Milky Way galaxy - Age of Man: For millions of standard years after the Necrons went into hibernation on their Tomb Worlds, the devastated sentient populations of the galaxy slowly recovered. In time, the Aeldari emerged as the most dominant civilisation in the galaxy, with the core of their star-spanning empire located in the region of what would later become the Eye of Terror Warp rift.But on the planet called Earth and later Terra by its inhabitants, a humanoid species known as Mankind was rising to prominence over 40,000 standard years ago. During the Age of Terra, or the Age of Progress as it is sometimes called by Imperial historitors, the Human race advanced beyond its ancient pre-industrial past to obtain spacefaring capability and began to slowly settle the habitable worlds in its own solar system and in the star systems near its homeworld using massive sublight starships. During the next era of Human history, the Dark Age of Technology, Mankind discovered how to manipulate the Warp to allow faster-than-light interstellar travel and psychic communications.With starships outfitted with Warp-Drives and Human Navigators, Mankind began to rapidly expand beyond its home region of the galaxy, competing with the powerful Eldar empire for new worlds and resources. This period saw the development of the Standard Template Construct (STC) database of advanced technologies that were used to colonise the galaxy.Eventually Humanity had settled on more than a million worlds, some habitable from the start for human life like Terra, others terraformed to make them livable. At its height in the Dark Age of Technology, humanity commanded technological prowess and scientific knowledge that has long been lost to the people of the present-day Imperium. In time, the scattered human worlds forged an interstellar federation to enhance their political and economic unity. This was the Golden Age for Mankind and this great civilisation persisted for long centuries.But human scientists, in their hubris, created the true artificial general intelligences later known in legend as the Men of Iron. Intended to serve humanity in both industry and war, the Men of Iron ultimately rebelled against the wishes of their human masters and unleashed a war across the galaxy to exterminate or enslave Humanity that fragmentary ancient records indicate may actually have been even more destructive to human space than the Horus Heresy.The ancient Human interstellar civilisation never recovered from the destruction of this conflict, though Mankind prevailed at great cost against its robotic children. Immediately after Humanity had defeated the Men of Iron, the plague of uncontrolled psykers first appeared on human worlds. But Mankind was not yet ready for the burdens of psychic power and many of the newly emergent human psykers lacked the strength of will to control their powers. Many were possessed by Daemons and other Warp entities and proceeded to cause immense damage to their already battered homeworlds until psykers were often killed on sight as "witches" on many Human planets.But the true death knell of Humanity's Golden Age was the coming Fall of the Aeldari. As the Aeldari Empire reached its zenith in the 24th Millennium and its people lost themselves in orgies of hedonistic excess, their collective psychic emanations roiled the Warp and gestated a hideous new presence within the Immaterium, the Chaos God Slaanesh, the Prince of Pleasure.Slaanesh's growth so roiled the Aethyric dimension that it spurred on the Human evolution towards becoming a fully psychic species like the Eldar, producing the plague of Human psykers. At the same time, Slaanesh's gestation disrupted the eddies and tides of the Warp, leading to the emergence of massive Warp Storms across the galaxy. These storms cut off all interstellar travel and communications between the worlds of Mankind, which were so dependent on the Immaterium for both faster-than-light travel and astropathic communications.Plagued by psykers and unable to communicate or trade with the other worlds of its commonwealth, Mankind's great interstellar civilisation simply collapsed. Its planets were thrown into a terrible new era of technological decline, constant warfare, religious superstition, disease and death.Many of the Human worlds of the galaxy were consumed by blood-letting and warfare as their economies collapsed with the end of interstellar trade and the lack of the goods that many populations had depended upon for survival. Whole worlds died as a new Dark Age claimed the whole of the Human-settled galaxy, and so this time is remembered as the Age of Strife by Imperial historians. It lasted for almost 5,000 Terran years of pain and terror.When Slaanesh was at last born in the 30th Millennium, the psychic birth pangs of the new Chaos God echoed through the Immaterium and into the material universe, ripping open the massive rift between the realities now known as the Eye of Terror. This hideous Warp rift swallowed most of the homeworlds of the Eldar empire, destroying them, while the souls of billions of Eldar were swallowed by the bloated mass of psychic energy that was Slaanesh.Only those Eldar on the craftworlds, the Maiden Worlds and within the labyrinthine corridors of the Webway were saved from the Prince of Pleasure's eternal hunger for Eldar souls. Yet the birth of Slaanesh also cleared the Warp of the continuous psychic emanations that had produced the constant Warp Storms in the material universe and had made interstellar travel and communications impossible.On Terra, ravaged by millennia of competition and warfare between the tribes of techno-barbarians who had fought for control over the course of the Age of Strife, the future Emperor of Mankind finally ended His ancient