macharian Heresies and the Tyrannic Wars have seen the need to call up entire Chapters. Whole worlds have become shrines to remember the fallen of these conflicts. Each of these campaigns engulfed large regions of Imperial space and involved countless millions of troops, yet were ultimately decided only by the unmatched heroism of a relatively small number of the Emperor's Angels of Death, the Space Marines.
== Path of a Space Marine ==
According to the Codex Astartes, Space Marines are organised into three main types of squad: Tactical, Assault, and Devastator. Each of these squads has a unique battlefield role and is designed to operate together to provide mutual support and maximum flexibility. In addition to these three squad types, the 1st (Veteran) Company can be formed into Terminator or Veteran squads, while the Scouts of the 10th Company are always fielded as Scout Squads. All Space Marine squad types, with the exception of the Scouts, normally consist of 10 Astartes, but they can be divided into two separate combat squads in battle. This gives each unit a further degree of flexibility in action. An Aspirant who becomes a Neophyte and is accepted into the Chapter’s ranks will serve in many roles, starting out as a young Scout Marine in the 10th Company and, if fate favours him, progressing through the ranks as an Initiate and full Battle-Brother of the Chapter, serving as Devastator Marine, Assault Marine, Tactical Marine and, if he is exceptionally bold, eventually earning the honour of serving as a Veteran in the elite 1st Company. A favoured few excel even past this great honour and join the ranks of the Chapter’s officers, leading their fellows into the blood and fury of battle. 
The first step along the path to becoming a mighty hero of the Chapter is service in one of the Scout Squads of the 10th Company. Scout Squads consist of a Veteran Space Marine Sergeant and four to nine Scout Marines. The role of the Sergeant is to train the Scouts and lead them in battle. Only Sergeants of considerable experience and status are designated for this role. Scouts attend to every word their Sergeant utters, for it is said that he has forgotten more of war than many more senior officers will ever learn. Whilst serving as a Scout, a Neophyte learns the most subtle arts of war. In a range of infiltration and reconnaissance missions, he learns how to approach and observe the enemy. Information gathered in such missions is passed back to the main battle force. The Scouts get their first taste of combat by way of carefully placed ambushes, the Scout Sergeant drawing on centuries of experience to deploy his charges in such a manner as to teach them as valuable a lesson as the enemy. Unlike that enemy, the Scouts learn valuable skills in such combats—the enemy earns nothing more than a quick death, for even a Neophyte Space Marine is a potent warrior compared to a mortal man. 
A Space Marine serving in a Devastator Squad may only recently have completed his service in the 10th Company and been accepted as a full Initiate and Battle-Brother of the Chapter. It will be his first experience of fighting in Power Armour. When first assigned to such a squad, the Space Marine will bear a Bolter and grenades and fulfill a support role within the squad, providing close support to those Battle-Brothers armed with heavy weapons, identifying targets and being close at hand to proffer ammunition and to take up the weapons of any who should fall. Only when he has proven himself steady and reliable in battle will the Space Marine be entrusted with one of the Chapter’s mighty heavy weapons, which he will come to master over the course of several hundred battles. Devastator Squads consist of a Sergeant and nine Space Marines. Up to four Space Marines may be armed with heavy weapons, whilst the remainder will carry Bolters. This is the most heavily armed type of Space Marine squad, and they are deployed wherever overwhelming firepower is needed, especially when the Chapter faces enemy armour or fortified positions. 
Having proved himself steadfast and disciplined in the Devastator Squads, a Space Marine will in time earn himself a place in his company's Assault Squads. Here the Space Marine comes to master the application of overwhelming force, taking the fight directly to the enemy’s strong points. He embraces the controlled savagery of close combat and looks his enemy in the eye as he deals him death. Assault Squads are specialists at fighting in hand-to-hand combat. Each squad consists of a Sergeant and nine Space Marines all equipped with Jump Packs and armed with a close combat weapon in each hand. Common armament consists of a Bolt Pistol and a Chainsword. Optionally, two of the Space Marines may carry Plasma Pistols. This combination is ideal for fast-attacking, close-quarter fighting assault troops. 
Even though Tactical Squads are the most common type of squad in any Chapter, to earn a place in one a Space Marine must have proven himself both courageous and wise in battle. Throughout his service in the Devastator and Assault Squads, he will be proven adaptable in his approach to the arts of war and will have mastered a range of tactics and weaponry. Tactical Squads are the most commonly fielded squad types in a Chapter. A Tactical squad is led by a Sergeant and includes nine other Space Marines. Of these, seven Battle-Brothers are armed with Bolters, whilst the remaining two can be armed with Bolters or, alternatively, one may carry a heavy weapon such as a missile launcher or a Heavy Bolter, and the other may carry a special weapon such as a Flamer or Meltagun. This combination is the most tactically flexible and offers a good mixture of capabilities within the squad. 
After serving in hundreds of campaigns and thousands of battles, and having conquered the very worst the galaxy has to throw at him, a Space Marine is likely to be considered a Veteran. In most Chapters, such an honour is not measured by length of service, but in blood spilled, horrors overcome, and mighty deeds done. As a prelude to service in the elite 1st Company, many Space Marine Veterans fulfill the role of Sergeant, leading squads of all types in any of the other companies. Thus, many of the Space Marines of the Veteran company will be battle-proven leaders as well as highly experienced warriors. The warriors of the Veteran company are fielded in one of three squad types: Terminator Squads wear the uniquely powerful Terminator Armour, sometimes called Tactical Dreadnought Armour. This armoured suit is massive in construction, virtually turning a Space Marine into a one-man tank. Every Chapter has a limited number of Terminator Armour suits, and each is an ancient artefact crafted many thousands of years ago. Terminators are less mobile than other Space Marines and are primarily used in starship boarding actions or in extreme close quarters when heavy fire support cannot be easily brought to bear. So resilient is the armour that it is reputedly able to operate inside plasma reactors, within volcanoes, and inside highly irradiated areas of deep space. Legend has it that the armour can even survive the tread of a Titan. To wear an ancient suit of Terminator Armour is one of the greatest honours to which a Space Marine can aspire. Each suit bears on its left shoulder the Crux Terminatus, the unique honour badge of the Terminator. Each Crux is said to contain at its core a tiny fragment of the armour worn by the Emperor himself when he fought his final battle against the traitor Warmaster Horus, providing a direct link between the Space Marine and the Father of Mankind. 
Despite its obvious benefits, Terminator Armour is not suitable for all missions. Most of the time, Veterans take to the field wearing ordinary Power Armour, albeit a suit inscribed with many hundreds of battle honours as well as the Crux Terminatus. When wearing Power Armour, Veterans are formed into Vanguard Veteran Squads or Sternguard Veteran Squads. By dint of their rank, Veterans have access to the most fearsome weaponry in the Chapter’s Armoury, including sacred blades and Artificer-crafted combi-weapons of uniquely masterful craftsmanship. Vanguard Veteran Squads go to battle equipped with the most lethal of close combat weapons, and often wear Jump Packs to bring them to bear before the enemy can even react. Sternguard Veteran squads carry a wide array of ranged weaponry and specialised ammunition, and are masters in its overwhelming application. Veteran squads are rarely deployed en masse, but are instead used to bolster the line, provide an unstoppable speartip or to act as a highly flexible and mobile reserve. 
Each of the Chapter’s ten companies is led by a Captain. These leaders are second in experience only to the Chapter Master himself, and each is a warrior so deadly that he will rarely meet his match. Each Captain is an inspirational and determined leader, able to coordinate the Space Marines under his command whatever the opposition. In addition to leading Space Marines in battle, each Captain holds titles dependent on his other responsibilities with regard to the workings of the Chapter or its home world, such as Master of the Fleet or Master of the Marches. 
Of the thousand awesome and terrifying warriors that comprise a Space Marine Chapter, there is but one Chapter Master, a leader with centuries of experience in the very crucible of battle. His own fighting skills will be unsurpassed, whether in the use of gun, blade, or bare hands. His very rank speaks of a past littered with the bodies of bloodied, beaten foes of the most terrifying and inhuman sort. It is not enough, however, for the Chapter Master to be its foremost warrior. He must also be a superb tactician, grounded in the teachings of the Codex Astartes and honed through countless decisions made in the maelstrom of close action. His warriors are also his brothers, and he knows that they will give their lives at his command. He must preserve these magnificent troops, but must also accomplish his mission and uphold the honour of his Chapter. He will be steeped in the lore of his Chapter and be sworn to keep its secrets and must conduct his diplomacy accordingly, for Space Marines maintain a web of time-proven oaths and honour debts and do not simply heed the commands of Imperial functionaries, no matter how impressive their title. Those who wish a Chapter Master to send his warriors into battle must give him good reason to do so. In addition to this, a Chapter Master will often be the ruler of his Chapter homeworld, a resource that is too valuable for him to ignore. Amongst the greatest risks facing a Chapter Master is the very power he wields, for a Chapter of Space Marines is a force capable of devastating entire worlds at his order. It is an Astartes' very power that can lead to hubris. And it is hubris that can so easily condemn even a Space Marine's soul to damnation as those dedicated to the protection of Mankind may come to believe they should rule it instead.
== Bonds of Brotherhood ==
A Space Marine has three levels of interaction that shapes who he is: the overall Chapter views and beliefs, the battle doctrine and mind-set of his Battle Company, and the individual bonds he forges with his squad-mates with whom he fights side-by-side. 
* The Chapter - The first bond that all Space Marines share is the bond that makes them part of their Chapter. This is coded into their flesh through the gene-seed they all share, dating back to their Primarch. Even Chapters of the subsequent Foundings share this trait, no matter how far they are removed from the lineage of their progenitor. The beliefs and combat doctrine of the Chapter for most is rooted in the Codex Astartes, the tome of tactics and strategy created by Roboute Guilliman after the Horus Heresy. It is at the Chapter level that the command structure, battle doctrine, and many inherent beliefs are created for the Space Marine. A member of the Space Wolves knows that it is his duty to take the battle to the foes of the Emperor directly, bringing death with sword and Bolter in close quarters. The same cannot be said of an Iron Hand, who favours dealing death from afar with master-crafted weaponry and war machines. The belief structure created by the Chapter becomes everything to the Battle-Brother. Many Initiates come from Feudal or Feral Worlds, who know nothing of the Imperium and the greater universe, so it is through their indoctrination into the Chapter that everything they know of the galaxy is taught. If the Librarians and Chaplains of the Chapter teach these young men that they must entreat the Machine Spirits to make their Bolters fire and their starships traverse the void of space, many do not think any differently and this will become simple fact to the Aspirant. Another Chapter will teach its brethren the intricate ways of maintaining their weaponry and how the Imperium actually works and functions. These wildly disparate views on the basic structures of the universe around them can lead to interesting interactions when Astartes of different Chapters must work together. 
* The Company - Once an Aspirant has become a Space Marine, he is placed into a company. At the company level, a Space Marine learns the deeper structure of how he will fight the enemies of Mankind. The Codex Astartes outlines the progression of each Battle-Brother through the companies of their Chapter and what skills he shall gain during his tenure in each. According to the Codex Astartes, a Battle-Brother progresses from a Scout Marine of the 10th Company, to a Devastator of the 9th Company, then on to an Assault Marine of the 8th Company. Once a Space Marine has mastered the many ways in which he is capable of making war, only then is he ready to enter the Tactical Squads of his Chapter's Battle and Reserve Companies. Space Marine companies often have many ancient traditions and rites based on their past battles and achievements. These become very important to the Battle-Brother and will greatly influence him. For example, a member of the Blood Ravens' 5th Company, who lost many of his brothers in a prolonged campaign against the Eldar, may observe an annual rite commemorating the sacrifices made to bring about victory. Missing this observance -- if not in an active battle situation -- could bring about a sense of melancholy and shame to the Battle-Brother, who feels he is not properly honouring his fallen comrades. 
* The Squad - The most intimate bonds are amongst the Battle-Brothers of the Space Marine's squad. Day in and day out, these hardened warriors fight alongside each other for the glory of the Emperor and the Imperium. With each battle, the members of the squad become more ingrained in the ways of battle and how to rely on each other in any circumstance. It is within a squad -- and that can be Tactical, Assault, Devastator, or Scout Squad -- that the Astartes has spent the most time. If he leaves his squad for another, to begin his tenure with the Deathwatch, or for some other reason, he must leave a part of himself behind, and learn how to function on a whole new level as part of a new team.
== Relations with the Astra Militarism ==
The Astra Militarum, known coloquially as the Imperial Guard, is composed of men and women possessed of unquenchable faith in the God-Emperor of Mankind, but they are still ultimately mortals of flesh and blood. To the common troopers, the superhuman Space Marines of the Adeptus Astartes are as gods walking amongst men and for most of the common people of the Imperium, including the troops of the Imperial Guard, they are a rare sight indeed. Most Astra Militarum troopers will never see a Space Marine, let alone fight alongside one, and as such they are the subjects of all manner of legends, myths, and superstitions. Different Imperial cultures, and the Imperial Guard regiments drawn from them, have their own beliefs about Space Marines. Some hold them in awe as the literal sons of the Emperor, whilst others fear them as the deliverers of the Emperor’s divine judgement. While it is true that a Space Marine can spit acid, in their ignorance many claim they can also kill with a glance or rout an army with a single word. Tales abound of small groups of Space Marines conquering entire planets or holding off wave after wave of slavering xenos fiends. Some Chapters, in particular the Ultramarines, are lionised across the Imperium. Others, such as the Blood Drinkers, inspire dread. 
Any Imperial Guard trooper (or any other mortal for that matter) finding himself in the presence of a Space Marine is likely to drop to his knees in abject supplication, so potent is the martial bearing of a Battle-Brother of the Adeptus Astartes. Even senior Imperial Guard officers might find themselves stammering like newly commissioned subalterns when conversing with a Space Marine. In the main, most Space Marines barely notice mere mortals and it takes a great and rare man indeed to earn their respect. Rumours of their presence in a war zone can often generate great excitement amongst Imperial Guardsmen, but such rumours often prove to be false. An encounter with a single squad of Space Marines is a legendary encounter for the mortals of the present-day Imperium, even those mortals who are themselves pledged to the Emperor's service, and will result in hushed tales of awe told around the tables of the officers’ mess for many years to come.
== Space Marine Armour ==
=== Scout Armour ===
Scout Armour is a lighter, less-encumbering version of standard Imperial Carapace Armour often used by elite Imperial Guard troops like Storm Troopers or Kasrkin that offers excellent protection while at the same time being extremely well-suited for stealth and skirmishing missions. In most Codex Astartes-compliant Chapters, Neophyte Space Marines (Scout Marines) serve in the 10th Company as Scouts for their first assignment. Scouts are placed under the instruction of an experienced Scout Sergeant, who both takes command of the squad and teaches the Scouts what it means to be a Space Marine. This type of armour is usually only worn by Scout Marines. Since their Black Carapace has yet to mature, they are still unable to interface with standard Space Marine Power Armour, so are instead allowed to wear a suit consisting of carbon-titanium composite plates. Scout Armour is still capable of stopping the majority of small-arms fire. In times of relative peace, full Battle-Brothers of certain Chapters may take to wearing Scout Armour during periods outside of battle.
