Horus Heresy Chronology - Heresy Chronology: Presented below is a chronological listing of the events of the Age of Darkness which fell upon the Imperium of Man during the Horus Heresy of the early 31st Millennium.The following information was compiled by manifold and diverse hands at the order of Malcador the Sigillite and the Acting Council of Terra following the outbreak, as well as during, the major events of the Horus Heresy. As more information surrounding this dark era of Human history is uncovered in newly discovered Imperial records, it will be added to the chronology.005-006.M31 Isstvan III Atrocity - The Warmaster Horus mustered four entire Legiones Astartes to put down a rebellion against Imperial rule at Isstvan III, and having turned the primarchs of those Legions to his treacherous cause, engineered the purging of tens of thousands of Legionaries not trusted to follow them into treason because of their continued loyalty to Terra and the Emperor. The ancient magicks of the Isstvanian Sirenhold are unleashed against the forces of the Sons of Horus, Emperor's Children, Death Guard and World Eaters. The battle against the rebel planetary governor Vardus Praal and his Slaaneshi Warsingers is won, but is ultimately in vain when the four Legions unleash a terrible virus bombing of Isstvan III while the Loyalist Astartes are engaged against the rebels. All does not go to plan, however, and many of the Loyalists survive to force Horus to engage them in a vicious battle lasting for several solar months among the ruins of the planet's capital, the Choral City, before they are finally wiped out by orbital bombardments when the obstructive planet-wide clouds unleashed by the virus-bombing clear. At the same time, a small number of these Loyalists escape the carnage to carry word of the Traitors' actions to Terra aboard the frigate Eisenstein. This action marks the formal start of the great civil conflict that will later be named the Horus Heresy.005.M31 Flight of the Eisenstein - Nathaniel Garro, battle-captain of the Death Guard's 7th Great Company, fled Isstvan III with 70 Loyalist Death Guard Astartes and Loyalist mortals such as the Remembrancers Euphrati Keeler, Mersadie Oliton and the Iterator Kyril Sindermann aboard the Death Guard frigate Eisenstein after having witnessed the Warmaster Horus' treachery first-hand. He braved the Warp to escape the Traitor forces who pursued him in order to bring word to the Emperor of his once favoured-son's duplicity. He encountered the Primarch Rogal Dorn and his Imperial Fists Legion and informed Dorn of the Isstvan III Atrocity. Dorn brings Nathaniel Garro to the Somnus Citadel on Luna, home of the Sisters of Silence. Garro was later brought before the Regent of Terra, Malcador the Sigillite and recounted his tale of woe. The Imperium began to fortify itself against the inevitable attack of the Traitor Legions. Nathaniel Garro is chosen to become the Agentia Primus of Malcador's newly-formed Knights-Errant, a group of Space Marines drawn from all the Legions that will serve as his personal agents and special operators across the Imperium in this time of civil war.005.M31 Battle of Diamat - When word reaches the Dark Angels Legion of the Isstvan III Atrocity, Lion El'Jonson and the Ist Legion are bogged down fighting a campaign against the Gordian League. Therefore, the Lion leads a small war fleet of 16 vessels against the Forge World of Diamat, in order to seize Mechanicum Ordinatii heavy siege engines, and deny them to the Traitors. He encounters some resistance from vessels loyal to the Traitor cause, as well as Traitor Imperial Army forces and a Sons of Horus company on the planet's surface. The Lion orders the destruction of the planet's primary forge cities, which annihilates the Traitor forces in a great conflagration and denies to Horus Diamat's manufacturing capabilities. In the battle's aftermath, El'Jonson encounters the Iron Warriors' Legion fleet, led by Perturabo, who are on their way to Isstvan V to "pacify" the treacherous Warmaster. Unaware of the Iron Warriors' true loyalties, the Lion unwittingly hands over the captured Ordinatii intended to be used against Horus to those who actually intend to join the Archtraitor's cause.006-007.M31 - Chondax Campaign - Waylaid fighting Orks on the galactic fringe for five standard years, the White Scars discover the hand of the Alpha Legion behind their misfortunes. The Alpha Legion, supposedly driven by the commands of both the Warmaster Horus and the xenos organisation known as the Cabal, openly engaged the White Scars in the Chondax System after standard years of shadowed ambushes. Their exact purpose is unclear it would seem, even to the XXth Legion itself. For unknown reasons, the Alpha Legion cease their blockade -- allowing the White Scars' Primarch Jaghatai Khan to receive word of the Warmaster Horus' betrayal of the Emperor when in the wake of the engagement, they established contact with the Primarch Leman Russ on Terra in the aftermath of the Space Wolves' destruction of Prospero. Faced with the dilemma of aiding the weakened Space Wolves against a powerful force of Alpha Legion attackers, or returning to Terra as ordered by Rogal Dorn, their Jaghatai Khan chooses a third option. Seeking out answers for himself as to who is truly loyal to the Emperor and who is not, he orders his fleet to set course for Prospero to ascertain what has truly occurred there.006-014.M31 Imperial Fists' Blockade of Cthonia - The Imperial Fists blockade Cthonia, homeworld to the Sons of Horus, but the Traitors are too heavily entrenched to be removed. The VII Legion maintain their occupation for standard years, preventing all attempts to break free, until a Sons of Horus strike force arrives to break the siege and turn the tables on the sons of Rogal Dorn.566.006.M31 Drop Site Massacre of Isstvan V - With Terra warned of the Warmaster Horus' treachery at Isstvan III, eight entire Space Marine Legions, half of the known forces of the Legiones Astartes, are ordered by Terra to crush the Traitors' rebellion at Isstvan V, but unbeknownst to the rest, Horus has already turned three of these Legions to his service and ensured the fourth is delayed. The first wave of Loyalist Legions -- the Iron Hands, Raven Guard and Salamanders -- makes planetfall but is betrayed by the second wave coming behind them -- the Alpha Legion, Night Lords, Iron Warriors and elements of the Word Bearers -- in the bloodiest three solar hours of war ever fought by the Legiones Astartes. In the aftermath of the great betrayal, three Legions are almost entirely wiped out, one primarch, Ferrus Manus, is slain in the battle by Fulgrim and two others -- Vulkan and Corvus Corax -- are missing in action, though in fact Coraxmanaed to escape off-world with the remnants of his Legion. The survivors of the Iron Hands, Raven Guard and Salamanders who manage to escape off-world or remained elsewhere in the galaxy become known as the "Shattered Legions."ca.006.M31 Battle of Ravendelve - Following the calamitous events on Isstvan V and the surviving Raven Guard's flight to Terra to bring word of the disaster, the shattered XIXth Legion returned to their homeworld of Deliverance. Unknown to them, the insidious Alpha Legion had inserted several of their own Legionaries into the Raven Guard Legion, surgically disguised as Raven Guard Astartes who had died on the black sands of Isstvan V. Gathering intelligence on the Primarch Corax's efforts to reconstitute his Legion utilising a sample of pure, undifferentiated primarch DNA given to him by the Emperor Himself, the Alpha Legion operatives patiently waited until the Raven Guard had achieved a genetic breakthrough. In the meantime, they fomented rebellion amongst the old tech-guilds of Kiavahr, the Forge World that the moon of Deliverance circled, while assembling Alpha Legion forces nearby for an unsuspected surgical strike. The Alpha Legion imposters successfully and secretly tainted the undifferentiated primarch DNA, which resulted in the disastrous mutation of newly-inducted Raven Guard aspirants into hideously transformed creatures. At the same time, the Alpha Legion's plans reached their climax. The Kiavahr rebellion was well under way, supported by the newly-arrived Alpha Legion forces, who were camouflaged as Raven Guard. The Loyalist Raven Guard successfully put down the rebellion and killed all the Alpha Legion operatives, but were no closer to reconstituing their Legion's numbers or making a difference in the fight to come against the forces of Horus.ca. 006-009.M31 Imprisonment of Vulkan - The Salamanders' Primarch Vulkan managed to survive the nucleonic bombardment of the Urgall Depression on Isstvan V during the Drop Site Massacre, due to his unknown regenerative abilities as an immortal Perpetual, a status he had inherited from his genetic father the Emperor, also a Perpetual. When Vulkan finally awoke in the aftermath of the explosion, he found himself surrounded by hundreds of Iron Warriors and Night Lords Legionaries. Prepared to fight to the death, the Traitor Marines proceeded to shoot, stab and bludgeon the primarch into unconsciousness. Seeing the opportunity to torment his brother, Konrad Curze, primarch of the Night Lords, took Vulkan prisoner, and secured him aboard his flagship Nightfall. Over a period of several solar months, Curze would proceed to torture Vulkan mercilessly in an attempt to break his body, mind and spirit. But eventually Vulkan effected his escape, and with his warhammer Dawnbringer, was able to teleport himself to the upper orbit above the capital world of the Realm of Ultramar -- Macragge. Before burning up in the planet's atmosphere upon reentry, he was confident that he would wake up in the care of his Ultramarines cousins, for immortality was his birthright.006-011.M31 