=== Power Armour ===
Possibly the most prominent feature of the Space Marines is their Power Armour, which is a synthesis of many technologies that pre-date even the Age of Strife, stretching back into the Dark Age of Technology. The suit is comprised of multiple custom-crafted Ceramite plates with armoured fiber bundles and servos that replicate the wearer's movements and enhances a Space Marine's already superhuman strength, as well as allowing them to easily withstand brutal attacks that would rip a normal human apart. The armour itself can also act as a self-containing environment for the suit's owner, protecting the Space Marine from mulitple hostile surroundings, including the dark vacuum of deep space and the most toxic planetary environments that the universe can provide. The armour interacts with the Space Marine's nervous system through the Black Carapace, a subcutaneous membrane grown beneath the skin following gene-seed implantation that allows the Astartes' internal organs and nervous system to interface directly with the suit of Power Armour, so that the armour in essence becomes literally an extension of the wearer's body. The most current Space Marine Power Armour model is the Mark VII or Aquila Pattern. The Mark VII remains the most common suit of Power Armour in use by the Space Marine Chapters in the late 41st Millennium. However, it is not uncommon for parts of older Power Armour patterns to be used to replace damaged areas of a Mark VII suit as this saves precious resources. An example of this type of retrofitting is that some Astartes are known to have rivets on certain parts of their Power Armour. These pieces are actually derived from the ancient Mark II Crusade Pattern armour that dates back to the time of the Great Crusade over ten standard millenia ago. These patched suits of Power Armour protect their wearers just as well as their updated counterparts since the only real change in Power Armour patterns over the last 10,000 terran years have been to the armour's myriad auxiliary systems. What few know is that each Space Marine's suit of Power Armour is so specific to its wearer that it cannot be worn by 2 different Space Marines without alterations. So precious is his ancient suit of armour that each Space Marine swears solemn oaths to honour and maintain its individual Machine Spirit and the memories of all the honoured Astartes who have worn that particulalr suit over the generations.
=== Terminator Armour ===
Tactical Dreadnought Armour, more commonly called Terminator Armour, turns an Astartes into a nigh-unstoppable force of destruction. These exceedingly rare suits of Power Armour are the superlative form of individual protection in Space Marine Armouries, and enable a Battle-Brother to unleash firepower rivalling that of most combat vehicles. Developed during the final days of the Great Crusade, the Imperium has long since lost the technical knowledge required to manufacture these suits, and so every single one is a priceless artefact of the Imperium's lost Golden Age. Terminator Armour is only deployed on the most dangerous missions and only to Astartes Veterans who have proven themselves worthy of wearing the Crux Terminatus: the icon found on the left shoulder of every suit of Terminator Armour. Each one of these honour badges is said to contain a fragment of the Emperor’s own armour from his final battle with the traitor Horus during the Battle of Terra. 
Terminator Armour was developed for a mid-range of uses between a true cybernetic Dreadnought and standard Power Armour. It is composed of a Ceramite/Plasteel alloy exoskeleton with servo-assisted interfaces that link into the user's own neurological and muscular systems to enhance movement. Terminator Armour’s heavy layers of protective alloys can deflect even the heaviest bombardments. In addition, the Crux Terminatus on every Terminator’s shoulder plate serves as a psychic ward capable of turning aside attacks from Power Weapons, Melta fire, and even the baleful energies of the Warp. It is able to withstand tremendous punishment, and serves as a solid heavy-weapons platform in open-field combat. Due to its size, it is best deployed in close quarters such as the corridors of a starship, where the armour's standard-issue Storm Bolter can be most effective. The elite 1st Company of each Space Marine Chapter uses Terminator Armour, and only those Astartes who have earned the "Crux Terminatus" are permitted to wear this precious and irreplaceable piece of Imperial technology.
=== Artificer Armour ===
Artificer Armour is the name given to individualised and heavily modified suits of Power Armour provided only to Space Marines who have proven themselves worthy of the honour, such as company Captains, members of the Chapter Master's Honour Guard, or particularly skilled Veterans of the 1st Company or the various company Command Squads. Painstakingly cared for and customised for each esteemed bearer, Artificer Armour is the rarest form of Power Armour, even more so than Terminator Armour. The technology and superdense materials used to construct these suits is unparalleled inside the Imperium. Each one is a masterwork of Artificer ingenuity and (outside of Techmarines labouring towards their own) is awarded only to true Chapter heroes. Artificer Armour is always Master-Crafted. In addition to the effects of standard Astartes Power Armour, the advanced helmet incorporates a Mind Impulse Unit (MIU) similar to those used by the members of the Collegia Titanica to control their massive Titan war engines. Some suits incorporate even more unusual features, such as automated fibre re-weaving, eliminating the need for Repair Cement to seal most breaches in the armour after combat. Only countless hours of labour at the blazing Space Marine forges by a Chapter's Artificers or Techmarines gives rise to a suit of Artificer Armour. It is said that Artificer Armour can almost provide the equivalent protection as Terminator Armour. Artificer Armour cannot, however, make use of weapons as powerful as those available to Astartes in Terminator Armour
== Forces of the Space Marines ==
=== Commanders ===
==== Chapter Master ====
To be a Chapter Master (some Chapters use other titles for their commanding officers) of the Adeptus Astartes is to be as a stern but kindly Angel of Death among men, as the Emperor is their God. A Chapter Master's personal combat prowess is unmatched, for his body is that of an Astartes, with hundreds of years of battlefield experience as a Scout Marine, Battle-Brother, Sergeant and finally as the Captain of a Chapter company. These experiences have taught him every facet of war, trained him in the tools of combat and honed his quick thinking to the level of primal instinct. Ranked high among the greatest heroes of the Imperium of Man during these dark days of what many fear are the End Times are the Chapter Masters of the Space Marines. Even in the 41st Millennium, a time of constant warfare between combatants like no others in human history, there are few amongst humanity's defenders that can claim such honour and renown as they, for in sheer scope of battles won and foes vanquished, the Masters of the Space Marines have no peers save among the dead heroes of the past. With the merest glance, a Chapter Master can appraise a warzone, can see every threat and opportunity presented by the shifting lines of battle and then determine how victory can be won for the Imperium. 
A Chapter Master stands firm where other men falter, advances without fear when other men flee and retreats when only a true incompetent or someone in search of a fool's death would fight on. By his example he inspires other men to their greater valour, not only the Space Marines under his command, but also Imperial Guardsmen and the Planetary Defence Force militia who often fight besides the Astartes. If a Chapter Master's personal might in the crucible of combat is unmatched, then the wider political power he wields is nothing short of epic. A Chapter Master is a noble peer of the Imperium, with the legal authority granted by the High Lords of Terra to act as he wishes according to his own judgment and answerable only to others of his rank among the Astartes. Even the Inquisition treads lightly around the Masters of the Adeptus Astartes. In addition to the thousand Space Marines at his command, most Chapter Masters also hold authority over star-spanning Battle Barges, Strike Cruisers, Navigators, Astropaths, Armourers and Planetary Defence Forces. Indeed, most Chapter Masters rule entire worlds, systems or even subsectors of space in the Emperor's name as Imperial Governors and Imperial Commanders in their own right. Such places are zones of relative prosperity and stability in a galaxy riven by war, their potent defences girded by the inestimable strength of a Space Marine Chapter and the political patronage of its Master. 
The Adeptus Astartes have access to some of the most powerful and rarest vehicles in the Imperium. They are all treated as holy relics, and lovingly maintained by the Chapter's Techmarines. Many vehicles are ancient STC designs, barely understood by the current knowledge available to the Adeptus Mechanicus.
==== Honour Guard ====
Veteran Space Marines with centuries of service and multiple commendations and decorations are sometimes awarded the chance to serve in their Chapter's Honour Guard. Every Astartes in a Chapter Honour Guard have proven themselves to be living exemplars of the Space Marine ideal that the Primarch Roboute Guilliman laid out in the Codex Astartes. Honour Guards are stoic and spiritually solemn individuals when at rest in their Chapter's fortress-monastery, but ferocious and unyielding in battle. Each has received the very highest honours that his Battle-Brothers can bestow, performing deeds the likes of which lesser men can only dream. Indeed, it is said that each member of a a Chapter's Honour Guard has earned more commendations and glories in a lifetime's service than a whole company of Space Marines from any other Chapter, and that each individual has slain more foes than an entire regiment of Imperial Guardsmen. So steeped are the Honour Guard in the art of war that their understanding of tactical and strategic combat commonly outstrips even the experience of the Chapter's company Captains. It is considered folly for even the Master of the Chapter to ignore the counsel of his Honour Guard. The most skilled member of the Honour Guard is usually selected as the Chapter Champion, whose duty it is to challenge any enemy commander to single combat. When this is not possible, the Champion directs all his effort in battle to killing the most elite individual enemy commanders to damage the opposing force's morale. An Honour Guard's wargear is drawn from amongst the most ancient relics of the Chapter, for such men above all others have earned the right to wield such weapons and bear the burden of leadership that accompanies them. Thus, it is common for a Chapter's Honour Guard to wear Artificer Power Armour and wield masterwork versions of standard Astartes weapons. Most Space Marine Chapters have only a handful of Honour Guard, enough to form a distinct and capable fighting unit surrounding the Chapter Master, but no more. A few of the older and larger Chapters like the Ultramarines can muster as many as two dozen Honour Guards, but it is rare even for them to fight as a unit. When in combat, the Honour Guard acts as the Chapter Master's bodyguard, responsible for the safety of their commander and hoisting aloft the Chapter's battle standard. These are sacred tasks and the Honour Guard fight for both ferociously, and never succumb to fear or rage which may cloud their judgment. Such courage and devotion has been the salvation of more than one Chapter Master's life. When a member of the Honour Guard is slain, his Battle-Brothers will take any action necessary to recover the body so that his gene-seed may be returned to the Chapter and his remains can be interred with full honours in the Chapter's Vault of Heroes.
==== Space Marine Captain ====
Each of the 10 companies in a Space Marine Chapter falls under the command of an officer called a Captain. Each Captain is a hardened Veteran, a master strategist who has proven his prowess in battle as a member of the Chapter's elite 1st Company, or through distinguished service in his own company as a squad sergeant prior to the death of his predecessor. In addition to his Chapter rank, each Captain also bears one or more honorific titles associated with the command of a particular company or responsibility. Some, such as Master of the Watch and Master of the Recruits, are common titles in use across almost all Space Marine Chapters. Other titles are products of a particular Chapter's history, culture and military specialties. The Captain of the White Scars' 4th Company is traditionally the Master of the Hunt, while the Aurora Talons Chapter, specializing in space warfare, maintains no less than five Master Bombardiers among their company Captains. Individual Captains can also be assigned to command missions that require the deployment of elements of the Chapter beyond their own company. In these situations an individual Captain takes on the temporary rank of Force Commander and gains precedence over even other Captains assigned to this mission. It is not enough for an Astartes Captain to be a skilled warrior - each Chapter boasts many such men amongst its roster - he must also have a superhuman grasp of military strategy and combat tactics, as well as the intelligence to employ them in the ever-changing arena of warfare. It is commonly said in the Imperium that in terms of raw military might, every Space Marine is easily worth a dozen or so Imperial Guardsmen. Under the command of an experienced Captain, this value can swell tenfold. A Space Marine Captain is not simply a master of warfare, he must also have the gift of diplomacy and political adroitness. While most Imperial Planetary Governors and Commanders are more than happy to receive aid from the Space Marines when in trouble, there are those whose arrogance must be carefully negotiated in order to prevent a battle's collapse into a true disaster for the broader Imperium through unnecessary political infighting. This is not to say a Space Marine Captain lacks for ultimate authority when dealing with hubris and failure to the Emperor -- as Captain Kayvaan Shrike of the Raven Guard's 3rd Company once proved by executing a vacillating Lord Cardinal Dostok on the spot. That said, subtler methods of diplomacy are best employed in grim situations -- the necessary punitive measures can be enacted after the threat has been ended. A Space Marine never bends the knee lightly to any non-Astartes, but the needs of the Emperor's realm must override any personal feelings. The mission is always all. Humanity shall be saved from its own petty failings, even if this must be done one world at a time.
In addition to the command of an entire company, it is common for Space Marine Captains to hold a variety of other formal titles and functional duties within the Chapter. The following is a list of the most common formal titles held by Space Marine Captains in a standard, Codex Astartes-compliant Chapter: 
* Lord Executioner - The Lord Executioner is the captain who serves as the master of the Chapter's Assault Company. He is a brutal and direct individual, not so much given to glittering heroics and flamboyant challenges as short, bloody and efficient close combats. Clutching his favoured master-crafted melee weapon in his hands, he strides purposely forward in battle, the expression of a stone cold killer writ on his face as he heads towards his grim duty. His Artificer Armour is often impressively detailed with embossed skulls, scrollwork and multiple Purity Seals. Of all the Space Marine Captains within a Chapter, the Lord Executioner is the most menacing. 
* Master of the Marches - As well as leading an entire company of Space Marines in battle, the Master of the Marches has the duty of overseeing the deployment of the Chapter's fighting strength. It is his knowledge of Chapter dispositions the Chapter Master turns to when readying for war. The Master of Marches is wholly devoted to his duty as he gazes at a massive length of parchment held aloft by a Cyber-cherub, which contains critical data. Upon his backpack are twin Vox-casters which are utilised to project orders across the noisy battlefield. 
* Master of Relics - The Master of Relics is the commander of the Chapter's Devastator Company, an unmatched expert in the tactics of long-ranged warfare. He is also the custodian of the Chapter's many technological masterpieces, the most dangerous of which are brought to the battlefield in times of exceptional strife. The Master of Relics is often clad in ancient patterns of Power Armour, and armed with an impressive array of master-crafted weapons from the Chapter's armouries. He projects an aura of stoic watchfulness as he directs a withering look upon distant foes. On his backpack is a targeting array which matches the angle of his gaze, gathering telemetry information to be fed to his Devastator Marines. 
* Master of Rites - The Master of Rites is charged with recording and preserving the martial traditions of the Chapter -- a bombastic, courageous warrior with unswerving loyalty to his Battle-Brothers. This individual exudes a sense of martial pride and fervour to those around them. A large Servo-skull with an incorporated Vox-caster that amplifies his warcries is anchored near his feet by a weighty pair of censers. The Master of Rites roars inspiring rhetoric during the heat of battle, reminding his Battle-Brothers to remember their duty and heritage, even as they clash with the foe. 
* Master of the Fleet - The Master of the Fleet is that Space Marine Captain who is deemed to have the most experience and greatest skill at planning and executing void-combats. He is given command of the Chapter fleet, and essentially serves as the Chapter's fleet admiral, commanding its flagship and all other space assets when they deploy for major engagements. In rare cases, a Chapter's Master of the Fleet may not be an Astartes officer but a mortal with a long history of space combat and commanding fleet engagements, such as a former or current command officer of the Imperial Navy who has been seconded to the Chapter under ancient inter-service agreements. 
* Master of Recruits- The Master of Recruits is the officer who is responsible for training all of the Chapter's Neophytes and who usually also serves as the commander of the Chapter's Scout Company. He will be a skilled Veteran of hundreds of battles and a shrewd judge of character, easily able to determine what will bring out the best in the genetically-altered adolescents who survived their Aspirant Trials and transform them into true Astartes. As the leader of a Scout Company, the Master of Recruits will be an expert in the irregular forms of combat that define the missions of Space Marine Scouts, including sabotage, infiltration and counterinsurgency.
==== Librarian ====
The Imperium of Man is eternally vigilant for the taint of mutation in its citizens, as mutation of the perfect human form is a terrible heresy against the will of the Emperor. The Chapters of the Adeptus Astartes are, if anything, even more careful to ensure that their gene-seed is not polluted. Apothecaries rigorously screen potential recruits for any sign of genetic deviation, but not all mutation presents itself in a purely physical manner. Psychic talent is a mutation too, and is at once the most dangerous and the most useful. Detecting and developing nascent is one of the many responsibilities of a Chapter's Librarium. Very few normal Space Marine recruits survive the rigorous training, genetic enhancement and indoctrination. Amongst , this level of attrition is far worse. Not only must the recruit endure everything a normal recruit would, but he must be strong enough in spirit to withstand the moulding of his mind. A recruit must be taught how to hone and wield his powers, and how to protect himself from the perils of the Warp. A Librarian faces a thousand enemies before he ever goes to war - to the creatures of the he is a choice prize, with sorcerous aptitude and strong flesh to contain a daemonic essence. If a recruit survives the testing he joins the Chapter Librarius as Lexicanium, rising through the ranks to become Codicier, Epistolary or perhaps even Chief Librarian. He will use his abilities to pierce the Warp, provide the means for interstellar communication and identify more of his own kind. A Librarian's talents set him apart from his comrades - after all, a Librarian wields abilities that every Space Marine is normally expected to abhor - yet their presence is always welcomed on the field of battle. Most Librarian battle-disciplines focus on strengthening and enhancing his already formidable combat prowess. He can unleash powerful energy bolts, prevent enemy machines from functioning, project force shields, increase his strength to near godlike proportions or even eliminate the barrier between the Warp and the physical realm, unleashing a devastating miniature Warp Storm. Even so, the most skilled Librarians can master more subtle and even more potent psychic gifts. Some can step outside the confines of linear time, sense the enemy's movements or redirect bullets with the power of their mind. In all of the Imperium there are few greater warrior-mystics, combining the prowess of the Adeptus Astartes with the steel discipline needed to contain and control their sorcerous powers.
==== Master of the Forge ====
The Master of the Forge is a Chapter's most senior Techmarine, charged with the maintenance of the Chapter's fleet of armoured fighting vehicles, such as Rhinos, Land Raiders and Predators. His knowledge of the arcane sciences has been refined over centuries of service, and rivals that of the senior Tech-priests of the Adeptus Mechanicus of Mars. The Master of the Forge is so skilled that he can tell what is wrong with a vehicle's Machine Spirit at but a glance. Such skills conspire to make the Master of the Forge something of an outcast in most Space Marine Chapters. Though he is always part of the Chapter Council, the Master of the Forge is an outsider to all save his subordinate Techmarines, whose company is shunned in all matters save those that pertain to his beloved mechanicals. 
Not all Space Marine Chapters treat their Master of the Forge in this way. Some, such as the Mentors, the Praetors of Orpheus and the Astral Knights, embrace the dwindling advanced technologies of Mankind without the usual superstition and, in the case of the Iron Hands, with an enthusiam nearly matching the Mechanicus. In these Chapters, the Master of the Forge is a personage honoured no less than the Chapter Master himself. Such cases are not common among Astartes. Indeed, for one Chapter to embrace the vision and purpose of a Master of the Forge is to invite suspicion from many of its more conventional brothers. In addition to his responsibilities to maintain the Chapter Armoury, a Master of the Forge is also tasked with the conservation of any arcane technological artefacts to which his Chapter is heir. The oldest and most famous Astartes Chapters have many such technological wonders from the time before the Horus Heresy locked within their Armoury's vaults. Like the other Techmarines who serve under him, the Master of the Forge is equipped with powerful bionic servo-arms called Mechadendrites that can be used for battlefield repairs or even put to use as another weapon. Masters of the Forge also sometimes wield an ancient pre-Heresy weapon called a Conversion Beamer, whose projectors fire a beam of anti-matter that induces a controlled subatomic reaction in the target, converting its mass into energy. The further away the target, the more deadly the blast, as the beam has time to grow in power.
==== Chaplains ====
Chaplains are the spiritual leaders of a Space Marine Chapter. They administer the rites, preserve the rituals and perform the ancient ceremonies of Initiation, Vindication and Redemption that are as important to a Space Marine Chapter as its roll of honour and skill at arms. Chaplains are daunting figures even for other Space Marines to behold. Their Power Armour is jet black and adorned with icons of battle and tokens of ritual and mystery; their skull helms are white, skeletal death masks that evoke the stern visage of the immortal Emperor decaying upon the Golden Throne. Every aspect of a Chaplain's garb serves to remind all who gaze upon him of the mortality that faces all Men and thus the importance of preserving the immortal soul. Beneath this stern visage is a man no less grim of aspect and manner. Chaplains are notoriously strict individuals. They are responsible for the spiritual well-being of their Battle-Brothers and renowned for their sense of duty. 
A Chapter's Chaplains are the keepers of the Reclusiam, the fortress-monastery's central shrine where prayer and worship is conducted. The Reclusiam is a place of great spiritual reverance, where battle standards hang from hallowed walls and the very stones echo with remembrance. Here are kept the Chapter's most holy relics: fragments of armour, Chapter banners from battles of legend, and the weapons of ancient heroes who long ago passed beyond the veil. Space Marine Chaplains care nothing for the ravings of the Ecclesiarchy and ignore the dictates of the Imperial Cult in favour of their Chapter's own ancient traditions, though they often carry a Rosarius as a symbol of their faith in the Emperor like the priests of the Ministorum. The first Space Marine Chapters were founded many centuries before the development of the Imperial Cult and the dominion of the Adeptus Ministorum over the Imperium. Whereas the Adeptus Ministorum has gradually extended its influence over the many thousands of individual cults of Emperor-worship that once existed throughout the galaxy, it has never been able to influence the cults of the Astartes, which remain as stubbornly individualistic today as they ever were in the past. When war calls, a Chaplain fights wherever the conflict is fiercest, leading from the front and rejoicing in the slaughter of the enemy as one doing righteous work, punctuating his praise for the Emperor with strikes from his Crozius Arcanum - the skull-headed staff that is both a badge of office and his chosen weapon of war. By his example and his piety, the Chaplain exhorts his Brother-Marines to the pinnacle of dedication, so that they might conquer with valour that which would resist all else.
==== Command Squad ====
A Command Squad accompanies high-ranking Space Marine officers, usually company Captains, on the field of battle. The exact nature and title of a Command Squad's members can vary, depending on a Chapter's organisation and the personality of a company's Captain. The most common members of a Command Squad are the Company Champion, the Company Apothecary and the Company Banner Bearer, and these Astartes can be found in almost all Command Squads. Even so, some Space Marine Chapters prefer other titles and positions for a Command Squad in accordance with their traditions, such as the Foeseekers of the Omega Marines, the Prognosticars of the Silver Skulls, the Terrorblades of the Death Spectres and the Pyre Wardens of the Fire Lords. 
Company Banner Bearers carry the battle-flag of the company in which they serve. Each standard is an ancient artefact, steeped in the history and the traditions of the Chapter. The company banner is the physical heart of the company on the battlefield, and every Space Marine, from the most inexperienced Scout Marine to the most skilled Veteran of the 1st Company, fights all the more valiantly when it is within sight. The Banner Bearer is trusted never to let the standard out of his grip while he still draws breath - to do otherwise is to invite the most terrible and shameful dishonour on both his company and the Chapter as a whole. 
The Apothecary is well-versed in the arts of combat first aid and triage as well as the more advanced arcane sciences of surgery, cybernetics and bio-engineering. He must also be a warrior of untold might and courage, for his place is in the bloody heart of battle. If an Astartes falls, the Apothecary can use his advanced biomedical aid kit, his narthecium, to tend the wounds, allowing his Battle-Brother to return to combat even after suffering grievous wounds. Yet some weapons are terrible enough to mortally wound even a superhuman Astartes. The Apothecary can then only calm the mind of the dying Astartes and prepare him for his eternal reward at the feet of the Emperor. Once dead, a Space Marine can live on through his gene-seed, as the Apothecary uses his reductor to remove the progenoid organs from the slain Astartes' corpse. From the genetic material held within these precious organs, the creation of new Space Marines and thus the continuation of the Chapter is assured. 
Company Champions are charged with defending the honour of their company, their Chapter and the Emperor himself. They engage the the greatest warriors and commanders of the enemy in single combat, leaving the company's Captain free to command the wider battle, rather than engage in a series of personal combats. Most Company Champions have key roles in the rituals and ceremonies of the Chapter, representing the Battle-Brothers of their companies in the Chapter's rites and rituals as honourably as they defend them on the field. Service in a Command Squad speeds promotion within the Chapter as most Captains fill their Command Squads with Astartes whose skills in combat are equaled by their demonstrated strategic intelligence. Captains and their Command Squads can invariably be found where the fighting is thickest and so a company Captain's successor is often named from among those Astartes of his Command Squad who have proven themselves again and again against the most terrifying foes of the Emperor.
=== Elites ===
==== Terminator Squads ====
All Space Marine Chapters maintain a number of suits of the revered and rightly feared Tactical Dreadnought Armour, or Terminator Armour as it is more commonly known. Suits of Terminator Armour are the pinnacle of armoured protection available to a Space Marine. Each is all but impervious to small arms fire and can even withstand the merciless onslaught of tank-busting Krak Missiles. Terminator Armour is incredibly rare in the Imperium and is no longer manufactured by the Adeptus Mechanicus. Space Marines hold it a great honour to be permitted to wear such a suit in battle, and it is only the members of a Chapter's elite 1st Company who gain this honour. Once trained in the use of Terminator Armour, a Space Marine is counted as the first among equals and is expected to conduct the most difficult of missions and to perform beyond even the already lofty standards of the Astartes. Boarding Tyranid-infested Space Hulks, launching teleporter attacks, Titan assaults and combat actions in extremely hostile environments, such as deep space or volcanic marshland; these are the missions undertaken by Space Marine Terminators. No foe is safe from a Terminator assault, not a horde of Orks, adamantium fortress or even a colossal Chaos Titan. The left shoulder plate of a suit of Terminator Armour carries the large solid stone icon known as the Crux Terminatus. This doubles as a tactical symbol and as a revered honour badge of the Astartes. Each Crux is reputed to have bound within its core a tiny fragment of the battle armour worn by the Emperor himself in his epic duel with Horus 10,000 years ago during the Battle of Terra. The design of this ancient badge can vary considerably, even within a single unit or Chapter. Sergeants' and Officers' Crux tend to be more elaborate and finely detailed than those worn by normal Battle-Brothers, but all are venerated equally. To lose even a single Crux in battle is to betray the Emperor's trust and bring great shame down on the entire Chapter.
==== 1st Company Vanguard Squad ====
Of all the fighting formations that make up a Codex Astartes-compliant Space Marine Chapter, it is the 1st Company which is most feared. For an Astartes to join the 1st Company is for him to have won renown on battlefields uncounted and to have earned the respect of his Battle-Brothers through deeds of blood and honour. Most such Veterans have served as Sergeants elsewhere in the Chapter -- sometimes for centuries -- before being accepted into the 1st Company, but a notable few are elevated after performing insane acts of heroism. Every member of the 1st Company is proficient in all manner of Astartes weaponry and stands as a living exemplar of the ideals and purpose of the Chapter. With such status comes the right to select weapons of choice from the Chapter's Armoury and, as a result, Veterans Squads are much less rigid in composition and doctrine than other Space Marine formations. They are often equipped and ordered to undertake highly specialised missions that can prove to be force multipliers, such as slaying an Ork Warboss and his bodyguard of Nobs or preventing a wave of Eldar Aspect Warriors from joining the main body of an enemy Eldar force. Vanguard Squads are formed from those members of the 1st Company that completely immerse themselves in the art of close-quarter combat. Most have completed lengthy service rotations in their Chapter's Assault Squad, their skills tested and honed in the crucible of bloody melee on a thousand thousand worlds. Power Swords, Plasma Pistols and Power Fists are all common sights in Vanguard Veteran Squads, and Thunder Hammers, Lightning Claws and rarer weaponry are also employed as the engagement requires. These weapons are not employed lightly, for they are without exception ancient and revered artefacts of the Chapter. A Vanguard Veteran who returns from the field of battle without his armament is subject to the Chapter's gruelling rites of penance. Whilst they can be deployed at the forefront of an assault, most Chapters employ their Vanguard Veterans as rapid-response forces, using Jump Pack or Rhino transport to apply crucial pressure to an already over-taxed enemy defence, or to reinforce overmatched allies. Often referred to as a Captain's "Iron Fist," Vanguard Veterans are constantly in motion.
==== 1st Company Sternguard Squad ====
Sternguard Astartes Veterans of the elite 1st Company deploy wherever the battleline is most vulnerable, facing down the most impossible odds with icy calm and precise bursts of Bolter fire. They are the very image of what every Space Marine aspires to become, and the pinnacle of any Chapter's fighting force. In contrast to the Battle-Brothers of the 1st Company's Vanguard Squads, Sternguard Veterans draw upon the Chapter Armoury's ranged weaponry. The squad's sergeant will sometimes wield a specialised melee weapon, but this is the extent to which a Sternguard Squad will employ close combat weaponry. Most Sternguard Veterans carry Bolters with meticulously crafted sights and modified scopes. Heavier weapons are also available, such as the Missile Launcher and Lascannon, but these are normally eschewed for the more portable Bolter. Any potential shortfall in firepower is compensated for by the range of specialist boltgun ammunition a Sternguard Veteran can carry into battle, including unstable flux core Vengeance rounds for heavily armoured targets, propellant-rich Kraken Bolts for extended-range engagements and the acidic fury of Hellfire Rounds for bringing down even the angriest Greenskin or Tyranid monstrosity. In most Chapters there is a rivalry of sorts between the Vanguard and Sternguard halves of the Veteran 1st Company. These factions compete endlessly for honours and hazardous combat duties - the glories and shames of their adherents celebrated and atoned for by all. Despite this innate rivalry, Vanguard and Sternguard Veterans remain Battle-Brothers above all else, and fight unto death for one another.
==== Techmarines ====
Ancient pacts sworn between the Adeptus Mechanicus and the Adeptus Astartes allow the Space Marines to send those warriors with an affinity for technology to Mars to train and begin the long, arduous journey of becoming a priest of the Machine God. Without the passing on of such ancient technological lore, the Space Marines would be unable to make war. Aspiring Techmarines train for many years on Mars, steeping themselves in rites of activation and hymnals of maintenance; how to call forth a Machine Spirit or placate its wrath. Techmarines return to their Chapter as aloof and mysterious figures steeped in superstitious awe. From that point forth they are men of dual loyalties, pledged by blood to their Chapter, but bound in mind and spirit to the mysteries of the Mechanicus' Omnissiah. This dichotomy ensures that a Techmarine is never again truly trusted by his brothers and is kept at arms length from the Chapter's secrets and rituals. Despite this suspicion, Techmarines are held in great esteem by their Battle-Brothers who recognise and acknowledge the Techmarines' expertise in the mysterious arcane sciences. A Space Marine Chapter would be of little consequence without its many technological tools, and its ancient weapons must be kept in a constant state of readiness - without the Techmarines this would be impossible. Despite their arcane calling, they are warriors first and foremost. Should a vehicle or artefact of technology be lost, the Techmarines will fight for its retrieval as stridently as their brethren would fight to recover a fallen comrade; perhaps, like their Tech-priest counterparts, even harder.