Succession Wars - A vital space lane is seized by the Alpha Legion, who through sheer misfortune cross paths with a Loyalist company of Iron Warriors, forcing an unexpected and bloody struggle. The region changes hands many times over the course of the next five Terran years, leaving the core world of Paramar V little more than a devastated husk.006.M31 First Battle of Paramar - Alpha Legion forces allied with the Traitor Dark Mechanicum of Taghmata Satarael and the Titans of the Legio Fureans mount a surprise attack on the strategically vital lynchpin star system of Paramar before their true allegiance becomes known to the defenders. Paramar is a vast arms cache of the Great Crusade and a vital Imperial communications hub. The Pharaeon of Paramar, its primary void station, is quickly taken, but a full planetary assault of Paramar V becomes necessary as Loyalist Mechanicum and Legio Gryphonicus Titan forces, as well as the unexpected intervention of a Loyalist cadre of the Iron Warriors Legion, offers the invaders strong resistance. The valiant defence, however, is ultimately overwhelmed and Paramar V falls to the Traitors, cutting off much of the most stable Warp transit routes to the northern Imperium.006.M31 ALL DATA REDACTED006.M31 Sundering of Zhao-Arkhad - <NO DATA AVAILABLE>006.M31 Battle of Lesser Damantyne - When the Iron Warriors' Warsmith Krendl arrived at Lesser Damantyne with the Iron Warriors' 51st Expeditionary Fleet to secure the world's formidable fortress, known as the Schadenhold, as a resupply point for the Warmaster Horus' Traitor Legions, its Loyalist Iron Warriors commander, Warsmith Barabas Dantioch, refused to comply. This resulted in an internecine conflict between the two opposing Iron Warriors forces. Dantioch commanded his meagre forces against the entire might of the 51st Expeditionary Fleet and the 14th Grand Company of the Iron Warriors for 366 solar days, until the Traitors deployed an Imperator-class Titan to destroy the Schadenhold. Though the fortress fell, Dantioch and the surviving Loyalist Iron Warriors teleported aboard the Traitors' flagship and commandeered it, fleeing towards Terra.ca. 007.M31 Raid on Cruciax - The raid on Cruciax, a world that harboured a listening post of the Word Bearers Legion, marked the Raven Guard's return to the battlefield after the crippling losses suffered during the Drop Site Massacre. Intended as a field test to further assess the capabilities and discipline of the new contingent of the XIXth Legion, the "Raptors," the raid was a great success, and wiped-out the Word Bearers' garrison and destroyed the facility in less than twenty solar minutes. The first three hundred members of the Raptors, who were all genetically perfect, were declared battle-ready following this action and the Raven Guard quickly turned its eye to a more important target -- the Siege of the Perfect Fortress on the world of Narsis.007.M31 First Siege of Hydra Cordatus - Shortly after the disastrous events of the Drop Site Massacre of Isstvan V had played out to their tragic conclusion, the traitorous Iron Warriors Legion saw the opportunity to humble their hated rivals, the Imperial Fists, upon the isolated world of Hydra Cordatus. The Iron Warriors made planetfall and proceeded to be held at bay for nearly three solar months, thanks to the courage of its Loyalist defenders, the geography and the ingenuity of the fortress builders of the Cadmean Citadel. The few surviving Imperial Fists defenders were slaughtered to the last Astartes and the surviving refugees were enslaved by the Iron Warriors before they moved on to their next objective. Hydra Cordatus was reduced to a barren Desert World by the ferocity of the Traitor Legion's assault.007.M31 Battle of Phall - Having been cast off-course and stymied by Warp Storms en route to Isstvan V by the machinations of the Warmaster Horus' dark allies in the Empyrean, the Imperial Fists' Retribution Fleet is becalmed for long solar months at the Phall System. Only by maintaining a constant state of readiness and the genius of their commander is the fleet saved from utter destruction when the Traitor Iron Warriors attack their hated rivals. Dozens of capital ships are lost as boarding actions take place on both sides. The Imperial Fists board Perturabo's flagship and almost secure victory. But at the height of the engagement, an astrotelepathic message from Terra finally breaks through the turbulent Warp, as Rogal Dorn, the primarch of the Imperial Fists, orders his fleet to return to the Throneworld at once.ca. 007.M31 The Angel Exterminatus - Both the Iron Warriors and the Emperor's Children enter the great Warp rift named by Perturabo as the "Eye of Terror," on a quest to seek out an ancient Aeldari weapon known as the Angel Exterminatus. They are led deep within the hellish region where the Empyrean bleeds into realspace, where they discover the remnants of an Aeldari Crone World called Iydris. While exploring the planet's ancient ruins for the legendary weapon, they are set upon by guardian Ghost Warriors and other Aeldari Wraith constructs and by elements of the Shattered Legions that have been tracking their activities for many solar months. Unknowingly, Fulgrim had been using his primarch brother's life force in order to finally achieve daemonic apotheosis, and he becomes the first of the Traitor primarchs to ascend to the position of Daemon Prince during this quest. The act destroys Iydris, and releases so much Warp energy that a black hole singularity is formed. Perturabo escapes from the world with his Legion after watching Fulgrim and his warriors teleport somewhere else, and their fleet dives directly into the heart of the black hole. They emerge on the other side of the galaxy, near the verdant world of Tallarn.007-009.M31 The Manachean War and the Dark Compliances - His treachery fully revealed at last to the Imperium after the battles in the Isstvan System, the Warmaster Horus begins his relentless seven-year-long advance on Terra, forcing his Dark Compliance of countless regions across the northern Imperium to provide his forces with a resource base to fight what will now become a protracted and relentless interstellar civil war. Foremost among his targets are the Manachean Commonwealth, the Coronid Deeps and their surrounding regions, where a particularly savage campaign is conducted by the Sons of Horus and Death Guard which brings the economically vital worlds of the Manachean Commonwealth to fuel the Traitors' cause. This wider campaign also places the fleet anchorage of Port Maw under the Warmaster's talon and sees the stubbornly Loyalist Forge Worlds of Lucius and Mezoa isolated and besieged, while the Traitor-aligned Forge World of Cyclothrathe begins to carve out its own pocket empire in the region.007.M31 Destruction of the Furious Abyss - Following the destruction of the Auretian Techocracy and securing of their rare STC templates, Lorgar, primarch of the Word Bearers Legion, secured a secret alliance with the traitorous Fabricator-General Kelbor-Hal of the Martian Mechanicum. He commissioned this faction, increasingly called the "Dark Mechancium" by those Tech-priests who still viewed the Emperor as the Omnissiah, to construct a trio of immense Abyss-class Battleships for the service of his Legion. The Furious Abyss was the first such vessel of its kind. The Word Bearers had been secretly ordered by the rebellious Warmaster Horus to bring their unfettered wrath down upon their hated rivals, the Ultramarines Legion. The Furious Abyss was to play an instrumental role in the Battle of Calth and the Traitor Legion's destructive campaign that was intended to see the Ultramarines' capital world of Macragge destroyed. But before the mighty battleship could reach its destination, the secret of its existence had been discovered. The Word Bearers' vessel was infiltrated by a small Loyalist strike force of Space Marine Legionaries, who proceeded to sabotage the ship's plasma generatorium, which began a chain-reaction that resulted in the destruction of the massive vessel.007.M31 The Calth Conjunction, Battle of Calth and the Birth of the Ruinstorm - Mustering at the world of Calth in the Realm of Ultramar on orders issued by the Warmaster Horus before the Isstvan III Atrocity, the Ultramarines and Word Bearers prepared for a campaign against the Orks of the Ghaslakh xeno-hold. The Ultramarines were unaware of the Word Bearers' true allegiance and utterly unprepared for betrayal, and suffered horrific losses as a result. The Traitors' real objective was to incur enough casualties on the world after murdering Calth's Veridia star as a sacrificial offering to the Ruinous Powers that would bring about the birth of the Ruinstorm, a Warp Storm so large it would sever the galaxy in half and render all long-range Warp travel unpredictably dangerous, and trans-luminal astrotelepathic communication all but impossible. The death of the system's star bathes Calth's once-vibrant biosphere in deadly radiation. This action paved the way for Horus' rapid advance on Terra. The so-called "Age of Darkness" begins.007-017.M31 The Underworld War on Calth - Following the events of the Battle of Calth, the Word Bearers performed one last act of spite and caused the planet's primary star to become unstable. The surface of Calth was ravaged by the radiation emitted by the slow death of the Veridia star. The continuing Battle of Calth between trapped forces of those Ultramarines and Word Bearers still locked in a death-struggle descended into the extensive arcologies deep beneath the planet's surface. This so-called "Underworld War" ground on for ten solar years before the last of the Traitors was finally hunted down and slain, a period that extends beyond even the end of the Heresy itself.007-008.M31 Shadow Crusade - The Word Bearers and