==== Servitors ====
Servitors are single-task, mindless cyborg slaves that exist solely to assist a Chapter's Techmarines in their laborious duties. Each is an arcane combination of man and machine, without personality or reason, sporting an array of mechanical modifications ranging from huge metal claws and infra-red sensors to bionic exoskeletons and flux-torsion drills, all the better to aid a Techmarine in his repair and maintenance of a Chapter's Armoury. Some Servitors are even bonded to heavy weapons so that they may act as battlefield bodyguards of their master. The creation mysteries for Servitors vary from Chapter to Chapter. Some are grown from human gene-cells in artificial nutrients and have their machine components grafted onto them after they are decanted. Others are failed Neophytes, civilian Imperial criminals or fugitives from Chapter law who have been mind-wiped and lobotomised so that their flesh may continue to serve the Emperor's purpose. Although physically strong and robust, Servitors are not sentient and can only function at the command of the bioprograms that Techmarines insert into their brains. They feel little pain, no fear and have no intuition whatsoever. Without a Techmarine's constant supervision, Servitors are erratic at best - most go into a state of mindlock, babbling incoherent nonsense as their ravaged brains try to assert some form of awareness. Nonetheless, a Space Marine Chapter relies heavily on its Servitors to maintain its weapons of war. Hundreds of biomechanoid slaves toil ceaselessly deep within the walls of every Chapter fortress-monastery, preparing and maintaining weapons of war. 
Though essential to the maintenance of a Chapter's mechanical devices and fleet of starships, Servitors rarely enjoy anything save indifference from the Astartes they serve. In most Chapters, the Servitors are ignored by all but the Techmarines, treated as one would any other machine or piece of equipment. In others they are treated with revulsion, considered necessary abominations that pervert the spirit and the flesh of Man. Conversely, in a very few Space Marine Chapters, generally those with strong ties to the Adeptus Mechanicus like the Iron Hands, Servitors are regarded as having achieved a spiritual union with the Omnissiah. In such Chapters, Servitors are treated as cybernetic shrines, revered almost as greatly as other technological artefacts, their laconic words sifted and analysed for hints of prophecy and guidance from the Machine God. Those Space Marines who follow these arcane practices believe that in so doing they are brought closer to the Omnissiah. To other Chapters, such behaviour is thought distasteful to the point of heresy and regarded with hostility and suspicion. What the Servitors think of all this - if indeed they are even capable of thinking - none know.
==== Dreadnought ====
When a Space Marine suffers grievous harm, the like of which even his superhuman physique cannot endure, his ravaged body is borne from the battlefield with great reverence. Most such men die swiftly of their wounds, or receive the Emperor's Mercy from one of the Chapter's Apothecaries. Their lifeless forms are cremated, interred or sent to journey the infinite void, according to the traditions of the Chapter. But the greatest of Space Marines who fall in battle with grievous and often life-threatening wounds that cannot be repaired using standard bionics or medicae treatments are placed into a cybernetic Dreadnought shell that allows the interred Astartes to continue to live through a sophisticated array of life support machines. The pilot of the Dreadnought is hooked straight into the Dreadnought's systems to preserve him and allows the crippled Space Marine to control the Dreadnought as if it were his own body. The hero's crippled body is installed in the cyborganic web of an armoured sarcophagus, his dimmed senses bound to electro-fibre implants. It is a great honour to be deemed worthy enough by one's Battle-Brothers to be interred in a Dreadnought so that one can keep fighting in the Emperor's name for many more millenia, as the knowledge to create new Dreadnought shells has been lost over the long centuries. Some Marines that have been placed in the great Dreadnoughts have been around since the Emperor himself still walked among his people during the Great Crusade. When the Dreadnoughts are not needed by the Chapter, they are placed back into the Chapter's chapel to sleep away the centuries until they are needed once more. 
Many an assault commences with a wave of Dreadnoughts to first drive a wedge through the enemy's defences. A Dreadnought is a truly massive fighting machine, weighing several tons and standing two or three times the height of a man. As the Dreadnought strides purposefully into battle, incoming fire spatters like rain off his towering adamantium and ceramite hull. Fiery death roars from his weapons and his great metal arms churn through all who are foolish enough to stand before him. Actual weapon loadout varies from Dreadnought to Dreadnought and the needs of the mission. The close support pattern of Assault Cannon and Power Fist is by far the most common Dreadnought configuration, although the tank-hunting Lascannon or bunker-breaching Multi-Melta and Seismic Hammer combination are equally fearsome. Needless to say, the hero that guides the armoured cybernetic hulk is more than proficient in all the many weapons and tactics employed by the Space Marines. 
A Dreadnought's raw power is made all the more deadly because it is wielded with all the grim resolve of the mortally wounded Veteran Astartes bound in its core, and directed by centuries - or even millennia - of experience. The memories of these powerful Venerable Dreadnoughts can extend back thousands of years to the founding of their Chapter and its earliest history. Thus they are revered by other Space Marines, not just as potent warriors, but also as ageless forebears and as a living embodiment of battles fought long ago. Dreadnoughts are not seen merely as formidable weapons of war, but as keepers of tradition and custodians of knowledge whose advice is sought by Initiate and Chapter Master alike. It is not unknown for Dreadnoughts to serve as members of the Chapter Council, lending wisdom to strategy as they do fury to the battlefield. Dreadnought shells are amongst the most prized of a Chapter's relics. Should a Dreadnought fall in battle, his brothers will fight with righteous anger to retrieve the shell so that they may lay its occupant to rest with honour and reclaim the shell to house another dying hero who will become an Old One to future generations.
==== Ironclad Dreadnought ====
The Ironclad Dreadnought is a specialised variant of the standard Imperial Dreadnought combat walker that is used by the Chapters of the Adeptus Astartes. Dreadnoughts are cybernetic combat walkers that house the mortal remains of a fallen Space Marine hero so that he may continue fighting for the Emperor and his Chapter even after his body has been fatally crippled. Dreadnoughts are classified in several different ways, the most common of which is simply by their armament. Standard Dreadnoughts are equipped with a long-range weapon such as an Assault Cannon in place of one of their arms and their other is tipped with a Dreadnought Close Combat Weapon, such as an enlarged Powerfist. The Ironclad Dreadnought variant was designed for heavy close-combat fighting and siege warfare similar to the Siege Dreadnought, yet the Ironclad Dreadnought is more commonly found in Space Marine armouries. Ironclad Dreadnoughts sacrifice versatility and firepower for an even greater amount of armoured protection and powerful, dedicated siege weaponry, and while they may not be as effective as the Siege Dreadnought in close-quarters, street-to-street urban combat, they more than make up for it by way of their powerful close-combat weaponry and extreme durability.
==== Legion of the Damned ====
The haunting legend of the Legion of the Damned is known across the galaxy, and even nonbelievers speak of such things in hushed tones. These silent warriors are Space Marines in appearance, their black armour adorned with images of bones and fire, yet they are not of any Chapter recognised in the Imperium. Most eyewitnesses dispute even the Legionaries' mortality, for an eerie glow suffuses their sable armour and a halo of ghostly fire dances about their feet. There are many corroborated accounts of Legionaries enduring firepower that would annihilate mortal men. Among them is a report from the Keyan battle zone, where a handful of Legion of the Damned were witnessed walking unharmed from the Volcano Cannon blast that claimed four Predators and several squads of Space Marines. The Bolters carried by the Legionaries, though in aspect no different to those borne by other Space Marines, discharge flaming projectiles that can pierce the strongest armour. Nothing, not Chaos Chosen, rockcrete bastion, nor boiling lava can stay the spectral wrath of the Legion of the Damned. 
The nature and origin of the Legion of the Damned is shrouded in mystery and myth. Some rumours suggest that they are the survivors of the lost Fire Hawks Chapter, transmuted by the Warp Storm that claimed their vessel. Others imply that the Legion are an extension of the Emperor's will, time-lost saviours, or even the vengeful spirits of Space Marines slain in the Imperium's many wars. In the course of their investigations, several Inquisitors have tried to capture or intercept the Legion of the Damned, but all have failed; events always inexplicably conspire to prevent the Inquisitors from getting close to their quarry, leaving them nothing more than frustrated witnesses to the event. 
Who, or what, guides the Legion of the Damned is an enigma to all save the beneficent Emperor Himself. They appear only in times of great need, coalescing from the fires of a desperate battlefield to turn a disaster into victory. Regardless of the conflict, the Legionaries fight with a chill precision that few mortal warriors can match, sweeping enemy positions like vengeful ghosts. Terror is their harbinger and oblivion their gift. After the battle, the Legion of the Damned depart as suddenly as they arrived, leaving only the bodies of the slain and wonder in their wake.
==== Centurion Assault Squad ====
A Centurion is a Space Marine who has been equipped with a powered exoskeleton worn over his normal suit of Power Armour known as a Centurion warsuit that allows him to serve a heavy ranged or close combat assault role between that of a normal Astartes and a Terminator. A Centurion warsuit enables a Space Marine to stride into battle with the firepower of a battle tank at his fingertips. Protected by thick ablative plates of ceramite, a Centurion warsuit renders its pilot immune to all but the most powerful of weapons. Named after the Space Marine Legion leaders of old, the Centurion warsuit design was unearthed in the aftermath of the Age of Apostasy in the 36th Millennium, and after sanction by the Adeptus Mechanicus, the suits found their way into the armouries of almost every Space Marine Chapter. 
Centurion Assault Squads excel at storming enemy fortifications and advancing through the broken and crumbling terrain of an embattled city. They eschew long-ranged weapons completely, favouring close-range firearms and Flamers that they use for flushing enemies from cover. Instead of heavy guns, they wield Siege Drills -- heavy-duty tools of destruction that can swiftly shatter a building to rubble, tear a breach in a strong point's adamantium-reinforced walls or reduce a living opponent to a bloody mass of broken bone.
=== Troops ===
==== Tactical Squad ====
Tactical Squads are the backbone of any Space Marine force. They are called upon to fulfill the full range of combat roles; they hold ground, provide fire support or charge into the bloody melee of close combat, as the ever-changing theatre of battle dictates. For an Astartes to be assigned to a Tactical Squad he must have proven himself beyond doubt in all aspects of war. So it is that a Space Marine must complete several campaigns in both Assault and Devastator Squads before he can earn a permanent position in one of the Chapter's Tactical Squads. This progression must be earned in blood and can last for years, or even decades, depending on the skills of the Space Marine in question. Not all Space Marines make the transition. Some demonstrate a talent or obsession for a particular aspect of battle that, while immensely valuable in its own way, would prove a liability in the adaptive role of the Tactical Squad. Other Battle-Brothers simply lack the mental flexibility to embrace the fluidity of the Tactical Squad's role. As befits its varied battlefield role, a Tactical Squad takes to the field with a wide variety of weaponry. In addition to the standard Space Marine armament of Bolt Pistol and grenades, most Tactical Space Marines carry a Bolter. This formidable anti-infantry firepower is complemented by a heavy weapon, such as a Missile Launcher, Lascannon or Heavy Bolter, and a special issue weapon, such as a Flamer or Meltagun. As these armaments are chosen to match the requirements of each deployment, and weaponry duties are rotated between all members of the squad save the sergeant, so all Tactical Space Marines must be trained and capable with every weapon their squad can be called upon to field. 
Of all Space Marine combat units it is the Tactical Squad that makes the greatest use of the Chapter's armour pool, often performing surgical strikes or seizing strategic points with the aid of fast-moving Razorbacks or Rhinos. Some Chapters - most notably the Angels of Fury, the Raven Guard and the Legion of Night - have even forged their combat doctrines around such tactics. Each Tactical Squad is led by a grizzled Sergeant who has survived and thrived through several decades, or even centuries, of hard and brutal campaigning. It is essential that a Tactical Squad be led by a canny and daring individual capable of reading the battle for opportunity, and it is quite common for Tactical Squad Sergeants to be seconded from the elite 1st Company of Veterans. This ensures that the core of a Chapter's combat forces have highly experienced leadership.
==== Scout Squad ====
When first accepted into a Space Marine Chapter after undergoing years of biological enhancement, an Initiate joins the ranks of the 10th Company as a Space Marine Scout. He is placed under the tutelage of a Veteran sergeant who will lead him into his first combats and oversee his training and educate him in what it truly means to be Astartes. A Space Marine Scout has much to learn. Not only must he become accustomed to the many genetically-engineered enhancements which are at work on his body, but he must learn the litany of battle which will fortify and strengthen him. Through a grueling training regime that lasts for many months, the Initiate will learn how to use the battlegear on which his life depends, and he will get his first real chance to fight the enemies of Mankind. Throughout his entire tenure as a Space Marine Scout, the Initiate is watched over and taught by his sergeant, his actions guided and judged as he strikes the foe at the weakest point with Bolter, shotgun and blade. As his training progresses, the Scout will grow proficient with many other Astartes weapons, such as the Heavy Bolter, sniper rifle, Missile Launcher and Meltabomb. Acting as part of an infiltration force, a Scout will become skilled at every aspect of war. He will learn that to be a Space Marine is to be death incarnate, no matter the terrain, the nature of the foe, or the weapons that dominate the battlefield. More lightly armed and armoured than more experienced Battle-Brothers, Space Marine Scouts chiefly fight as skirmishers. Their duties are to infiltrate enemy positions ahead of the rest of their Chapter, relying on stealth - rather than brute force - to accomplish their mission objectives. Operating behind enemy lines, Scouts set ambushes for the unwary, destroy ammunition dumps and vehicle pools, spy out the enemy's movements and gather what information they can about their opponent's plans. Sometimes Scouts will pounce unseen within an unsuspecting enemy camp, capturing a commander for interrogation or sabotaging equipment and supplies. Striking in silence, the Scouts' goal is to accomplish their mission and vanish before the enemy has the chance to retaliate in force. 
Scout squads are often detailed to conduct boarding actions against Tyranid Hive Ships or perform seek-and-destroy missions against the Hive Mind's synapse creatures that direct Tyranid invasions. As standard Heavy Bolter shells have often proven ineffective against the larger Tyranid bio-forms, most Chapters now issue their Scouts with specialised Hellfire ammunition -- heavy ceramic shells containing a virulent mutagenic acid that ruptures and burns its way through organic tissue. Such weaponry can bring down even a rampaging Carnifex, and is no less deadly when turned upon more mundane foes like Chaos Cultists. 
==== Crusader Squad ====
A Crusader Squad is the standard tactical organisation employed by the Black Templars Chapter of Space Marines. The Black Templars are organised in a different manner to many Codex Astartes-compliant Chapters and do not follow the dictates of the Codex Astartes in many ways, notably in the recruitment, training and deployment of their warriors. The majority of Black Templars Battle-Brothers -- known within the Chapter as Initiates -- are organised into Crusader Squads, which form the backbone of any strike force unleashed by the Chapter. Many Crusader Squads have the honour of being led to battle by one of the Chapter's Sword Brethren -- Veterans whose deeds and example inspire the Initiates to ever greater acts of courage. Crusader Squads are armed primarily with the holy Bolter, though given the Black Templars' preference for fighting their foes face-to-face, many choose to carry Chainswords and other weapons more suited to the cut and thrust of close combat, epitomising the Black Templars' righteous zeal and their drive to defeat their foes in battle. 
Before a Black Templars recruit marches to war as an Initiate, he must first prove his mettle as a Neophyte. Unlike other Space Marine Chapters, the Black Templars have no dedicated Scout Company in which its Aspirants are trained. Instead, the Black Templars' recruits train within a Chapter Keep and, once they are deemed ready by the Keep's Castellan, are transported to one of the Black Templars' fleets. Here, the Neophytes are put through even more gruelling trials as the Chapter's Initiates test their strength, martial skills and faith to the limits. Should a survivor of these trials impress one of the assembled Battle-Brothers, an Initiate may take it upon himself to personally mentor the Neophyte in the art of war. From that point on, the Initiate takes sole responsibility for his pupil's training and conduct. He swears an oath to prepare the Neophyte for his entry into the brotherhood that is the Chapter, teach him of its history, and guide him through its holy rites of worship to the Emperor. In return, the Neophyte pledges obedience to his master and vows never to bring dishonour to his name. Neophytes also act as servants to their mentors, waiting on them at the great banquets and seeing to their day-to-day requirements.
=== Fast Attack ===
==== Assault Squad ====
Assault Squads of Astartes excel at close-quarter, melee fighting. Equipped with Jump Packs and armed with Bolt Pistols and Chainswords, they scream across the battlefield like avenging angels, charging into the foe with little heed for danger. A Space Marine is commonly assigned to an Assault Squad after service amongst the Devastators. By this time he has garnered battle experience and can be counted on to hold his ground before the foe. Now he must temper himself in the most brutal arena of war and prove his worth in the melee of close combat. The Codex Astartes dictates that Assault Squads should be unleashed in the first wave of an attack, to strike hard and fast at weak points in the foe's formation. Opposing infantry are shredded with Chainsword and Bolt Pistol, enemy tanks with Krak Grenades and Meltabombs. Such is the way of the Space Marines - to deliver an irresistible and overwhelming blow to a single point, to crush the enemy without mercy before moving on to the next target. The Jump Pack is easily as dangerous as any weapon the Assault Marine carries. With a jump pack comes mobility, allowing the Assault Squad to traverse all manner of terrain swiftly and without hindrance, or even perform controlled low-altitude descents from Thunderhawk Gunships. So it is that the Assault Squad can be a weapon of subtlety in the hands of a capable commander. It can dive without warning on an enemy warlord who believes himself secure amongst his own lines, operate as a highly mobile counterpunch unit or perform vital reconnaissance in warzones unsuitable for the deployment of lightly-armoured, less-expereinced Scouts. In certain circumstances, Assault squads are even used as bait, luring an unwary enemy force onto a prepared defensive position, or redirecting them away to buy time for further preparation or evacuation. Often operating far ahead of the rest of the army, Assault Marines are in constant danger of being outflanked, cut off, or simply overwhelmed by the enemy. To guard against this, the commanding sergeant of an Assault Squad has a direct uplink to myriad datastreams and tactical overlays - the command and control relays through which the Space Marines coordinate their deployments and battles. Even if he is knee deep in corpses and fighting for his life, an Assault Squad sergeant must be aware not only of his current situation, but also any imminent developments that could leave his squad stranded in a sea of foes. Should this occur, only iron resolve will allow the Assault Marines to hack their way clear and claim victory. 
==== Land Speeder Squadron ====
The Land Speeders fielded by the Space Marines are an evolution of a Standard Template Construct (STC) pattern from the Dark Age of Technology discovered in the wake of the Horus Heresy advanced. Utilising this ancient technology, the Land Speeder uses a repulsion plate to skim a planet's gravitational field, simulating the effect of flight, and enabling it to perform low-altitude manoeuvres that more conventional atmosphere-capable craft would find nigh-impossible. Early Land Speeder designs were relatively unarmoured, but over the millennia the design has been modified with light adamantium plating. This alteration was made not for the sake of the crew - Power Armour provides a greater degree of protection than even the heaviest armour on a Land Speeder - but to better protect the vehicle's delicate control units. All of a Chapter's Space Marines are trained to fight as Land Speeder Squadrons as part of their service in an Assault Squad, but the craft are most commonly piloted by those Battle-Brothers who embrace the speed of which a Land Speeder is capable. With their versatile weapons loadout, Land Speeders can be tasked to a variety of battlefield objectives. These can range from lightly armed reconnaissance and Scout deployments, to tank hunting or other seek and destroy missions. The gravitational drive of a Land Speeder does not allow it to function at high-altitudes, but it can be used to perform a controlled descent from the upper atmosphere. This allows a Land Speeder to deploy from overflying Thunderhawk Gunships and assail the enemy without warning. Though they are often ordered to support other units, Land Speeders can be (and are) deployed en masse in many engagements. Some Space Marine Chapters routinely field their entire fleet of Land Speeders as a fast-moving and nigh unstoppable assault wave, blasting a hole in the enemy battleline that Rhino-mounted Tactical Squads can exploit, before peeling off and engaging another target with a similarly devastating effect. 
The Land Speeder's other variant patterns in use by many Astartes Chapters include: 
* The Land Speeder Tornado: The Tornado-pattern Land Speeder mounts twice as many heavy weapons as the basic Land Speeder and can also choose from a wider variety of weapons, able to mount an assault cannon or a heavy flamer. 
* The Land Speeder Typhoon: The Land Speeder Typhoon is extraordinarily effective at anti-personnel actions on the battlefield. The Typhoon mounts a twin-linked Typhoon Missile Launcher. The Typhoon Missile inflicts a hard hit at long range and rarely misses since it is twin-linked. The Typhoon Land Speeder variant's only real drawback is its lack of versatility - the Typhoon Missile Launcher is excellent at destroying infantry or light vehicles, but almost useless against even medium armour such as the Eldar Falcon or Tau Devilfish. 
* The Land Speeder Tempest: Sporting better armour, an assault cannon, and a twin-linked missile launcher, the Tempest is among the most feared versions of the Land Speeder. The Tempest has a difficult combination of weapons - the assault cannon has a medium range while the missile launcher fires out to a decently long range in comparison. Better frontal armour means that the Tempest can usually get in close to enemy troops without much worry. A maximum of only three Tempests are normally fielded in a standard Space Marine force. However, the twin-linked firepower of the Tempest's missile launcher and its heavier armour than the standard Land Speeder make the Tempest a force to be reckoned with. 
* The Land Speeder Storm: The Land Speeder Storm is a significant modification of the original design, trading the traditional heavy armament for a modest transport capacity. The resulting craft is the equal of its parent in matters of speed and manoeuvrability, but can also carry a small Scout Squad without any loss of performance. Furthermore, a Land Speeder Storm's baffled engines and sophisticated spy array afford it a stealthy profile best suited to the Space Marine Scouts' mission of clandestine hit-and-run attacks. As a result, each can be used as a mobile firebase, assault transport or stealth insertion craft as the combat objectives dictate. To further enhance the Land Speeder Storm's effectiveness in strike missions, many Chapters replace a Land Speeder's standard underslung Heavy Bolter armament with a Cerberus Launcher. This tri-barrelled weapon fires a disorienting volley of frag, stun and blind rockets into enemy positions, allowing the Scouts to move in and mop up any survivors. When combined with the rapier speed of the Land Speeder Storm, the Cerberus Launcher allows Scouts to launch rapid and daring assaults at an otherwise impenetrable defence line with impunity.
==== Space Marine Bike Squad ====
Astartes Bike Squads carry out fast-moving assault missions using 8 one-man Assault Bikes and sometimes with the addition of a single two-man Attack Bike, often operating on intelligence gathered by infiltrating Scout Squads or Land Speeder reconnaissance flights. A Bike Squad at full strength, for a total of eight bikes and one Attack Bike, can split into two combat squads. If this is done, one combat squad consists of five bikes and the other of three bikes and an Attack Bike. Bike Squads attack at incredible speeds, using surprise and unstoppable momentum to punch holes in the enemy formation, accelerating away as the enemy recovers his wits only to circle back and attack once again from an unexpected direction. For a Space Marine biker to operate at full potency, the superhuman rider and his mechanical steed must function flawlessly as one. To this end, the Codex Astartes dictates that all of a Chapter's Assault Marines, Scouts and the entire 6th Company should master the art of mounted warfare as part of their training regimen. A few Chapters take this further, with every Space Marine required to maintain his mounted training, even though he may have long passed into the 1st Company, or perhaps even into the exalted ranks of the Chapter Council. Few Chapters exemplify this better than the White Scars, who proudly employ Bike Squads as the main body of any strike force. Other Chapters are less enamoured of a Bike Squad's tactical value, preferring to send assault forces into battle in Rhinos or Razorbacks. The Space Marine bike itself is a robust construction. It needs to be, for it must be powerful enough to propel a fully armoured Space Marine at dizzying speeds, and yet responsive enough to perform a full range of death-defying combat manoeuvres. Even at low speeds the combined impact mass of bike and rider is no small thing to encounter. Indeed, many experienced Space Marine bikers can boast of riding through rockcrete walls at full pelt, suffering neither harm nor impediment. For the heaviest assault missions it is common for a Bike Squad's Assault Bike firepower to be further augmented through the attachment of an Attack Bike. Each Attack Bike is a highly formidable mobile firebase, with the twin Bolters of the bike itself augmented by a Multi-melta or Heavy Bolter mounted on a sturdy sidecar. So potent is the striking power of the Attack Bike that many Chapters field them in entire squads, employing them as fast-moving fire-support units to complement Scouts, Assault Marines or other bike squads. On those rare occasions when Attack Bikes are deployed en masse, as they were by the fabled White Scars Chapter during the Third War for Armageddon, they prove to be a nigh-unstoppable foe. 
During the final stages of a Space Marine Scout's training, he is attached to a Scout Bike Squadron. Scout Bikers are employed as fast-moving reconnaissance and disruption units. They operate on a far longer leash than other Scouts, often operating as a separate and distinct adjunct to the main Space Marine strike force, answerable to none save the commanding Sergeants of their Squadron. While Scout Bikers continue to perform the hit-and-run tactics they perfected in their earlier years of service, their repertoire of combat skills is broadened by hard-won experience and further augmented by supplies of special issue equipment. While the enemy concentrates on the main Space Marine attack, the Scout Bikers ride rampant behind his lines, calling down orbital bombardments and reserve deployments with pinpoint accuracy. 
==== Stormtalon Gunship ====
The Stormtalon gunship is an aerial interceptor and ground-attack aircraft that serves in the armies of the Adeptus Astartes. The Stormtalon possesses Vertical Takeoff and Landing (VTOL) capabilities which allows it to hover in place while unleashing its potent barrage as well as engaging in more conventional dogfights like a supersonic interceptor. The Stormtalon is swift enough to engage nearly all but the fastest of enemy aircraft whilst simultaneously being well-armed enough to reduce the chosen foe to a mangle of twisted wreckage and ruined flesh. The arrival of a single Stormtalon from the war-torn skies has reversed the tide of many desperate battles where the Space Marines on the ground faced certain defeat. The Stormtalon can always be counted upon to deliver a hail of ferocious firepower. Whether its weapons are pointed at enemy ground positions or incoming aerial opponents, it is more than capable of obliterating the threat. The Stormtalon gunship usually operates in a squadron of three, known as a Skyhammer Squadron. 
A Stormtalon is often assigned to escort other mission-critical units. In this role, the Stormtalon is all but unmatched. At one moment it can be screaming across the battlefield at death-defying speeds, at the next, its pilot can switch over to repulsor systems, trading raw speed for agility, all the while strafing enemy positions with a thunderous barrage of shells and missiles. Such were the tactics employed by the Ultramarines Chapter at the Battle of Cold Steel Ridge. Here, Stormtalon pilots pushed their gunships to the limit, afterburners propelling the aircraft to bone-jarring speeds in their attempts to intercept monstrous Harpies and flocks of Gargoyles whose winged bodies were darkening the skies. No sooner had the Stormtalons regained air-superiority than the pilots were vectoring their aircraft's engines, hovering above their Battle-Brothers on the ground and holding great swarms of charging Tyranids at bay with withering salvos of firepower.
=== Heavy-Support ===
==== Devastator Squad ====
Devastators are the most heavily armed of all Space Marine squads, trained to assail the enemy from great distance and with overwhelming firepower. As primarily long-range support troops, Devastators are capable of providing the Chapter's Tactical and Assault Squads with covering fire or engaging enemy vehicles and other heavily armoured targets. Unlike most other Space Marine squads, Devastators operate from a largely static footing, abandoning fixed positions only to advance, fall back or occupy a position with more commanding arcs of fire. This is not to say that Devastators cannot be flexible upon the field of battle, indeed, each squad has its own assigned Rhino transport for such redeployments. However, it remains true that Devastator Squads most completely define a Space Marine task force's reach and depth, for they promise destruction with greater range and measure than any of their Battle-Brothers. Most Devastator Squads are composed of Space Marines who have recently completed their tours of service in the Chapter's Scout Squads. 
Though they will have taken part in dozens -- or perhaps even hundreds -- of deployments as Neophyte Space Marines, service in a Devastator Squad will not only be their first experience of fighting in Power Armour, but also mark their first engagements as part of the main Astartes task force. When first promoted into a Devastator Squad, a Space Marine is issued with the Bolter and grenades with which he will grow ever more skilled throughout his service. His primary functions are to provide close-fire support, call out targets and generally act as backup for the more experienced Batttle-Brothers who carry the squad's heavy weapons. Only when the Neophyte has proved himself a steady and dependable warrior is he entrusted a heavy weapon from the Chapter's Armoury. Devastator Squads commonly carry four heavy weapons into battle. These can range from the Heavy Bolter and Missile Launcher, to the more exotic Multi-melta and Plasma Cannon. 
A single Devastator Squad is able to excel at several battlefield roles by the simple expedient of splitting into an anti-tank and an anti-infantry combat squad. Even so, a few Space Marines Chapters have refined the role of their Devastator Squads to suit a recurrent foe or engagement type. For example, the Crimson Fists, their tactics understandably skewed by near-annihilation at the hands of the Ork WAAAGH! Snagrod, tend to favour the hail of anti-personnel fire proffered by four Heavy Bolters. The Salamanders and Imperial Fists, however, deploy their Devastators with Multi-meltas and Lascannon to crack the formidable armour of enemy tanks and fortifications. 
==== Centurion Devastator Squad ====
A Centurion is a Space Marine who has been equipped with a powered exoskeleton worn over his normal suit of Power Armour known as a Centurion warsuit that allows him to serve a heavy ranged or close combat assault role between that of a normal Astartes and a Terminator. A Centurion warsuit enables a Space Marine to stride into battle with the firepower of a battle tank at his fingertips. Protected by thick ablative plates of ceramite, a Centurion warsuit renders its pilot immune to all but the most powerful of weapons. Named after the Space Marine Legion leaders of old, the Centurion warsuit design was unearthed in the aftermath of the Age of Apostasy in the 36th Millennium, and after sanction by the Adeptus Mechanicus, the suits found their way into the armouries of almost every Space Marine Chapter. 