World Eaters, led by the Primarchs Lorgar and Angron, invade the Five Hundred Worlds of the Realm of Ultramar with the aim of utterly destroying the domain of the Ultramarines Legion and drawing Loyalist forces away from the Warmaster Horus' advance on Terra. The Traitors burn every world their fleet encounters. During the conflict, which occurrs concurrently with the perfidious attack of the Word Bearers at the Calth Muster during the Battle of Calth, scores of worlds are ravaged and the involvement of the Ruinous Powers in aid of the Traitor cause is first widely manifested in open war, transfiguring both of the Traitor Legions involved. Roboute Guilliman confronts his brothers at Nuceria, Angron's hated homeworld, and halts their rampage, but not before dark powers possess Angron and transform him into a daemonic avatar of bloodshed, a Daemon Prince of Khorne.007-011.M31 The Ruinstorm - Fuelled by the sorcerous rituals of the Word Bearers and the carnage unleashed by the Battle of Calth and the Shadow Crusade in Ultramar, a vast Warp phenomenon dubbed the "Ruinstorm" inhibits travel and communication across Imperial space, cutting whole regions of the galaxy off from the Astronomican's guiding light. While the Warp-touched Traitors can navigate freely, three Loyalist Space Marine Legions -- the Dark Angels, Blood Angels and Ultramarines -- are stranded far from Terra, unable to assist in its defence.007-015.M31 Solar War - The battle for the Sol System, known as the Solar War and long-threatened, begins as Traitor infiltration forces and probing raids from without, and Dark Mechanicum attacks and attempted break-outs from besieged Traitor-controlled Mars test the defences of the Throneworld of Humanity. Traitor ships assault the Segmentum Solar under the cover of refugee flotillas, bringing the war to Terra's doorstep. The Alpha Legion comes within striking distance of the Throneworld in the Battle of Pluto, only for Alpharius to meet his death at the hands of Rogal Dorn. Despite this, the Alpha Legion's command structure appears as strong as ever. Conflict within the system is not concluded until the eventual lifting of the Siege of Terra in 014.M31 and the cleansing of remaining Heretic forces from Mars in 015.M31. {See Extrapolation Addenda CVX-CVXVIII-Classified Amaranth-Gold}007-010.M31 Thramas Crusade - Horus ordered the Traitor Primarch Konrad Curze of the Night Lords to neutralise the three Forge Worlds of Thramas, thereby denying the Loyalists a major source of war machines and materiel in the eastern Imperium. They succeeded in destroying two of the region's Forge Worlds and damaging the third grievously. The Dark Angels then responded to reports of atrocities committed across the Eastern Fringe, revealed to be the work of the Night Lords. The vengeful conflict that follows lays waste to hundreds of Imperial territories, but ends with Konrad Curze and many of his senior commanders presumed dead or captured by Lion El'Jonson, while the Night Lords Legion scatters into dozens of independent warbands.007-008.M31 Siege of the Perfect Fortress - Located on the world of Narsis, the so-called "Perfect Fortress" had been erected by the IIIrd Legion, the Emperor's Children, during the Great Crusade,designed by the Primarch Fulgrim and his brother Perturabo, a genius at siege tactics. Following the XIXth Legion's catastrophic losses and the ill-fated attempt to quickly replace these losses, Corvus Corax decided that his Legion would assail the highly symbolic location to prove that it was still a formidable fighting force. Through the use of Corax's superlative military tactics and stratagems, the so-called "Perfect Fortress" fell within the solar day. The strategem used was for the impregnable fortress to come under futile attack by an Imperial Army cohort, who are run down and butchered by the Emperor's Children. The defenders return to find their vacated fortress occupied by the Raven Guard, who swiftly turn the powerful defensive weapons on their arrogant former brothers. This highly symbolic action not only marked a severe defeat for the increasingly notorious Traitor Marines of the IIIrd Legion, but also the return of the XIXth Legion to the front lines during the Heresy. It was purely an act of spite against Horus, and even though its choice to serve the Emperor nearly brought it to extinction, the Raven Guard still opposed him and proved to be a thorn in the Archtraitor's side.570.007.M31 Return of Cassian Dracos - Still ignorant of the events that occurred on Isstvan V, Lord Chaplain Nomus Rhy'tan despatched Chaplain-Lieutenant Xiaphas Jurr and 30 elite Firedrakes of the Salamanders Legion aboard the vessel Ebon Drake to ascertain the fate of their Legion. When the Ebon Drake arrived at the black sands of Isstvan V, its crew were unable to locate their missing primarch, but they were able to uncover the battered shell of the Salamanders Dreadnought Cassian Dracos, known as the Dragon Revenant, far from intact but not yet willing to surrender to his final inevitable death. Called "The Twice-Dead" and the "Avatar of the Sacred Flames" by his brothers, Cassian Dracos returned to the battlefields of the Imperium to enact his vengeance upon the Traitors, but he would not be as he once was. His time beneath the black, blood-soaked sands of Isstvan V had left him changed, fey and of unpredictable temper and able to exert a disturbing control over the creations of the Machine God and those bound to them. The presence of Cassian Dracos reinvigorated the demoralised crew of the Ebon Drake, and they continued their search for their missing Primarch Vulkan, convinced that he yet lived.007.M31 Battle of the Alaxxes Nebula - As the Space Wolves are still licking their wounds following their heavy losses during the Fall of Prospero, they are ambushed by a sizable Alpha Legion strike force and are subsequently routed at Yarant. Primarch Leman Russ organised a tactical retreat and fled towards the Alaxxes Nebula. The Alpha Legion gave chase and soon the VIth Legion found itself in a precarious predicament -- they are effectively cut-off and surrounded. Russ reluctantly sent a distress call for assistance to his brother-Primarch Jaghatai Khan of the White Scars Legion. Unsure of who was in the right, Jaghatai declined to assist the Space Wolves and instead set course for Prospero to determine the truth for himself in regards to the Warmaster Horus' proclaimed heresy. The Space Wolves were eventually forced to flee in order to survive. A final confrontation eventually erupted between the Loyalist and Traitor forces as the Space Wolves vowed to take as many of their foes with them before they were annihilated. Alpharius himself teleported aboard Leman Russ' flagship, but was rebuffed long enough for the Space Wolves' salvation to arrive. The sons of Russ received relief from an unexpected quarter, in the form of the Dark Angels Legion, and their mighty mobile star fort Chimaera. Answering Russ' distress signal, the combined forces of the Loyalists are able to turn the tide, and inflict serious losses on the Alpha Legion, forcing them to withdraw.007.M31 The Wolf & The Khan - The White Scars learn of the Warmaster's heresy when they establish contact with Leman Russ in the aftermath of the Space Wolves' destruction of Prospero. Faced with the dilemma of aiding the weakened Space Wolves against a powerful force of Alpha Legion attackers, or returning to Terra as ordered by Rogal Dorn, Jaghatai Khan chooses a third option. Seeking out answers for himself, he orders his fleet to set course for Prospero to ascertain what has occurred there.007.M31 Second Battle of Prospero - After Jaghatai Khan refuses to aid Leman Russ and his battered Space Wolves fleet, he finally arrived at the ravaged world of Prospero seeking answers to the truth of Horus' betrayal for himself. Teleporting down to the planet's surface with a small honour guard detachment, Jaghatai explored the ruins of the planet's former capital city of Tizca. During his explorations, the primarch became separated from his Astartes, and soon found himself trapped within a network of subterranean caverns where he was confronted by the ætherial projection of his brother, the Primarch Magnus the Red. Magnus implored his brother to choose a side and to not trust their father, the Emperor. Finding the answers he sought, Jaghatai made his way towards the surface and was reunited with his Keshig, who are soon beset by the Primarch Mortarion and a contingent of Deathshroud Terminators. The Death Guard primarch tried to persuade his brother to join the Warmaster Horus' cause, but Jhagatai refused, and proceeded to fight his brother, gravely wounding Mortarion and forcing him to withdraw. Teleporting back aboard his flagship, the White Scars' primarch then ordered his fleet to depart for Terra to honour Rogal Dorn's call for all Loyalist Legions to return to the Throneworld, having made his choice at last.007-011.M31 The Path of Heaven - Trapped far from Terra the White Scars learned that the eruption of the massive Warp Storm known as the Ruinstorm in the wake of the Battle of Calth has made all long-distance Warp travel and superluminal communication impossible. Seeing no other choice, the White Scars were forced to begin a hit-and-run guerilla campaign against the Traitor Legion forces to slow their advance on the Throneworld of Terra. The White Scars proceeded to lose nearly one-fifth of their fighting forces over the course of the next four standard years of conflict. As the Traitors adjusted to the Vth Legion's tactics, it became apparent to Jaghatai Khan that his Legion was slowly being boxed in. Desperate, the White Scars sought out one last approach to Terra, and discovered a hidden Navigator facility controlled by the Navis Nobilite within the Catallus Warp rift. Within