Centurion Devastator Squads are long-range specialists who pound enemy positions with salvos of heavy weapons fire. A Centurion Devastator Squad's only real weakness is its lack of speed, for whilst they can outgun entire squads of enemy infantry, they are easily outpaced by the fast-moving elements of a foe's strike force. Thus, they are primarily employed to besiege defended enemy positions or to defend their own fortifications, or used as mobile firebases to strengthen advancing battle lines. Centurion Devastator Squads are led by a Centurion Sergeant. 
==== Predator ====
The Predator is a heavily-armoured Rhino variant that is used as a main battle tank by most Space Marine Chapters. With the added weapons it offers there is no space remaining for troop transport. The Predator sacrifices transport capacity for improved frontal armour and heavy turret-mounted armament. The result is a well-armed and mobile tank, equally capable of holding ground or spearheading armoured assaults into the most heavily defended of enemy territory. Armed with either an Autocannon or twin-linked Lascannons on its main turret, it can also have Heavy Bolters or Lascannons mounted on sponsons to either side as well. The Blood Angels Chapter has been known to field a "Baal" variant of the Predator. The Baal Predator is equipped with a twin-linked Assault Cannon on its main turret and a single Heavy Flamer or Heavy Bolter mounted to either side on sponsoons as well. 
The efficiency and durability of the Predator design are attested to by its long and proud history. Indeed, the records of the Adeptus Mechanicus indicate that the Predator was instrumental in establishing Mankind's dominance in the galaxy during the Dark Age of Technology. Here its formidable firepower and reinforced armour were decisive in curbing the menace posed by all manner of alien races, the savage Orks and mysterious Eldar foremost amongst them. It is small wonder that the Predator has become a byword for armoured might, and its unique appearance became as much a symbol of the Imperium of Man as the Aquila upon its adamantium hull. The Predator is a highly versatile vehicle, capable of receiving a number of weapon load-outs. There are two classes of Predator currently in use by the majority of Space Marine Chapters. 
The Destructor pattern is equipped with a turret-mounted Autocannon, perfect for the suppression of light vehicles or troop formations, whilst the twin-linked Lascannon of the Annihilator pattern is deadly to enemy armour. The firepower of both Predator types can be further augmented by sponson-mounted weapons as noted above. Most Chapters employ a variety of Predator patterns, although some heavily favour one model. Though a Space Marine Chapter will occasionally field its full fleet of 20 or so Predators as an armoured task force, the Predator's chief function is to provide fire support for the Chapter's infantry. In reinforcement of this designation, each freshly forged Predator is assigned a name that reflects its role as a protector of the Chapter's brethren. Indeed, a Predator's name may endure in the collective memory of a Chapter of Astartes long after its various crews are forgotten by all of a Chapter's histories. Heart of Defiance, Orar's Sentinel and Blade of Honour all hold revered positions in the battle sagas of the Ultramarines and their destruction is mourned as greatly as the passing of any of the Chapter's greatest heroes. 
==== Whirlwind ====
Intended to be used as an elite, highly mobile force, the Space Marines normally have little need for heavy artillery pieces. However, the Codex Astartes does recognise the need for devastating support fire, particularly when engaging numerous hordes or highly mobile foes. It is vital that such enemies are broken or suppressed from a distance before they can take advantage of the Space Marines' lack of numbers. However, when the use of heavy firepower is called for, the Astartes can utilize the Whirlwind, another variant of the Rhino chassis armed with a long-range missile pod, that can bombard enemy positions in preparation for an Astartes offensive. Whirlwinds use two types of ammunition in the form of Frag and Krak Missiles, the use of which is determined by the nature of the threat they will engage. As with the Predator, there is no room left inside these vehicles for troop transportation after they are outfitted with the new weapon configuration. It is for this specialised mission that the Whirlwind was designed. Thanks to its target acquisition system, the Whirlwind is able to bombard hidden or entrenched targets with incredible accuracy, often from behind the safety of cover. The Whirlwind's normal payload consists of solid fuel Frag Missiles, launched in programmed salvos of paired rockets. The Whirlwind's sophisticated telemetry ensures that each barrage is delivered for maximum effect, resulting in a more formidable blast than that provided by conventional Frag Missiles. The Whirlwind is also able to fire Castellan Incendiary Missiles. Here the fragmentation charge is exchanged for a volatile Promethium-laced chemical warhead that throws out a blanket of searing flame on detonation. Even the most entrenched bulwarks offer no protection against a sustained barrage of Castellan Missiles - if the defenders are not roasted alive by chemical fires, the acrid and acidic vapours swiftly eat them alive from the inside out. The combination of manoeuvrability and overwhelming firepower offered by an experienced Whirlwind crew is an asset much prized by all Space Marine commanders. Some Chapters enhance the Whirlwind's devastating psychological impact upon foes still further by altering the Whirlwinds' payload so that the missile emits a terrible screeching wail as it hurtles through the sky. Sometimes the sound alone is sufficient to drive the foe from their fortifications, allowing the Space Marines to advance unopposed. 
==== Vindicator ====
When attacking heavily fortified enemy positions, Space Marine Chapters use a Vindicator, another Rhino variant, which fills nearly the entire Rhino chassis with the massive, snub-nosed Demolisher Cannon that is capable of blasting through the thickest of walls. This weapon has proven so effective that the Iron Warriors Traitor Legion makes it a point to scavenge these Imperial machines for their own use whenever possible. The notion of fitting a high-calibre cannon into the hull of a Rhino first evolved during the very early years of the Horus Heresy, during the fierce inner-city battles on Rothern I. Traitor formations had transformed the labyrinth of alleyways and rockcrete structures into formidable defensive positions, and the Loyalist forces had to devise a way of delivering bunker-busting ordnance with precision amongst the cramped streets. Large-bore Thunderer Cannons were mounted onto remodelled and up-armoured Rhino chassis. Thus was born the Vindicator, undisputed victor of the Rothern I campaign, and evermore an essential part of any Space Marine Chapter's Armoury. In the millennia since the Heresy, the Vindicator has been called upon again and again to bring the Emperor's judgement to the foes of Mankind. Amid the snarl of a Hive World's streets or similar environments the Vindicator is unparalleled. Where other vehicles would quickly be outflanked, the Vindicator can simply obliterate obstacles that lie in its path and surge forwards over the broken rubble. However, there has been a steady stream of upgrades and technological tweaks to the vehicle pattern carried out by inventive Techmarines as time has passed. The most significant of these alterations has been the replacement of the bulky Thunderer Cannon with the much more compact, but no less potent, Demolisher Cannon. A legion of other alterations have been applied to armour plating, fire control and drive mechanisms. For larger engagements, a squadron of Vindicators flank the advance, unleashing their punishing firepower in support of the breaching Land Raiders. On smaller scales, a Vindicator may itself be the spearhead of the formation, punching a hole in the enemy fortification and allowing Space Marine and allied infantry to stream through in its wake. 
==== Hunter ====
The Hunter, also known as the Whirlwind Hunter, is a variant of the standard Space Marine Whirlwind Artillery Tank and serves as the Space Marines' primary surface-to-air combat unit. Armed with a potent Skyspear Missile Launcher, the Hunter has proven its worth in countless war zones, scouring the skies of enemy bombers and fighter craft. The Hunter is the primary surface-to-air combat vehicle of the Adeptus Astartes and is the first known dedicated anti-aircraft platform fielded by the Astartes. Prior to the discovery of the Standard Template Construct (STC) data for the Hunter, many Space Marine Chapters had attempted to retrofit the Whirlwind in various ways, with mostly negative results. The vehicle is based on STC data which is much older than the much more recent Whirlwind Hyperios anti-air tank. Though the Whirlwind Hyperios is a stable pattern of anti-air combat vehicle and is becoming widely adopted by many Chapters, there are still many Chapters that have continued to use the Hunter on the battlefield, including during the recent Third War for Armageddon, where the Hunter was used in great numbers by Astartes Chapters like the Black Templars who participated in that conflict. The Hunter also features improved front and side armour over the standard Whirlwind, and is outfitted with hydraulic stabilisers that anchor the vehicle to the ground so that when it fires its anti-aircraft artillery it suffers no recoil. 
==== Stalker ====
The Stalker, also known as the Whirlwind Stalker, is a specialised, mobile anti-air platform and variant of the Whirlwind Hunter, itself a variant of the Whirlwind Artillery Tank. The Stalker is an adaptation of the Hunter Standard Template Construct (STC) that was unearthed by the Adeptus Mechanicus only a few millennia ago. Mounting a pair of independently tracking Icarus Stormcannons, the Stalker can target multiple enemy contacts, stitching the skies with a hail of armour-piercing death. The Stalker is a relatively new addition to the armouries of the Adeptus Astartes, having only been put into production relatively recently since its STC data was rediscovered only several millennia ago. The Stalker is a vital part of a Space Marine Chapter's armoury and it is deployed as a rapid-firing anti-aircraft platform that is able to track and engage multiple enemy targets simultaneously. The Stalker's front and flank armour is thicker than most other Rhino-chassis-based vehicles, allowing the Stalker to deflect or absorb more incoming enemy fire. The Stalker's sides also feature hydraulic stabilisers that anchor the vehicle to the ground so that when it fires its anti-aircraft artillery it suffers no recoil and loss of accuracy. 
==== Land Raider ====
The Land Raider is one of the most powerful main battle tanks at the Imperium's disposal, and also one of the rarest in use by Imperial forces since only a few Imperial Forge Worlds still possess the secrets of its manufacture. A Space Marine Chapter is lucky if it has more than five at its disposal. The Land Raider can transport troops into battle, carries enough weapons to blast its way though nearly any defense, and has armour plating thick enough to withstand massive amounts of firepower. The normal Land Raider pattern is called the Phobos. It carries a hull-mounted, twin-linked Heavy Bolter able to turn light infantry into sludge. It also carries 2 twin-linked "Godhammer" pattern Lascannons in its two side sponsons, making the Land Raider an extremely formidable foe for armoured vehicles, able to stand up for itself in any fight against another vehicle, and come out victorious almost all of the time. Land Raiders are also equipped with a "Machine Spirit", an Artificial Intelligence crafted by the Adeptus Mechanicus. The Machine Spirit is smart enough to move the tank and fight even without a crew. It enables the tank to move even when the crew has been stunned, and is able to operate one weapon of the player's choice, to shoot at a target. However, the artificial intelligence of the machine spirit is nothing compared to the battle-hardened Space Marine crew of the Land Raider, and as a result, accuracy suffers considerably. 
With transport capacity for a full squad of Space Marines, their field supplies, communications gear, munitions and medical facilities, the Land Raider is well suited for striking deep behind enemy lines and surviving for long periods in the field. This flexibility is further reinforced by a sealed hull and the complex environmental systems that allow it to operate in practically any theatre of battle. Indeed, the Land Raider is as fearsome in the airless atmospheres of dead moons as it is in the fume-choked environs of a Hive World. The Land Raider can also function without ill-effect under the extreme pressures of submarine environments, using its powerful tracks to traverse sea- and riverbeds and assail the foes from an unexpected angle. A Land Raider is a blessed artefact to the Techmarines that oversee its repair and maintenance. This is not least because a Land Raider's Machine Spirit is so much stronger than that of lesser tanks, a fact taken to mean that a substantial portion of the Machine God's essence resides within the Land Raider's impenetrable adamantium hull. Accordingly, should even a Land Raider's sponson be lost in battle, the rest of the Chapter will fight like men possessed for its retrieval, often calling in further reinforcements to ensure that the component is not lost. So it is that lives of men can be stilled in order to preserve the spirit of a machine, but the Space Marines honour such a sacrifice and go willingly into a battle of this kind. 
Land Raiders were once used by all the branches of the Imperium's armed forces at the time of the Great  Crusade. During the Horus Heresy, the Emperor of Mankind ordered that their use be restricted to the Space Marines, as they were the Imperial forces at the forefront of that terrible civil war. The popularity of this mighty war engine was so great, that an entire Forge World, Anvilus 9, was entirely converted solely to Land Raider production. But, at the beginning of the Horus Heresy, Anvilus 9 was overrun by Chaos-corrupted Tech-priests from the Dark Mechanicus. Other Forge Worlds of the Imperium also ceased to function, either suffering the same fate as Anvilus 9 after being captured by the Forces of Chaos, or chose to become neutral in the struggle to see which side emerged triumphant, leaving only a small number of Loyalist Forge Worlds still producing goods for the glory of the Emperor. As a result, Land Raider production suddenly slowed to a trickle. With Horus' forces threatening to overrun Terra, the heart of the Imperium, the Emperor decreed that all Land Raiders still on the Loyalist side were to be for the exclusive use of the Space Marines, who were always at the forefront of the Imperium's cause. Once the Horus Heresy had been crushed following the sacrifice of the Emperor, the decree of exclusive use of the Land Raiders by the Adeptus Astartes remained in place, as none dared to revoke the Master of Mankind's most holy commandments. Thus, the decree has remained in place for the last ten thousand years. 
==== Land Raider Crusader ====
The Land Raider Crusader is nearly identical to the standard Land Raider pattern, but is armed to provide short-ranged, anti-infantry support. A linebreaker without peer, the Crusader can smash through enemy formations and fortifications alike, disgorging Space Marine assault troops into the heart of the enemy position. Numerous short-ranged and swift-firing weapons allow the Crusader to weaken the enemy before the assault is launched, and provide a torrent of fire to support its cargo once in combat. Most crews use their vehicles as adamantium battering rams, relying on the Land Raider's mass to crash through walls, shoulder aside tanks and pulverise enemy troops. The Land Raider Crusader is armed with a hull-mounted twin-linked Assault Cannon turret, and sponson-mounted Hurricane Bolters (essentially six standard Bolters fire-linked together). It is also equipped with a Multi-melta to burn through armoured walls, and its front is studded with Frag Grenade Launchers to assist the troops disembarking from its front ramp. The removal of the Lascannons and their Plasma Generators allows for greater troop capacity. The Crusader may transport 8 Space Marines in Terminator Armor, or 15 Astartes in standard Mark VII Power Armour. The Crusader variant of the Land Raider was developed by the Black Templars Chapter during the Jerulas Crusade. The fortifications upon which the Jerullian Hive Cities were founded, though ancient, were nonetheless a formidable obstacle to the Black Templars' wrath. Before such a weapon even the fortresses of Jerulas could not stand, and soon the Black Templars were victorious and the Land Raider Crusader hailed an unmistakable success. As news of the Crusaders' success spread, other Space Marine Chapters requested information regarding their remodelling of the Land Raider. In 763.M39, due in no small part to the favourable stance taken by the Ultramarines, the Crusader pattern was sanctioned by the Adeptus Mechanicus. In truth, many Chapters had been utilising the Crusader for some years already, but the blessing of Mars ensured the design's survival. With the support of the Forge Worlds, the Crusader began appearing ever more frequently on the battlezones of the Imperium and has since become the mainstay of many a Chapters' combat strategy. 
==== Land Raider Redeemer ====
The Land Raider Redeemer is an evolution of the Land Raider Crusader variant, created by the Fire Lords Chapter. As the Crusader was a modification of the original Land Raider, so is the Redeemer an evolution of the Crusader pattern. The Redeemer retains the Assault Cannon and Frag Grenade Launchers of the Crusader, but eschews the Hurricane Bolter sponsons for colossal Flame Projectors that send a billowing tide of burning Promethium into the thick of the foe. Combined with the Redeemer's sophisticated targeting systems, these so-called Flamestorm Cannons are able to purge even a well-defended bunker complex in seconds. An assault fought amongst the rubble-strewn and treacherous environs of a ruined city is the most gruelling kind of battle. Combatants lurk in the maze of ruined buildings, taking shelter amongst tumbled rockcrete and using a thousand vantage points to snipe at the enemy. For the Space Marines, whose whole combat doctrine revolves around the concept of a swift war won before the defender realises that he is fighting, such a situation is intolerable - the foe must be driven from his stronghold, and swiftly. In such battles, only fire will purge the enemy from his nest. Captain Jaric Phoros of the Fire Lords, tasked with restoring the Emperor's law to the civil war-plagued world of Grissen, Phoros directed his Techmarines to construct a weapon that would win the war. Within a week of the first Land Raider modifications the Fire Lords took Grissen's capital city. Within a month, the largest planetary faction was suing for peace and Grissen was part of the Imperium once more. In the wake of the Grissen campaign, Phoros disseminated his new design's schematics. Having always been possessed of a sardonic frame of mind, he named the new pattern Prometheus after an ancient god from Terran legend who brought fire to men. He changed the official designation to Redeemer only upon learning that the name was already taken by a Land Raider variant developed by the Salamanders. Nonetheless, the original Redeemer still serves in the Fire Lords' 2nd Company, the name Prometheus resplendent on its flanks and honoured in the Chapter's histories. 
==== Thunderfire Cannon ====
Space Marine task forces are intended to carry out swift, lightning-quick assaults, and a unit in an Astartes force that cannot maintain a rapid advance swiftly becomes a major liability. For this reason, most Space Marine fire support artillery units are mounted on armoured vehicle chassis that can keep pace with the rest of the army, as can be seen in the cases of the Vindicator and the Whirlwind. Designed for the static defence of a fortified Space Marine position, the Thunderfire Cannon is the one exception to the Space Marines' emphasis on mobility. Mounted on slow-moving but rugged tracks, each Thunderfire Cannon is a quad-barrelled minigun capable of maintaining a withering hail of fire. The Techmarine manning a Thunderfire Cannon can set its shells to detonate in a variety of different ways, depending on the tactical situation. Surface detonations are employed against numerous enemies in comparatively clear terrain, whilst airburst shells are used to scour a foe from cover. The most devastating barrage, however, is one programmed to burrow deep into the ground before detonating. Though the force of the blast is greatly reduced, the resulting shockwave is often sufficient to knock enemies sprawling, making them easy prey for other Astartes' weaponry. Thunderfire Cannons are primarily employed in mountainous or broken planetary terrain, where the more traditional Space Marine mobile artillery units, such as Whirlwinds, cannot operate. Though a Thunderfire Cannon is capable of moving on its own, they are normally deployed from Thunderhawk gunships or other fast-moving transport craft from a Space Marine force's orbiting Strike Cruiser or Battle Barge. Thunderfire Cannons are also invaluable in defensive deployments and evacuation missions, where their high rate of anti-personnel fire and disruptive subterranean shockwaves can wreak a glorious wrath amongst the attacking forces. 
==== Stormraven Gunship ====
The Stormraven gunship is a highly versatile multi-role aircraft found in the armoury of the Adeptus Astartes. The Stormraven can act simultaneously as an armoured transport, orbital dropship, and strike aircraft. This aircraft is smaller than the larger and more common Thunderhawk gunship that has been used by the Adeptus Astartes since the Great Crusade, and thanks to its array of vectored thrusters the Stormraven is also much more agile while in flight. The Stromraven's impressive speed and maneuverability, when used in conjunction with the superhumanly precise skills and reaction times of its Space Marine crew, allows the aircraft to effortlessly evade enemy interceptor fire and manoeuvre at full thrust through the cluttered spires of a hive city or through the mega-fauna of a jungle-covered Death World. The Stormraven is capable of carrying up to twelve Power Armoured Space Marines in its armoured troop hold, and is even capable of carrying up to six Assault Marines, although their Jump Packs take up half of the interior room. The aircraft can also transport an Astartes Dreadnought by way of external grapples. Many times if a Stormraven is destroyed while in-transit, the Dreadnought is capable of surviving and later being recovered by the Chapter's Techmarines. It is currently unknown if the Stormraven is capable of transporting Terminators. 
The Stormraven Gunship is a relatively recent introduction to the armouries of the Adeptus Astartes. Indeed, as befits a bureaucracy as labyrinthine and cliquish as that of the Imperium of Man, there are no official records to explain the vehicle's emergence. Certainly, the Stormraven began service and proved its worth within the Grey Knights and Blood Angels Chapters, and some records suggest that it was not meant to see broader use until the Adeptus Mechanicus were fully satisfied with its performance. However, in such dire times as the late 41st Millennium, when the fate of humanity itself rests on a knife's edge, the Adeptus Astartes need every weapon they can find; sanctioned or not, and many Space Marine Chapters now field a handful of the aircraft alongside their more traditional strike vehicles. 
The role of a Space Marine strike force's Stormraven Gunships varies greatly from battle zone to battle zone and, to an extent, in response to the personality of the strike force's commander. Whilst most Space Marine Chapters utilise their Stormravens in concert with their other transport vehicles, there are a handful who have come to use them as the primary means of deploying Battle-Brothers to an objective, combining, as they do, the swift orbital descent of the Drop Pod with the battlefield versatility of a Rhino or Razorback. Twelve Power-Armoured Space Marines can be accommodated within the Stormraven's adamantium belly, ready to charge out of the gunship once the assault ramp clangs down, or to make an aerial descent via Grav-Chutes should a landing not be possible. 
Furthermore, the Stormraven can also carry a mighty Dreadnought in its rear cargo grapples -- it is the smallest Space Marine aircraft able to do so. Yet to use the Stormraven as a transport alone is to overlook its formidable array of weapons. Whilst the precise load-out varies greatly from gunship to gunship, the Stormraven's firepower is easily the equal of a Chapter's most potent land-based fighting vehicles, and more than capable of wreaking untold destruction upon a deserving foe.
=== Dedicated Transport ===
==== Rhino ====
A fast troop transport, a Rhino APC (Armoured Personnel Carrier) can hold up to 10 Space Marines, a full squad, not including the two Astartes crew members who drive and operate it. The chassis of the Rhino is very versatile, and serves as the basis for many of the other Space Marine armoured vehicles. The Rhino can be outfitted with pintle-mounted weapons. Rhino armoured troop carriers are the mainstay of every Space Marine Chapter's vehicle pool. With an optimal balance of armour, transport capacity and manoeuvrability, the Rhino allows the Space Marines to swiftly redeploy, rush squads into positions of strategic advantage or conduct surgical strikes on the enemy lines. As with much of the technology employed by the Imperium, the Standard Template Construct (STC) design for the Rhino dates back to the earliest days of human interstellar colonisation during the Dark Age of Technology. It has changed little in the intervening millennia, for one of the Rhino design's great triumphs is its ease of assembly and simple adaptation to alternate construction methods and fuel systems. In the past, much of the Imperium's war machine relied on the Rhino, but now the knowledge of its construction and maintenance has largely faded as Mankind has continued to stagnate and even move backwards technologically in many ways. Only the Space Marines and a handful of other Imperial organisations can boast Rhinos in numbers sufficient to meet their needs. The core triumph of the Rhino's design is its durability and ease of repair. Indeed, most Rhinos contain rudimentary self-repair systems that can restore their drive systems even after damage so severe that many similar vehicles would be permanently inoperable. However, such damage is rare, for the Rhino's design is incredibly rugged. Given time and the necessary facilities, a skilled Techmarine can nurse even a badly battered wreck to life, reconsecrating it in the eyes of the Machine God and restoring it to the Chapter's service. As a result, many Rhinos have remained in service for thousands of standard years. Over that time almost every component and armour plate will have been replaced or been subject to significant repair, but the honoured name and designation of the Rhino lives on. 
==== Razorback ====
A Razorback is a variant of the Rhino chassis that sacrifices some troop carrying capacity for additional firepower. Razorbacks are commonly mounted with twin-linked Heavy Bolters or twin-linked Lascannons on a single turret on the chassis, and are excellent for providing fire support to smaller squads. They can, however, also utilise Assault Cannons, or Multi-meltas. With the addition of the turret, the Razorback's troop capacity is limited to 6 Space Marines. The vast Armouries of the Space Marines contain many types of fighting vehicles. Some have been used for thousands of years whilst others, like the Razorback, have only recently been rediscovered. Standard battle doctrine dictates that Razorbacks should be deployed as fire support vehicles, accompanying Rhinos or infantry squads into the thick of battle. As Rhinos have little in the way of firepower, even a single Razorback assigned as escort can greatly increase the effectiveness of an assault. Impressed by its versatility, several Chapters have begun to field the Razorback in other roles, employing them as mobile command centres and heavy reconnaissance screens. Despite the Razorback's proven effectiveness, some of the more conservative Space Marine Chapters regard it with distrust, claiming that it is "new" technology and still not sufficiently proven in battle. While this has a certain inherent logic - the Razorback has been in use for a mere four thousand years, whilst the Rhino and Predator predate the Horus Heresy - the fact that most Chapters have embraced the Razorback as a keystone of their operational doctrines serves to highlight this suspicious attitude as misguided. Some time in the future the Razorback may replace the Rhino as the mainstay transport of the Space Marines. 
==== Thunderhawk Gunship ====
The Thunderhawk gunship is one of the Space Marines' primary weapons in the war against the enemies of the Imperium. The Thunderhawk was first deployed during the Great Crusade after its discovery as a Standard Template Construct (STC) design by the Emperor of Mankind, to replace the Warhawk VI gunship, better known as the Stormbird. Armed to the teeth with a Thunderhawk cannon and various other weapons, its use became more and more widespread over the millennia. Each Chapter of the Adeptus Astartes maintains its own Thunderhawks. Normally reserved for large-scale battles, time and time again its use in the various fields of war has been proven to be of inestimable value. The use of a flight of Thunderhawks to provide supporting fire and the rapid deployment of a detachment of Space Marines or Imperial Guardsmen to a critical battlefield location is a favourite of Imperial Commanders. Thunderhawk variants can also be used as transports for the Space Marines' various armoured vehicles, aerial ground support and anti-armour gunships or even as fighter craft to destroy enemy air superiority fighters when necessary. 
With hardened Ceramite armour, a substantial transport capacity and a devastating weapons array, Thunderhawks are versatile craft indeed. Although initially designed to airlift Space Marines into a battlezone and then provide fire support, the Thunderhawk's role has broadened considerably over the millennia, with many Chapters using them as highatmosphere reconnaissance craft, long range strike assets or even spacebound heavy fighters. In the hands of an experienced commander, a single Thunderhawk Gunship can double the effectiveness of a Space Marine strike force, particularly in warzones where manoeuvrability is key to victory. 
==== Drop Pod ====
Drop Pods are atmospheric transports used primarily by Imperial Space Marines for orbital insertion and planetary assaults where achieving tactical surprise is often an important factor. The Drop Pods of the Adeptus Astartes look and work similarly to a starship's Life Pod and can carry either twelve Tactical Space Marines, a single Dreadnought or a single Thunderfire Cannon. They are launched from a vessel in low orbit towards the drop zone, usually in the midst of or near a battlefield. Once launched, they plummet through the atmosphere until their retro rockets fire to slow their descent. A computer Machine Spirit guides the Pod to its destination and can receive further commands from the Pod's mothership. Although the Pods become immobile after having landed on a planetary surface, they can be recovered by the Chapter's Techmarines and reused. 
==== Land Speeder Storm ====
The Land Speeder Storm is an uncommon variant of the standard Land Speeder used by the Adeptus Astartes. The Land Speeder Storm sacrifices the heavier weaponry of the more common Land Speeder variants, such as the Land Speeder Tornado and Land Speeder Typhoon, in exchange for a modest transport capacity. The Land Speeder Storm is capable of carrying a small squad of Scout Marines into battle without any loss of performance. The Land Speeder Storm is mainly used as a fast reconnaissance vehicle, and is capable of deploying Scout Marines deep into enemy territory without being noticed. The Land Speeder Storm is also equipped with baffled engines, which severely reduces their noise output, and a sophisticated spy array that helps gives the Land Speeder Storm an advantage during hit-and-run attacks. When the vehicle's cargo of Scout Marines are in the field, the vehicle can act as a mobile firebase to provide support, or the vehicle can act as an assault craft and drop the Scouts into hotly contested areas. The Land Speeder Storm is most commonly used as a stealth insertion craft, deploying the Scouts deep behind enemy lines where they can harass supply lines and destroy important targets.
== Chapter Fleet ==
All Space Marine Chapters maintain a fleet of starships and other spacecraft, which by the dictates of the Codex Astartes and the limitations placed upon the Astartes by the High Lords of Terra during the Reformation of the Imperium after the Horus Heresy, is supposed to be focused on intra-system transports and planetary assault. By tradition, only the Space Marines' smaller spacecraft are purposely designed to serve as gunships that are optimised for naval warfare and fleet actions. There are some Chapters that that have always railed against these restrictions, especially those that spend all of their time on Crusade or who possess no homeworld or fortress-monastery save for their fleet. These Chapters usually ignore these ancient restrictions and as a result often come into political conflict with the Imperial Navy, which fears seeing its monopoly on ship-to-ship combat eroded by the far more capable fleets of the Adeptus Astartes. 
Rather than making use of very tightly-defined classes of starships like the Imperial Navy, most Chapters define their spacecraft by a far broader classification system that is defined by utility, with some of the few exceptions like the Imperial Fists' Phalanx being themselves ancient relics of the Great Crusade or unique human-built warships left over from the Dark Age of Technology or captured as prizes from other species and converted to the Chapter's use. The Battle Barge is the largest and most powerful Space Marine starship ever constructed by the Imperium of Man, and few but the most potent Chapters possess more than 2 or 3 of these extraordinarily powerful warships. Battle Barges are equivalent in size and firepower to Imperial Navy Battleships and were designed first and foremost for survivability under the heaviest forms of enemy fire--a necessary trait when spearheading a planetary invasion, the Astartes' most common form of military operation requiring such a vessel. Battle Barge designs back up this incredible durability with massive if usually short-range firepower to aid the Astartes in their assault operations, along with a substantial number of launch bays for Thunderhawks, other Attack Craft and Drop Pods. Because of the incredible durability of their armour and Void Shielding, as well as their massive arsenals of the Imperium's most powerful weapons, few known starships, save for full-scale Battleships, can stand up to a Battle Barge in close-action space combat. Thanks to the Space Marines aboard one, a Battle Barge is an even more terrifying opponent during a ship-to-ship boarding operation. In addition to the Battle Barge, the Strike Cruiser is the most common type of heavy warship in Space Marine Chapter fleets. Strike Cruisers are high-speed rapid response cruisers, intended for use in planetary assault and pacification operations. Strike Cruisers are able to carry a company-sized strike force of Astartes to a combat zone and deploy them with preternatural rapidity. The last common type of starship found in Space Marine fleets are rapid strike vessels. These warships are small, Warp-capable Escorts that include Attack Craft, Frigates and Destroyers which serve as both line-of-battle Escorts for capital ships and system patrol vessels as well as infiltration ships that can be used to deploy small groups of elite Astartes behind enemy lines for reconnaissance in force or hit-and-run raiding missions. 