the void station, they found the Dark Glass artefact -- a far-less powerful prototype of the Golden Throne device dating back to the Age of Technology, which was capable of accessing the Webway. The White Scars Stormseer Targutai Yesugai sacrificed himself when he sat upon the Dark Glass throne in order to open a temporary path through the Webway, which allowed the White Scars to escape from a massive Traitor fleet and exit the Empyrean at the outer edge of the Segmentum Solar.004.008.M31 Battle of Percepton Primus - A large Word Bearers contingent of the 34th Company, led by Captain Sor Talgron and Dark Apostle Jarulek, assaulted the world of Percepton Primus located in the Percepton System of Ultramar at the beginning of the Shadow Crusade. They managed to cripple the defending Ultramarines fleet in 27 solar minutes, destroying nearly half the fleet, but the fight continues on the ground, as the Ultramarines stubbornly hold out for another 163 solar days, led by the Ultramarines' 17th Chapter Master Aecus Decimus. In the final desperate solar hours of the campaign, the Ultramarines utilised phosphex, a world-killing weapon of mass destruction that their Primarch Roboute Guilliman abhorred, in order to achieve victory, though the planet was rendered a burnt cinder and uninhabitable to life. Though they were able to kill two-thirds of the Word Bearers' forces, both Talgron and Jarulek escaped the burning surface of Percepton Primus.008-013.M31 Siege of Baal - Baal, homeworld of the Blood Angels, becomes a sanctuary for Space Marines fleeing Horus' rebellion. Fearing the Shattered Legions will reorganise and pose a threat to his plans, the Warmaster besieges the planet, although every attempt to conquer Baal is rebuffed with a heavy toll of casualties.008-009.M31 Vannaheim Space Drop - The Iron Warriors launch a daring void assault against the orbital hives of the world of Vannaheim, capturing vital facilities after ten solar days of brutal fighting. A Loyalist force in the Segmentum Tempestus, including isolated elements of the Space Wolves Legion, is drawn into the conflict, launching three successive counter-assaults in order to recapture the orbital hive stations' vital altitudinal control grid. Each fails to achieve its goal and countless thousands of Loyalist lives are lost. The famed Space Wolves grand cruiser, Helicon Spear, is captured and becomes a prize of the Iron Warriors Legion during the last, disastrous attempt.008.M31 The Raven Strikes - The Raven Guard proceed to conduct a protracted campaign against the Traitor Legions and manage to secure multiple victories at Scarato, Kapel-5642A, Constanix II and Carandiru.008.M31 Blood Among the Pale Stars - A previously unidentified group of Blackshields of unknown provenance, calling themselves the Dark Brotherhood, carve out their own corsair empire on the edge of the Pale Stars and begin a long war against an Alpha Legion hunter-killer force tasked with crushing resistance to the Warmaster Horus' Dark Compliance in the region.008.M31 Ruin of Maerdan - In the third standard year of the Horus Heresy, the Imperial colony world of Maerdan on the edge of the Segmentum Solar became a savagely contested frontline between the forces of Loyalists and Traitors. Maerdan's cities became flaming ruins and its once verdant plains were turned to barren wastes, crushed and scoured by the fury of the battle as the Loyalist Titans of the Legio Gryphonicus ("War Griffons"), Legio Metalica ("Iron Skulls") and the Legio Destructor ("Beasts of Stell") clash with the Traitors of the Legio Mortis ("Death's Heads"), Legio Argentum ("Dread Lances") and the Legio Vulturum ("Gore Crows"). The Ruin of Maerdan, as the campaign comes to be known to later Imperial historitors, is one of the largest Titan battles of the early Horus Heresy, when more than 200 Titans took to the field against each other. Heavy losses were incurred by both sides and as the war moved on, it left a shattered world behind, with neither Loyalists nor Traitors able to claim a true victory. The flames of hatred between the War Griffons and the Death's Heads, once staunch allies, burn bright after Maerdan and their enmity would lead them to seek each other out time and again on the fields of battle in the dark years that followed their first clash.008.M31 Destruction of Bodt - The World Eaters' fief world and Legiones Astartes training ground on Bodt is attacked by the infamous Iron-Father Autek Mor of the Iron Hands and an allied independent Loyalist force. After a savage battle, Mor is believed to have entered the subterranean macro-vaults of the city of Tredecimmia before scouring every trace of life from the surface. Bodt's supply line of initiate recruits to the World Eaters Legion is permanently severed.008.M31 Burning Grave of Ohmn-Mat - The Forge World of Ohmn-Mat in the Ultima Segmentum falls into a state of civil war as its Synod magi are split in their support for the Loyalist and Traitor causes, drawing in contingents of Sons of Horus Dark Compliance forces and Iron Hands Isstvan V survivors as the conflict escalates. Ohmn-Mat is destroyed in the conflagration and its fires still rage even in the present.008.M31 Fall of Batzel III - Space Wolves strike forces eradicate the entire 39th Millennial of the Emperor's Children during the storming of the Vykstag Winter Palace as part of the Batzel III Campaign for control of the Brozyn-Primaris Sector of the Segmentum Obscurus. Leaderless, Batzel succumbs to infighting and ultimately genocidal civil war. While exiting the sector, the Space Wolves strike force clashes inconclusively with an unknown and elusive Legiones Astartes force which bears no recognisable heraldry.008.M31 Blight of Isessos - A series of void raids on the outskirts of the Isessos System in the Segmentum Pacificus by an Alpha Legion strike group led to severe casualties, which are returned to the colony habitats of the system's three Agri-worlds for treatment. Several of the casualties were later found to have been infected with an unknown algal strain. Within a standard year this virus wipes out the system's vast macro-output saturation fields, reducing them to poisonous slime. This results in a sector-wide famine that killed an estimated ninety billion Imperial citizens and the complete political destabilisation of the region.008.M31 Battle of Nuceria - At the climax of the Battle of Nuceria during the conclusion of the Shadow Crusade, whilst in combat with Roboute Guilliman, the Primarch Angron of the World Eaters reaches a nadir of pain, bitterness and rage orchestrated by Lorgar of the Word Bearers which forms a conduit between him and the Warp. Guilliman and his Ultramarines are forced to withdraw as his brother is ravaged by Empyreal energies and is transformed into a Daemon Prince of Khorne, the Blood God. Lorgar believed that this ascension to daemonhood was the only way to save Angron's life, who was slowly dying as a result of the deleterious effects of the Butcher's Nails implanted in his skull.008.M31 Dagonet Incident - The hidden Departmento Assassinorum clade-masters of Terra despatch their most potent Execution Force of Assassins to the recently fallen world of Dagonet in an attempt to strike down the Warmaster Horus before his rebellion can do any more damage to the Imperium. They are unsuccessful, but from their failure Terra learns much of the new and dreadful powers of the Empyrean wielded by its foe.009.M31 Battle of Perditus - When the Dark Angels received intelligence on Traitor movements from an astropathic message from the nearby Perditus System, they acted accordingly and moved to intercept. Upon arrival, they interrupted the 38-solar-day-long conflict between the Iron Hands' 98th Clan-Company, led by Casalir Lorramech, and a large Death Guard contingent, commanded by First Captain Calas Typhon on the Mechanicum station of Perditus. Both sides had been fighting over an ancient sentient device, known as the Tuchulcha Engine. This device was part of a triumvirate of similar sentient devices (another being the Ouroboros and a third, unnamed engine) which when combined could create temporal rifts that bridged space and time. On its own, the Tuchulcha Engine was capable of precise and extremely efficient Warp jumps. The matter is eventually resolved by the arrival of an overwhelming Dark Angels fleet led by Lion El'Jonson. The Lion took Perditus under his own protection and demanded the retreat of both the Xth and the XIVth Legions. Faced with the prospect of fighting the entirety of the much larger Ist Legion fleet, both sides lifted off from the planet's surface following the Lion's request. Wary of both sides' motives, especially First Captain Typhon's, the Lion prevented the device from falling into the Death Guard officer's hands. El'Jonson proceeded to serve his own ambitions and requisitioned the device for his personal use. The Lion ordered the destruction of Perditus, much to the consternation of both the Loyalist and Traitor commanders.009.M31 Breaking of Anvillus - The vital Forge Worlds of the Anvillus System erupt into a war of mutual annihilation. Strangely, the magi lords reject offers of alliance from both Loyalist and Traitor causes, instead destroying any who attempt to intervene. No onlookers are able to determine what the opposing factions are warring over, or why the conflict began.009-013.M31 Siege of Inwit - Dozens of Traitor fleets attack the systems of the Inwit Cluster, hungry for the prize of the Imperial Fists' homeworld. The siege increases steadily in intensity for four standard years before the Warmaster's direct assault on Terra draws Traitor forces away, leaving the Inwit Cluster a string of burning, wasted worlds.009.M31 Tsagualsa Incident - Forces of the Dark Angels Legion ambush the Night Lords at the world of Tsagualsa in the Eastern Fringe, inflicting severe losses. The primarchs Lion El'Jonson of the Dark Angels and the Konrad Curze himself clash in direct contest of arms after a failed parley, and both are so grievously wounded that their warriors are forced to drag them clear of each other before the matter can be settled.009.M31 Defence of Nagathar - Severed from the main body of their Legion by the unleashing of the Ruinstorm, a Dark Angels  strike force found shelter in the Nagathar System which had become a safe haven for several Loyalist splinter forces, the most important being drawn from the Imperial Fists. The many Loyalist factions banded together to defend Nagathar from a powerful incursion led by the Word Bearers Legion, which had hoped to prey on the system's millions of inhabitants to fuel yet another of their sorcerous Chaos rites.009.M31 Xana Incursion - Intelligence reaches Terra that the Renegade Forge World of Xana II on the western fringe of the Imperium has reached an accord with the Traitor forces to supply the Warmaster Horus' armies with its vast output of arms and materiel. The bargain is sealed with the delivery by Xana II of a number of newly created powerful Ordinatus class weapons undergoing final field tests. In what is effectively a suicide mission, a handpicked force of Legiones Astartes, including many Blackshields -- in this case Space Marines who have chosen to remain loyal to the Emperor despite their parent Legion's treachery -- is despatched under great secrecy to destroy the war machines and drive a wedge between Xana II and the Traitors.009.M31 Defence of Coronis Agathon - When the Parliament of Electors of the world of Coronis Agathon, capital world of the Agathean Domain, erupts into arguments over whether or not to stay loyal to the Emperor or ally with the Warmaster Horus, Ireton MaSade, the old former lord marshal militant, nearly two standard centuries in age and retired from public life, and all but a recluse for nearly two solar decades, interrupts the warring chamber. Bedecked in the old livery of his Solar Auxilia regiment and flanked by troops of the Solar Auxilia Veletaris, MaSade confronted the weak-willed politicians of the Agathean Domain and denounced them for their moral weakness, and declares them all Traitors to the Emperor. Before the lords of Agathon can reply or protest, the funeral guard turn their Volkite Weapons on the nobles of the Parliament of Electors and burned them to ash. Agathon and the worlds around it are placed under martial law under direct control of the "Old Guard" of the 60th Expeditionary Fleet and its direct descendants. Agathon is placed on a war footing, its people intent on having their vengeance against the Traitors.009.M31 Battle of Arissak - Having pursued the numerous attack cells made up of Iron Hands, Salamanders and Raven Guard survivors of Isstvan V, Captain Tybalt Marr of the Sons of Horus finally brings them to battle, destroying the massed fleet of Shadrak Meduson's so-called "Shattered Legions" force at Arissak.009.M31 Incident at Dwell - Horus arrives upon the world of Dwell, a planet settled during the Age of Technology by settlers from the nearby Knight World of Molech. The Warmaster was intent upon utilising the ancient data repository on Dwell that contained information that would lead him in search of what he believed to be the true source of the Emperor's power. This data would lead him back to Molech, where he had unknowingly taken part in that planet's Imperial Compliance campaign solar decades earlier, before his memories had been psychically suppressed by the Emperor. Shortly after the infamous Drop Site Massacre campaign on Isstvan V, the Sons of Horus were also forced to recoup their losses. Having escaped death at Arissak, one of Shadrak Meduson's surviving Shattered Legions attack cells launches a daring assassination attempt on Horus at Dwell. With his brother-primarchs Fulgrim and Mortarion at his side, Horus prevails, but having had the true threat revealed to him, he grants Tybalt Marr permission to take any action he deemed appropriate to eradicate the so-called "Shattered Legions."009.M31 Battle of Molech - Horus led both the Sons of Horus and the Death Guard Legions in the invasion of the Fortress World and Knight World of Molech. Having recovered some of his memories in regards to the earlier Imperial Compliance campaign that took place on Molech commanded by the Emperor many solar decades earlier, Horus uncovered the truth the Emperor had sought to keep even from his gene-sons about the hidden, subterranean Warp Gate present on the world that led into the Realm of Chaos and that the Emperor used millennia before to gain much of His secret knowledge and power -- including the arcane techniques required to create the primarchs. Wanting this power for himself, Horus launched a massive strike on the unsuspecting world. The Traitors committed an enormous invasion force, including the bulk of the Sons of Horus and Death Guard Legions, and Titans of the Legio Mortis ("Death's Heads"), Legio Vulcanum II ("Lords of Ruin"), Legio Interfector ("Murder Lords"), and Legio Vulpa ("Death Stalkers"), which were opposed by elements of the Ultramarines and Blood Angels Legions, Titans of the Legio Gryphonicus ("War Griffons"), Legio Fortidus ("Dauntless"), and Legio Crucius ("Warmongers"), and hosts of Knights from almost a dozen houses, with both sides bolstered by hundreds of thousands of allied mortal troops. At the height of the battle, House Devine revealed that its true allegiance was to the Warmaster, its treachery unveiled at a pivotal moment, heralding a slaughter from which only a handful of Loyalists escaped. The Warmaster went on to claim the world and enter the Warp Gate, from which he emerged fully empowered as the chosen champion of the four major Chaos Gods in the guise of Chaos Undivided. Later, a force of the elite Knights-Errant, a secretly founded order of Loyalist Space Marine agents, were despatched to Molech by Malcador the Sigillite, the Regent of Terra, to prepare the way for a direct assault by the Space Wolves against the Warmaster's flagship. Having recently won the full blessings of the Ruinous Powers while within the Realm of Chaos after transiting through the Molech Warp Gate, Horus proved undefeatable and only a handful of Knights-Errant, including Garviel Loken, managed to escape the corridors of the Vengeful Spirit to bring news of the Warmaster's redoubled strength back to an increasingly beleaguered Terra.009.M31 Sangraal Campaign and the Salvation Run - A hand-picked Imperial Fists assault force despatched from Terra launched a daring raid to capture the antidote to a slow-burning Exterminatus-class viral weapon deployed against the Loyalist holdfast of Gramercie on the contested Hive World of Herkaliaum. After recovering the antidote stocks from the Traitor Mechanicum Biologis gene-labs, the heavily outnumbered Imperial Fists fought their way through massed Traitor forces, running a deadly gantlet through the underhives of Herkaliaum to deliver the antidote to Loyalist medicae detachments, thus saving the population of the Gramercie sub-hive. Viral overspill ravages the Traitor forces now unable to contain or cure the contagion in their own ranks, and within solar weeks, Herkaliaum is liberated by the servants of the Emperor. The legend of the so-called "Salvation Run" becomes a rallying cry for Loyalist support in the sector, turning the Sangraal Campaign in the Loyalists' favour and cementing their hold on the loyalty of the Segmentum Solar.009.M31 Establishment of the Imperium Secundus - With the Imperium severed in two halves, isolated and ignorant of each other as a result of the raging tumult of the Ruinstorm, the light of the Astronomican is no longer visible from Ultramar and no word of the Emperor has been heard for several years. Ultramarines Primarch Roboute Guilliman declares the foundation of the "Imperium Secundus" as a means of continuing the fight against the Traitors and securing the Emperor's legacy. When the Blood Angels arrive at Ultramar having escaped the Signus Cluster, Guilliman proclaims his brother Sanguinius as the rightful heir to the Emperor as regent or "imperator regis" of the Imperium Secundus. Guilliman will later admit this was perhaps the worst mistake he ever made, and seek to bury all records of the Imperium Secundus' existence. [Extract sanctioned for data purge]009.M31 Battle of Sotha - The far-flung world of Sotha lay close to the edge of the galaxy's Eastern Fringe, almost at the limits of both the fiefdom of the Five Hundred Worlds of Ultramar and the span of all Imperial space. On this world the Ultramarines had discovered beneath its tallest peak, Mount Pharos, a massive aperture constructed by an unknown xenos species (identified millennia later as the Necrons). This device functioned both as a telepathic beacon and route-finder, and it also permitted instantaneous communication across unimaginable distances, even penetrating the raging tumult of the Ruinstorm. Following their defeat at the hands of the Dark Angels at Tsagualsa, remnants of the Night Lords Legion followed this beacon in the Warp, which guided them safely to the world of Sotha. Over many solar months, the Night Lords secretly gathered intelligence on the suspicious activities of the Ultramarines, and soon discovered the nature of the arcane device, also named the Pharos, upon the restricted planet. The Night Lords launched a surprise assault upon the lightly-garrisoned world, intent on seizing the Pharos in order to use it to determine the location of their flagship, the Nightfall, as well as the whereabouts of their missing Primarch Konrad Curze. In the ensuing battle, the Loyalist Iron Warriors Warsmith Barabas Dantioch sacrificed himself by overloading the Pharos and burning it