In addition to these more common types of Space Marine warships, fleet-based Chapters often make use of a number of other support vessels such as scout-surveyors, Adeptus Mechanicus Forge Ships and the massive, mobile fortress-monasteries known as Chapter Barques (often created from converted mass-conveyors normally used by Imperial merchants for the mass hauling of cargo between star systems). Chapter Barques allow a fleet-based Chapter to avoid risking their precious stores of gene-seed and other irreplaceable artefacts and relics on the frontline of battle or Crusade. Fleet-based Chapters also make use of vessels called Vanguard Cruisers that are refitted Strike Cruisers intended to undertake long-range, long-duration operations independent of support from the rest of the Chapter, often serving as reconnaissance or exploratory vessels for the Chapter fleet or as Heavy Escorts. Vanguard Cruisers are less capable of undertaking planetary assaults like normal Strike Cruisers because their weapons profile has been optimised for ship-to-ship combat, planetary exploration, reconnaissance and boarding operations.
== Space Marine Chapters ==
=== First Founding ===
The Space Marines were originally divided into 20 large Legions created during the First Founding by the Emperor, and each Legion was filled with thousands of Space Marines whose gene-seed was based on genetic material drawn from one of the original Primarchs. When 18 of the 20 original Primarchs were rediscovered during the Great Crusade, they became the leaders of the Legion genetically related to them. During the Horus Heresy half of the Legions turned Traitor to the Imperium and swore themselves to the Ruinous Powers of Chaos becoming the 9 Traitor Legions of Chaos Space Marines. 
=== Loyalist Chapters ===
Those Astartes Legions that remained loyal to the Emperor during the Horus Heresy were known as the Loyalists. They were subsequently each split up into smaller Chapters of only 1,000 Space Marines each during the so-called Second Founding, one of which retained the name of the original Space Marine Legion.
Chapter Name 	Primarch 	Homeworld 	Comments
Dark Angels 	Lion El'Jonson 	Caliban (destroyed)	The Dark Angels refer to themselves and their Successor Chapters as the Unforgiven. Their first two companies are elite forces known as the Deathwing and the Ravenwing. Although unknown to most of the Imperium, including the majority of the Chapter, some of the Dark Angels turned to the service of Chaos during the Horus Heresy. These individuals are known as the Fallen Angels and the Dark Angels and the Unforgiven have vowed never to rest until all of the Fallen have repented or been killed in the Emperor's name.
Son's of White	Logan of the White	Lupas 	
White Scars 	Jaghatai Khan 	Mundus Planus 	The White Scars have a Mongol-based nomadic barbarian culture and prefer fast-attack operational doctrines. They are also known for being specialists in the use of bike squads on the battlefield, using them as mechanical steeds.
Space Wolves 	Leman Russ 	Fenris 	This particular Chapter is known for following its own path and being highly unorthodox in organization and tactics - often contrary to the Codex Astartes. They are feral in appearance and are often adorned with wolf pelts and wolf tooth necklaces. They are one of the few Space Marine Chapters who do not follow any of the rules for Chapter organization set out in the Codex.
Imperial Fists	Rogal Dorn 	Terra/ Phalanx 	This Chapter is renowned for being the greatest siege specialists in the Imperium of Man. They also are engaged in a bitter and ancient feud with the corrupted Chaos Space Marines of the Iron Warrior Traitor Legion who were once considered the greatest creators of static defences in the galaxy.
Blood Angels 	Sanguinius 	Baal 	The Blood Angels suffer from the Black Rage and the Red Thirst, those that succumb to the Black Rage and the Red Thirst are put into the specially-created Death Company as the crazed Battle-Brother sees only the last moments of his Primarch Sanguinius' death at the hands of Horus and enters a killing frenzy during which he will literally drink the blood of his foes. The Blood Angels prefer the usage of jump packs and close combat.
Iron Hands 	Ferrus Manus 	Medusa 	The Iron Hands are devotees of the Cult of the Machine of the Adeptus Mechanicus. There is an unusually high incidence of voluntary cybernetic modifications to the bodies of Iron Hands Astartes as a result of their devotion to the Omnissiah. All Neophytes of the Chapter have their left hand removed and replaced with a cybernetic model
Ultramarines 	Roboute Guillimen 	Macragge 	The Ultramarines Chapter is known as the model for all Space Marines due to their exemplary discipline and loyalty to the Emperor of Mankind. As the largest Legion at the time of the Second Founding they produced the largest number of Second Founding Chapters. This Chapter's elite 1st Company was wiped out by the Tyranids during the legendary Battle for Macragge of the First Tyrannic War; it has taken a century to fully reconstitute that company.
Salamanders 	Vulkan 	Nocturne 	The Salamaders are a technically-adept Chapter with a preference for short-ranged combat, heat-based weaponry like melta guns, and energized warhammers. They are unusually devoted to the welfare of the civilian population of the Imperium because of their own close connections to the people of their homeworld of Nocturne.
Raven Guard 	Corax 	Deliveran 	The Raven Guard specializes in hit-and-run assaults, and they prefer the use of jump packs and lightning claws. They most commonly deploy into battle from orbit using drop pods.
=== Traitor Legions ===
These Space Marine Legions sided with Horus and the Forces of Chaos during the Horus Heresy. After their defeat in the Battle of Terra, the Traitor Legions fled into the Eye of Terror and became the primary forces of the Chaos Space Marines.
Chapter Name	Primarch		
 	 		
 	 		
 	 		
 	 		
 	 		
 	 		
 	 		
 	 		
 	 		
 	 		
Note: The Traitor Legions' homeworlds were later destroyed in a purge by Imperial forces to eliminate all traces of Chaos corruption in the Imperium following the Horus Heresy, with the exception of the Alpha Legion's homeworld, which was never discovered.
=== Second and Later Foundings ===
After the Horus Heresy, it was determined that the Space Marine Legions were too powerful and dangerous to the stability of the Imperium to be controlled by any one man. In what is known as the Second Founding, the remaining Loyalist Legions were broken up into the separate 1,000-man Chapters which remain the primary organisation of the Adeptus Astartes to this day. In the 24 subsequent Successor Foundings that have occurred since the Second Founding, the Imperium has created many new Chapters of Space Marines, using gene-seed sampled by the Adeptus Mechanicusfrom the existing ones. Many of these Successor Chapters still keep the memory of their progenitor Legion or Chapter alive in their rituals and regalia, and maintain the same methods of operation and battle, as well as their overall defining cultural and genetic traits. For a list of all the known Space Marine Chapters please see the List of Space Marine Chapters.
== Chapter Relics ==
The sacred artefacts of the Adeptus Astartes are items of incredible rarity. The following relics have belonged to different Space Marine Chapters across the galaxy at different times. Each Chapter will possess only one of the following relics at a time, for they are unique items, the only one of their kind in all the galaxy.
* The Burning Blade - This ancient broadsword is so large and dense that only a Space Marine could lift it, let alone wield it in battle. It was recovered from the wreckage of Horus' Battle Barge, the only unblemished artefact in a chamber crawling with the filthy taint of Chaos. Some Artificers have posited that it was wielded by the Emperor Himself, and that it is the Master of Mankind's greatness that shines out from its sacred steel. That the blade has a mighty origin is beyond doubt. In the heat of battle, the sword blazes so bright that it can melt even the ceramite armour of the Battle-Brother who wields it. Nonetheless, the sacred artefact still sees regular use; even mortal danger cannot stay the wrath of the Space Marines for long, and the damage its wielder can wreak on the foe is beyond compare. 
* The Armour Indomitus - The Armour Indomitus is an ancient suit of Artificer Armour forged long before the Horus Heresy. Those Masters of the Forge who have completed a pilgrimage in order to study it first-hand maintain that this battle plate has provided the blueprint for each model of Power Armour since its inception during the Unification Wars, and that its in-built Machine Spirit (Artificial Intelligence) is so complex that it must be blessed every morning and every evening to ensure the suit maintains peak performance. Unlike the plasteel and ceramite of modern Power Armour, the Armour Indomitus is made from layered plates of raw adamantium, making it extremely heavy but all but unbreachable by conventional weaponry. In the face of even heavier fire, it also incorporates a shimmering force field, the secrets of which have long been lost to modern Artificers. 
* The Shield Eternal - The Shield Eternal is believed to have been a gift from Rogal Dorn to his seneschal during the dark days of the Horus Heresy. This magnificently-worked Storm Shield is a bulwark against which all the wrath of a hateful galaxy can crash. Its warding powers turn aside the maleficent attentions of the witch and the daemon, safeguarding its wearer from mortal blows and perfidious Warp-craft alike. 
* The Primarch's Wrath - The ancient Bolter known as the Primarch's Wrath is believed to have come from the personal weapons collection of Roboute Guilliman and has dispensed thunderous death to the foes of Mankind for millennia. Chased in Theldrite moonsilver and inscribed in microscopic lettering with every treatise on tactics that Guilliman ever penned, this weapon's quality is such that it allows its wielder to sweep away great swathes of the enemy with a storm of lethal fragmenting bolts. 
* Teeth of Terra - The origins of the Teeth of Terra lie shrouded in mystery. Mentions of this large, obsidian-toothed Chainsword can be found dotted throughout the histories of many Space Marine Chapters, yet the weapon itself can be traced to no artisan's hand, nor be found in any Chapter's armoury, save in times of the greatest need. What is certain is that, when wielded in battle by a true hero of the Imperium, the Teeth of Terra strikes with the force of a thunderbolt. The more formidable the odds its wielder faces, the louder the blade's engines growl in its hunger to lay low the foes of Mankind. 
* Standard of the Emperor Ascendant - Woven from threads of spun adamantium in the early days of the Unification of Terra, this banner was carried at the head of the Emperor's personal guard. It is said that its constant proximity to the Master of Mankind has imbued within it indelible traces of His incredibly potent psychic signature. Whatever the truth of this, its presence is a constant inspiration to those loyal to the Emperor's cause, instilling within them vigour, valour and determination even as their foes quail in its presence.
== Honours and Badges ==
* Purity Seal - The Purity Seal is not so much an honour as a blessing given by the Chapter's Chaplains. Before a campaign the Chaplains pass through the ranks chanting litanies and invocations. Honoured individuals are marked by the Chaplains for special blessings recorded on the parchment streamers and affixed to their armour with the great wax seal which are often replaced with a more permanent electrum casting of the seal after the battle.
* Marksman's Honour - This device is the Marksman's Honour. Acts of remarkably accurate shooting or consistent performance with targetting of Astartes weapons are honoured with this award. The Codex Astartes insists that those warriors who prove their accuracy in combat should be singled out so that their skill may be instantly commanded when necessary. The badges themselves are believed to have been constructed by taking gold Bolter cases, fired in battle from the Boltgun of Roboute Guilliman himself, and encasing them in the award.
* Imperial Laurel - Deeds of valour leading to a great victory for the Imperium are rewarded with the Imperial Laurel. A Battle-Brother who bears this honour has literally earned his laurels. The wreath is often worn as a crown or sculpted into the Ceramite of an Astartes's helmet. The Wreathed Skull is also a common form of the same honour. The Codex Astartes demands that Company and Chapter Standards be borne into battle only by Astartes who have been awarded the Imperial Laurel.
* Iron Halo - The simple badge called the Iron Halo has its origins in the earliest days of the Imperium. Often painted onto an Astartes' armour as a red badge, the Iron Halo is the award granted for an exceptional battlefield leader and strategist. This award is given to those Battle-Brothers who demonstrate exceptional initiative. It is displayed on the shoulder armour or behind the helmet of the Astartes who has earned it as a mark of rank.
* Iron Skull - A traditional badge of ancient origin, the Iron Skull is awarded for the display of exceptional leadership in combat. It is the Codex Astartes-required insignia for a Space Marine Sergeant and is often displayed on the shoulder armour or helmet of an Astartes of this rank. The classical convention is to represent the Iron Skull as a red heraldic device.
* The Imperialis - The Imperialis was originally the campaign badge used by the Loyalist Space Marine Legions during the Horus Heresy. Over time it has evolved into the "honour of righteous victory" and is awarded to any Space Marine who has participated in an honoured victory for his Chapter. Instead of being presented as a medal or badge, it is most commonly carved into the deserving Space Marine's chest plate, replacing the armour's standard Imperial Aquila symbol (if the Astartes is wearing Mark VI or Mark VII Pattern Power Armour). It can also be seen engraved on the weapons of Astartes who have earned the badge, and also on banners or atop their heraldry finnials. It is intended to represent both the Imperium of Man as a whole with the wings of the Aquila and the Emperor's sacrifice for humanity at the end of the Horus Heresy, which is embodied by the skull icon.
* Skull and Motto - In addition to the specific badge of the Iron Skull, there are many other icons and emblems which incorporate the skull, a common Imperil motif intended to represent the sacrifice made by the Emperor for humanity's sake during the Horus Heresy. As honours these decorations often have a multitude of uses and meanings. Often combined with simple mottoes, the skull honour can be seen on shoulder plates, helmets, kneepads and even on Bolter cases or vehicles.
* Prime Helix - The Prime Helix is the emblem of the Apothecaries of a Chapter. The bright red design represents both the gene-seed itself and, to some extent, the sacrifice every Space Marine is prepared to make to ensure the Chapter's future.
* Machina Opus - The Machina Opus is the mark of a Tech-priest Adept. It is awarded to each Techmarine as he completes his mysterious training with the Adeptus Mechanicus on Mars. Bearers of the Machina Opus are accorded great respect by the Tech-priests and they alone are allowed free passage through the Red Planet's Ring of Iron and into the great workshops of the Martian Hive.
* Crux Terminatus - This is one of the most famous of all Space Marine icons. Only the honoured 1st Company Veterans of a Space Marine Chapter fight in suits of Terminator Armour and wear this badge. The symbol has various forms and designs but all versions are carved from great chunks of stone. Within each badge is bound an infinitesimal fragment of the suit of Power Armour worn by the Emperor during his climatic battle with the arch-traitor Horus over ten millennia ago high above Terra. Sergeants and Captains bear modified versions of the design to signify their rank and authority. Smaller representations of the Crux are frequently worn by the Veterans when they fight in standard Power Armour to display their elite status. These small, metallic icons can be hung from banner tops, weapons and belts.
* Service Studs - Service Studs are small metallic rivets that are attached directly to an Astartes' cranium to record his years of service to his Chapter. A single stud records, 10, 50 or 100 years of service depending on its design and the Chapter traditions. The awarding of service studs is described in the Codex Astartes but is not set out as an official requirement or regulation of the Chapter. In recent centuries the awarding of service studs has been on the decline and fewer Chapters continue the practice.
* Tattoos - Tattoos are not official Chapter honours but traditional markings derived from the Chapter's ancient practices. Some tattoos may even be vestiges of of pre-Space Marine tribal markings or hive city gang affiliations. Space Marines are recruited from hundreds of different human cultures across the galaxy so it is no surprise to see this diversity reflected in some Astartes retaining the tattoos, scarification or warpaint of their homeworld.