out, so that the Night Lords would be unable to utilise the device's powerful abilities. What far-reaching consequences this would have for the galaxy would not come to pass for another ten standard millennia, for the massive final emission of psychic energy by the Pharos through the Warp penetrated the intergalactic void and served as a beacon one last time -- for the hive fleets of the Tyranids.ca. 009.M31 Vulkan Lives! - The Primarch Vulkan's charred remains are recovered by the Ultramarines from the surface of Macragge where his body fell after burning up in the atmosphere following his fall from orbit. The Ultramarines initially assumed the massive corpse was some kind of grotesque statue. But over the following solar days, Vulkan's body begins to regenerate as his abilities as a Perpetual assert themselves, and eventually life returns to it. Vulkan returned to life in a mentally unstable state, and was often violent and incoherent. This was due to the perverse bond that had formed between Vulkan and his disturbed brother Konrad Curze during the solar months when Vulkan had been continuously tortured by the Night Haunter while a prisoner aboard the Night Lords' flagship Nightfall. Vulkan often reacted violently as he could sense the presence of Curze nearby. Unknown to the Dark Angels, who had recently arrived on Macragge after the declaration of Imperium Secundus, Curze had actually accompanied them, taking refuge in the bowels of their flagship following the Night Lords' defeat at Tsagualsa. As the Night Haunter proceeded to cause as much murder and chaos as possible among the people of Macragge, Vulkan eventually broke his bonds and began hunting the Night Haunter. They battled across Macragge's capital city until they were confronted by Vulkan's fellow Perpetual John Grammaticus, who used the Fulgurite, a solidified fragment of the Emperor's psychic power, to stab Vulkan through the heart, seemingly killing him. This time, however, Vulkan did not recover from the wound. In the battle's aftermath, Curze escaped. Vulkan was placed in stasis within a stasis-sarcophagus, hand-crafted by Roboute Guilliman himself, with the words "Unbound Flame" engraved on its side.ca. 009.M31 Rebirth of Vulkan - Following the death of their primarch once more on Macragge, the Salamanders' Shattered Legion survivors of Isstvan V had also been drawn to the Ultramarines' homeworld through the Ruinstorm by the empathic beacon of the Pharos and were allowed to stand vigil over their fallen primarch's casket. Their surviving First Captain Artellus Numeon was convinced that Vulkan yet lived, and eventually took his primarch's body on an arduous expedition back to the Salamanders' homeworld of Nocturne. Numeon was certain that if Vulkan's body were lowered into the cleansing fire of the Unbound Flame of Mount Deathfire, he would be restored to life once again. The Salamanders vessel was pursued by a large Traitor fleet consisting of elements of both the Death Guard and the Word Bearers, whose commanders each had their own personal reasons for acquiring Vulkan's body. Miraculously, the Salamanders unexpectedly found their way through the turbulent Ruinstorm, and arrived at Nocturne, where they were greeted by Nomus Rhy'tan, the Lord Chaplain of the XVIIIth Legion and Keeper of the Keys of Prometheus. A battle ensued between the Traitor and Loyalist forces, in which the Salamanders eventually emerged victorious. Following this victory, the Salamanders conducted the burial rites of Vulkan, and returned their primarch's body to the fires of Mount Deathfire, in the hopes that Vulkan would be resurrected. After over a solar week of waiting, the uncertainty broke Numeon's spirit. As the next Time of Trials on Nocturne drew near, First Captain Numeon renounced his rank and position. He wandered away into the burning ash wastes around Mount Deathfire and offered himself as a final sacrifice so that his gene-father and primarch could be restored.053.009.M31 Carnage of Morox - In one of the largest confrontations between Loyalist and Traitor-aligned mortal auxilia and militia forces, in excess of three billion battlefield fatalities are recorded as the death toll unleashed by a grinding war of attrition on the sector capital world of Morox Excellus. The Morox Civil War takes place in almost total isolation from the rest of the galaxy owing to turbulent Warp Storm activity and the lack of any real strategic significance to either side of the wider conflict, and is noted for the exponentially increasing levels of atrocity and rapid technological regression of the conflict.010.M31 Drussen Atrocity - Rumours of the presence of a forbidden Empyreal engine draws the attention of splinter elements of both Traitor and Loyalist forces, leading to a brief war which ravages the isolated world of Drussen, the apocalpytic conflict halving the world's population in a single solar night.010.M31 Scouring of Gilden's Star - Scattered elements of the Blood Angels Legion fight a long and bloody campaign against Word Bearers forces near the galactic core on the borders of the Imperium Secundus that culminates in the near-total destruction of both armies. During the campaign, the Blood Angels prove merciless in scouring worlds which have embraced the daemonic teachings of the "Dark Apostles" of the Word Bearers, putting all seven colonised worlds of Gilden's Star to the sword in one particularly notable instance.010.M31 Battle of Nycron - Under the direction of Imperial Fists Primarch Rogal Dorn, a Loyalist battlegroup led by elements of the Salamanders Legion, and supported by thirty regiments of the Imperialis Auxilia and a strike force of Legio Astorum Titans, engage an Emperor's Children millennial assigned to garrison the Beta-Garmon System on the edge of the Segmentum Solar. The Emperor's Children contingent is surprised at Nycron City on Beta-Garmon II and after a hard-fought battle, the Emperor's Children forces along with their Legio Mortis allies at Beta-Garmon III are driven out, placing the system into Loyalist hands and triggering within the standard year the first of an escalating series of Traitor counterattacks with the goal of retaking Beta-Garmon as a stepping stone for an eventual attack on Terra. Ultimately, these will only serve as a prelude to the far greater conflict in the system to come known as the Battle of Beta-Garmon.010-013.M31 Grand Imperial Muster and the Battle of Beta-Garmon ("The Titandeath") - For reasons only understood later in the war, the Ruinstorm that had been summoned by the Primarch Lorgar's servants among the Word Bearers Legion several standard years before during the Battle of Calth began to abate across vast swathes of the galaxy, reopening astropathic communications and transport routes to Terra. Loyalist high commanders were able to utilise the potent astropathic relay located in the Beta-Garmon System to contact and recall formerly lost or stranded Imperial forces from across the wartorn reaches of the northern Imperium. The Imperial muster at Beta-Garmon rapidly escalated into the largest gathering of Loyalist might since the early years of the civil war, a concentration of force so mighty that the Traitors were forced to respond in kind. The resulting clash of arms, the Battle of Beta-Garmon, would also become known as the "Great Slaughter," a theatre of war of such scale that it would encompass the Titandeath and the Sea of Fire campaigns, each major battles in their own right. The conflict saw billions of lives lost, thousands of starships destroyed, and the might of the Collegia Titanica all but broken. By its end, both sides were so badly bled that their only remaining option for ultimate victory was to force a final, decisive confrontation. As history relates, that final battle would be fought at Terra, but only after the weighty butcher's bill of the Great Slaughter was paid in full...010-012.M31 Battle of Tallarn - Tallarn, an Imperial muster world of almost unparalleled size and importance, comes under direct attack by the Iron Warriors Legion after their emergence from the Eye of Terror in an attempt by Perturabo to retrieve a powerful Chaos artefact hidden beneath the planet's surface. Perturabo's Legion is bolstered by dozens of allied Traitor Imperial Army regiments, the Titans of the Legio Krytos ("God Breakers") and the Knights of House Caesarean. Both the Loyalist and the Traitor high commands are taken by surprise by Perturabo's actions and the invasion quickly escalated after he ordered an Exterminatus action upon the world, scouring its surface of living matter by way of a voracious Life-Eater viral barrage that rendered the surface of the once-verdant world of Tallarn poisoned slime and makes the air unbreathable. While the population is all but wiped out, many defenders survived thanks to the existence of extensive subterranean shelters. The ensuing campaign is fought between vast formations of Imperial Army and Solar Auxilia tanks, the Titans of the Legio Gryphonicus ("War Griffons"), the Knights of House Megron, the indentured automata of the house army of the Rogue Trader Sangrea as well as the armoured forces of the Iron Hands, Imperial Fists, White Scars and Ultramarines Legions. No infantry can survive in the poisoned wastes of Tallarn, and most of the vehicles that do fight have been environmentally-sealed. As the conflict grinds on, it draws in Loyalist and Traitor forces from hundreds of worlds across the entire Segmentum Tempestus before its cataclysmic conclusion and the subsequent retreat of the Traitor forces. The Battle of Tallarn is now considered the largest armoured engagement in the known history of Humanity, and while counted as a victory for the Loyalists, millions of warriors and war machines on both sides were left scattered across the lifeless, deadly surface of the planet. Tallarn will be reclassified in the wake of the battle as a Desert World.010-012.M31 Fate of the Sabalis Liberatus - The Sabalis Liberatus, a Raven Guard Legion battlecruiser lost in the Warp since escaping the void battle over Isstvan V, finally broke into realspace near Galaspar on the borders of the Veiled Region on the southern galactic fringe. The survivors on board, comprising a mixture of Astartes from different Loyalist Legions, had spent the time in self-imposed suspended animation and awoke to find themselves utterly cut off from information or support. Fired on by Imperial patrol vessels whose captains had sided with the Traitors, this "Shattered Legion" force boarded the patrol vessels and conquered their attackers. Effecting repairs from the captured voidships, they began a further two-standard-year odyssey of battle to return them to the Segmentum Solar and finally Terra, where they would ultimately fight in the void battles against the Traitor onslaught in the closing days of the great civil war.010.M31  Cataclysm of Iron Begins - Across the sectors of the Segmentum Tempestus and Segmentum Pacificus are located numerous Forge Worlds known collectively as the "Belt of Iron." Since the sundering of the Imperium, many of their number have declared for the Traitor and Dark Mechanicum causes at the engineering of the Fabricator-General Kelbor-Hal of Mars, while others remained loyal to Terra or in some cases sought to remain aloof from the conflict as much as possible. Strife and tentative conflict between these once-aligned worlds erupted finally into full-scale war in 010.M31 over the question of the Emperor's legitimacy as their Omnissiah. This pitched the Dark Mechanicum-aligned Forge Words of Incunabula, Urdesh, Valia-Maximal and Kalibrax against the forces of the Loyalist Forge Worlds Graia, Arl'yeth and Atar-Median, while Arachnis and Jerulas Station both fell into the anarchy of civil war. The resulting conflict, later known as the "Cataclysm of Iron," sees the forge lords, their armies and allied Titan Legions and Knight households turn on each other in protracted warfare, with scores of Human-inhabited worlds in the region suffering as they become the battlegrounds upon which the forge lords fight. Even the apocalyptic intervention of the Dark Angels cannot end the spiralling disaster, and battles between dozens of Forge Worlds continue long after the Horus Heresy has run its course.010.M31 Battle of Pluto - As part of the ongoing Solar War, the Alpha Legion carries out multiple diversionary attacks of sabotage and preparation as part of the broader Solar War, which plunges the Sol System into complete chaos. Their true target, however, is the fortress moon of Hydra, which orbits Pluto. First Captain Sigismund and a small fleet of Imperial Fists stubbornly defend Pluto against the larger Alpha Legion fleet until help arrives, in the form of the great mobile star fort Phalanx and a large fleet of Imperial Fists and Armada Imperialis warships. At the height of the battle, the Primarch Rogal Dorn, the Praetorian of Terra, led an assault on the fortress moon and confronted his brother Primarch Alpharius and engaged him in melee combat. Alpharius was slain by Dorn, and the Alpha Legion forces were forced to withdraw.011-013.M31 Lorin Alpha Campaign - The White Scars and Emperor's Children conduct a high-speed duel across the last critical space lines connecting Terra to the northern Imperium. The aftermath of the Battle of Beta-Garmon brings Dark Mechanicum forces and the Sons of Horus to the planet, turning the tide against the White Scars and ultimately ejecting the Loyalists from Lorin Alpha.011.M31 Malagant Conflict - While the surviving Loyalist enclaves have been apparently crippled by the Warmaster Horus' onslaught, those Death Guard elements assigned to the garrison of their Legion homeworld of Barbarus spearhead an assault into the southern reaches of the Imperium. The grim warriors of Barbarus made the vast industrial hives of Malagant their prime target, a world made valuable by the strategic worth of its manufactoria, and to crush the defiance of the surrounding sectors, many of whom looked to the determined Loyalist leaders of Malagant for leadership. Yet where the Death Guard had expected to crush the mortal Malagantine auxilia in short order, they found themselves mired in cunning ambushes and punishing counterattacks led by Legiones Astartes bearing the sable mark of the Raven Guard. Lacking the numbers to meet the Traitors head-on, the sons of Corvus Corax plied their deadly skills as skirmishers and assassins upon their erstwhile brothers; trapping them on a world they could not afford to abandon, battling a foe they could not pin down and crush. For three standard years, little more than a company of Raven Guard occupied an entire augmented Chapter of Barbarus' finest, until 014.M31 when the Death Guard retreated in the face of approaching Loyalist reinforcements from Inwit.011.M31 The Marches of Madness - The World Eaters made seemingly senseless raids on population centres across the Ultima Segmentum. Their brutal attacks are aimed at causing maximum Human casualties, ignoring both infrastructure and military targets. The attacks are accompanied by unseasonal violent storms and unnatural crimson cloud bursts, all indications of increased Empyreal activity wherever the World Eaters go. By this time in the Heresy, the World Eaters have come fully under the grip of Khorne and now seek only more blood for the Blood God's unending thirst, no longer even trying to pursue rational tactical or strategic objectives.011.M31 Second Battle of Paramar - Paramar V had fallen to the Warmaster Horus' hosts in the opening moves of the Horus Heresy. In response, a mixed force of Loyalists launched an assault against the strategically vital supply nexus with the intent of denying it to the Traitors' war effort. The Traitors numbered a substantial combined forces of Legio Fureans ("Tiger Eyes") and Legio Mortis ("Death's Heads") god-engines that were in the system re-arming and re-supplying after several standard years of intensive campaigning, and a large presence of Sons of Horus and Word Bearers Heretic Astartes. The Loyalists committed a large Titan force drawn from the Legio Atarus ("Firebrands"), Legio Ignatum ("Fire Wasps") and Legio Solaria ("Imperial Hunters"), with ground assault units of the Blood Angels and White Scars Legions. The Loyalists conducted a series of diversionary attacks across the Paramar System in order to draw Traitor forces away from their true target, before they conducted a full-scale planetstrike against Paramar V's primary spaceport, capturing it intact and then pressing outwards to begin the destruction of the mass-provender silos that sprawled across the plateau beyond. It was soon revealed, however, that the Traitors had seen through the Loyalist ploy and prepared a huge counter-attack force. Though the Loyalists inflicted heavy damage on the provender silos before the counter-attack hit home, the vast majority of the Loyalist invasion force was surrounded and destroyed without mercy.Battle of Ice World Tralsak (011.M31) - The shallow, frozen oceans of the Ice World of Tralsak were flash-boiled to steam by the fury of god-engine war as the Loyalist Titans of the Legio Atarus ("Firebrands") and the Legio Agravides ("Battle Scourges") clashed with the Traitors of the Legio Magna ("Flaming Skulls") and Legio Victorum ("Foe Slayers") as Loyalist Shattered Legions and Traitor World Eaters Astartes fought across the disintegrating landscape of ice floes. Ultimately, outright victory eluded both sides, and each used the cover of the world-enveloping fog thrown up by the destruction to extricate their forces and redeploy them elsewhere. Nevertheless, numerous supporting Knights of both sides remained to fight a war in which neither side conceded defeat.Tarren Suppression (011.M31) - The world of Tarren IV declared for the cause of Horus, its rulers having fallen for the honeyed words of the Warmaster's emmisaries. A Loyalist Retribution Fleet moved quickly to crush the treachery, and its forces occupied Tarren IV's capital city of Brandstat and stamped out anti-Imperial sentiment in a brutal mirror of the Traitors' so-called "Dark Compliance" of conquered worlds. The key to the suppression were the Titans of the Legio Defensor ("Nova Guard"), who bestrode the surface of Tarren IV, the mournful dirge of their war sirens demanding submission to the Emperor and making examples of those cities that refused to do so by blasting them into flaming ruins. As if to mock the expected order of things still further, later on, it was an allied force of the Emperor's Children Legion, the Legio Cybernetica and the Legio Mortis ("Death's Heads") that conducted a heavy planetary landing and "liberated" the world from the Loyalists during the campaign known to the people of Tarren IV as the "Relief of Brandstat."011.M31 Battle of Zepath - Obsessed with hunting down his brother the Night Haunter, the Primarch Lion El'Johnson eventually is able to trace a slim lead on his brother's whereabouts to the Zepath System, which had since fallen to the forces of the Word Bearers and World Eaters. Farith Redloss, the Lieutenant-elect of the Dark Angels' Hexagrammaton Dreadwing formation, was charged with leading the hunt for Konrad Curze upon the world of Zepath. The Dark Angels quickly uncovered the horrors perpetrated by the Word Bearers to fuel their dark Chaos rituals. Eventually, the Dark Angels took part in multiple engagements against the forces of both Traitor Legions, which culminated in the Zepathian capital city of Numentis. The Traitor forces were utterly annihilated by the victorious Dark Angels. The world was left in the care of its surviving population.011.M31 Scouring of the Nostramo Sector - In 017.M31, after the end of the Horus Heresy, a Retribution Fleet designated "Battlefleet Vengeance," led by the Blood Angels' 33rd Company, 9th Chapter, launched a campaign into the Nostramo Sector for further vengeance in their lost Primarch Sanguinius' name, against remaining active Night Lords combat units within the sector. Yet despite all intelligence to the contrary, no determined resistance was to be encountered by these fleets. Of the VIIIth Legion, only scattered and isolated warbands were discovered, and none larger than a reinforced company. They soon uncovered, on multiple, formerly Night Lords-held worlds, evidence that an unknown Blackshield force had ravaged the Nostramo Sector in 011.M31, leaving nothing but ruined fortresses and drifting battle-scarred wrecks of the VIIIth Legion in their wake. It wouldn't be until 017.M31 that this Blackshield force would be identified as the mysterious Ashen Claws.012-013.M31 Passage of the Angel of Death - Freed from their isolation by the abating Ruinstorm, the Dark Angels wreak havoc in a campaign of revenge against any loyal to Horus. A trail of blackened, scorched worlds is left in their wake across the southern Imperium, including the homeworlds of the Emperor's Children and Death Guard Legions, the Chaos-corrupted worlds of Chemos and Barbarus, respectively.012.M31 Balthor Sigma Intervention - A blood-maddened pursuit force of Traitor World Eaters Astartes engaged in hunter-killer operations against defeated Loyalist forces was counter-attacked by a Legio Osedax ("Cockatrices") demi-legio at the world of Balthor Sigma. The World Eaters are supported by numerous super-heavy tanks and therefore are able to hold the Cockatrices Titans at bay until, in quick succession, the Traitor tanks are engaged from an unexpected quarter and destroyed in short order. Entirely unheralded, a force of xenos Titan-analogues, later determined to belong to the Eldar, intervened to devastating effect. It was only when Traitor-aligned Titans of the Legio Fureans ("Tiger Eyes") fought their way through to reinforce the Traitors' lines that total defeat for the Warmaster's servants was averted. At the conclusion of the battle, the xenos Titans disengaged and vanished into the ash-shrouded depths of Balthor Sigma's equatorial magma wastes.012.M31 Birth of the Adeptus Mechanicus - A long-running political deadlock in the Council of Terra back on the Throneworld of the Imperium is finally broken, facilitating the formal establishment of the Imperial Adeptus Mechanicus. The Adeptus Mechanicus is recognised as officially separate and distinct from the corrupted Mechanicum of Mars. Fabricator-General Zagreus Kane is appointed its first High Lord of Terra to serve on the council. Final judgement is enacted upon the captive followers of the Traitor Fabricator-General Kelbor-Hal of the Dark Mechanicum, who are executed in their thousands. Immediately after, the union of Loyalist Titan Orders, under the umbrella of the Adeptus Titanicus or Collegia Titanica, is formed by the grand masters of several major Loyalist Titan Legions, although the future of other loyal former Mechanicum divisions such as the Legio Cybernetica and the regular military forces of each Forge World's Taghmata remains unclear.012.M31 Battle of Yarant - After an ill-counselled assassination attempt against the Warmaster Horus, the scattered Space Wolves are pursued to the Yarant System, where they make a desperate last stand. Leman Russ' many enemies press his Legion to near-extinction, and the Space Wolves are only saved by the unexpected intervention of Corvus Corax and the Raven Guard.012.M31 Scouring of the Ollanz Cluster - The Warmaster Horus' advance on Terra eventually reached the Ollanz Cluster, where he encountered Loyalist reinforcements bound for Beta-Garmon rearming and refuelling at the Borman System. The Loyalist fleet rapidly redeployed to oppose the Traitors' advance and to protect the valuable resource worlds of the stellar cluster. The turning point of the brief but intense conflict came at Borman IV, when a Legio Astorum ("Warp Runners") demi-legio launched a daring offensive towards the world's beleaguered capital city. The crucial Titan battle took place in the volcanic Yrevendi Desert immediately to the north of the capital, as Princeps Senioris Varr Harax led a surprise thrust through rough terrain at a weak point in the Legio Fureans ("Tiger Eyes") lines, accompanied by Astartes ground forces drawn from the Iron Hands Legion. The Tiger Eyes, having been drawn away by a bold diversionary attack, were annihilated by the Warp Runners, who were able to break through the Traitor Emperor's Children Legion's lines and reinforce the beleaguered planetary capital. Ultimately, Borman IV and the entire Ollanz Cluster were delivered from the Traitors' possession, which allowed the Loyalist forces to be redeployed to their original destination at Beta-Garmon.013.M31 A Return to Honour - Arcaes Odenathus, a Captain-Praetor of the Ultramarines' 10th Chapter, rallied the scattered survivors of his own brethren and those other Loyalists fighting across the Dominion of Storms in the galactic northeast and led them to the world of Honourum. Unexpected and unlooked for, this Loyalist assault struck the Word Bearers garrison on that world like a thunderbolt. Three solar weeks of desperate fighting ensued, and as all the Word Bearers' urgent requests for reinforcements were ignored by the Warmaster Horus, focused now on his final push toward Terra, the sons of Lorgar resorted to the most heinous of tactics to defend themselves. Daemons, Warp-tainted infiltrators and terrors of the wars of Old Night were unleashed, with both sides driven on past mortal endurance by their mutual hatred. When the last Traitor finally fell, there was nothing left of the grand cities of Honourum but blasted ruins; ruins whose very substance was so contaminated by the fell powers and terrible weapons they had unleashed that they would blight Honourum longer than the memory of the wars which spawned them.013-014.M31 Serpent's Coil - Despite the apparent death of their primarch at the Battle of Pluto, the Alpha Legion defy Horus' orders and set out to hinder Loyalists approaching Terra, seeking Ultramarines vessels in particular. Roboute Guilliman's fleet is forced to intervene to prevent further losses of vital reinforcements, critically delaying his arrival at Terra in time for the upcoming siege.014.M31 Siege of Terra (Battle of Terra) - The Siege of Terra, also called the Battle of Terra, was the final epic and cataclysmic campaign of the Horus Heresy. Many of the Loyalist Legiones Astartes had been waylaid by the forces of the Traitor Legions loyal to the Warmaster Horus and were unable to make their way towards Terra. The Imperial Fists had already returned to the cradle of Humanity and under the stern gaze of their Primarch Rogal Dorn, the Praetorian of Terra, had prepared the Throneworld's defences as best they could. Jaghatai Khan of the White Scars Legion had also managed to make his way to Terra with his Legion to help with the defence of the Imperial Palace. The Blood Angels Legion was able to make the Warp jump to Terra in time to meet the oncoming Traitor assault. Three entire Titan Legions of the ancient Mechanicum and close to 2 million mortal soldiers of the Imperialis Auxilia stood alongside the Loyalist Astartes to face the hosts of Chaos in a battle that would determine the fate of Mankind for the next ten millennia. Yet for all the might of the Emperor, for every effort of Sanguinius and the remaining Loyalist primarchs, the forces of Horus drove all before them. In too short a time, the Emperor of Mankind was assailed within His great palace on Terra. The Siege of Terra following the initial assault on the Imperial Palace lasted for fifty-five solar days. Both sides knew that victory or defeat for the Imperium of Man was at hand. Inexplicably, after the Traitors had penetrated into the Inner Palace, the Warmaster lowered his Void Shields aboard his flagship, the Vengeful Spirit in the final hours of the siege, and the Emperor rose to the challenge. With Sanguinius and Rogal Dorn at His side, along with a detachment of Legiones Astartes from both Legions, as well as the Emperor's personal guardians, the Legio Custodes, the Emperor teleported aboard the infamous Traitor flagship. Once the Loyalists were aboard, they were all separated before they rematerialised by the Warmaster's fell Warp powers and found themselves scattered throughout the massive warship. It was the Emperor who first arrived to the bloody scene in the Warmaster's throne room -- for the winged corpse of the angelic Sanguinius lay at Horus' feet. Father and son then fought one another in a titanic struggle, the fate of all Humanity hanging in the balance. In the end, the Emperor sorrowfully slew His once-beloved son and used the full strength of His immense psychic powers to eradicate Horus' soul from the Warp so that the Warmaster could not be resurrected by the Ruinous Powers he served. But the Emperor had been mortally wounded Himself during the vicious fighting. With their leader gone, the Traitor Legions were routed from Terra and chased by the vengeful Loyalist forces into the hellish realm of the Eye of Terror, while the Emperor was ultimately saved by the arrival of Rogal Dorn, who took his dying father back to the Imperial Palace. Upon the Emperor's final instructions, Dorn had Him placed into the confines of the life-sustaining mechanisms of the great arcane device known as the Golden Throne, and then He spoke no more. Humanity had prevailed, and the Imperium of Man would live to endure, but had paid a terrible price for its victory -- a price that would continue to be paid by the generations to come for the next 10 millennia.