habit of working anonymously over the millennia through a variety of different personas to better the Human race. Realising that in its current straits Humanity would never again be able to rise to its former greatness without the help He could provide, the Emperor revealed His full strength and power to the people of Terra and launched a great conflict known as the Unification War at the end of the 30th Millennium to unite all of Terra beneath His rule.Using advanced genetic engineering techniques to create an army of super-soldiers clad in power armour, the Emperor faced off against the techno-barbarians and defeated their armies one by one, forging them into a unified planetary government under His rule. With Terra united once more under an autocratic Imperial government, the Emperor next forged an alliance with the Mechanicus of Mars to provide him with the starships and technology He would need to reunite all the scattered worlds of Mankind into a single government under His own enlightened rule, a new Imperium of Man.The Emperor intended to spread civilisation and progress once more across the battered planets of Humanity's realm now that the Age of Strife was ending and to replace the millennia of superstition and ignorance with the new cult of scientific rationalism and respect for Human progress that he called the Imperial Truth. The Emperor hoped that the replacement of Mankind's old beliefs in magic and religion with the cold rationalism of science would strike a deep blow against the Ruinous Powers of Chaos and weaken their growing influence over both humanity and the galaxy at large.To carry out His intentions, the Emperor needed military leaders of surpassing genius and physical might, men much like Himself since He could not be in every place at once. From His own unique genetic material He created 20 genetically-engineered Human males of unsurpassed beauty, size, strength and intellect, the Primarchs who would lead His armies of altered soldiers in conquest across the universe.But the Chaos Gods were not unaware of the Emperor's plans to strengthen the forces of Order across the galaxy and so they moved first, opening a Warp rift in the middle of the Emperor's own gene-lab, beneath the Himalazian (Himalayan) Mountains on Terra, and teleporting the infant Primarchs, still in their gestation capsules, to various worlds across the galaxy. Unfortunately, many of them were tainted with the mark of Chaos in the process.Yet the Emperor was nothing if not resourceful. Using samples of genetic material that had been taken from the developing Primarchs, the Emperor created a new race of transhuman warriors, the 20 Legiones Astartes or Space Marine Legions, who would take the lead in the great expedition to reunify Mankind beneath the Aquila of the new Imperium. Dividing the Legions up into hundreds of different Expeditionary Fleets assisted by the forces of the Mechanicus of Mars, the Emperor initiated the Great Crusade to expand the Imperium of Man and spread its Imperial Truth across the galaxy.In time, some 200 standard years after the start of the Great Crusade in the early 31st Millennium, the Imperium had spread its sheltering wings across hundreds of thousands of Human worlds, restoring a measure of civilisation and progress to the scattered peoples of Mankind and inaugurating a new age in Human history, the Age of the Imperium, our current era. In the course of the Great Crusade, the Emperor had rediscovered His scattered primarch sons, and placed each of them in command of the Space Marine Legion that had been created from their gene-seed. In particular, the Emperor placed His greatest trust in Horus, the mightiest and most gifted of all the primarchs, the man in whose hands the Emperor ultimately entrusted the entirety of the Great Crusade when he returned to Terra to carry out his next project in pursuit of a new Human Golden Age -- opening up the Aeldari Webway for use by the Imperium.But the taint of Chaos ran deep in some of the Primarchs. Horus, whose pride proved to be as large as his talents, was seduced to the side of Chaos through the machinations and lies of the Chaos Gods. Horus eventually convinced eight of his brother Primarchs and their Space Marine Legions to join him and turn Traitor to the Emperor. These Traitor Legions and their accompanying units of the Imperial Army and the Mechanicum unleashed the horrendous interstellar civil war that is remembered only as the Horus Heresy.For seven standard years they made war upon the Loyalist forces, killing billions as they drove towards the heart of the Imperium in Horus' determination to overthrow his father and replace him as the Master of Mankind. In the end, the Traitor forces assaulted the great fortress of the Imperial Palace during the Battle of Terra, forcing the Emperor Himself to take up arms to defeat his wayward son.On the bridge of Horus' Battle-Barge the Vengeful Spirit, the Emperor ended His son's life, and saved Humanity from the unending nightmare of Chaos, but at a high price. The Emperor suffered a mortal wound and was placed within the Golden Throne, an ancient technological device of unknown origins that kept His ravaged body in stasis while still allowing His mind to roam free in the Warp, providing the psychic beacon of the Astronomican that tied the Imperium together while He combatted the whims of the Ruinous Powers.In time, the Imperial Truth was replaced by a new faith in the God-Emperor of Mankind; the religious superstition the Emperor had hoped to replace instead became the foundation of a far more effective shield against the ravages of Chaos vested in the simplest mantra of the new Imperial Creed: the Emperor protects.In the 10,000 Terran years since the end of the Horus Heresy, the Imperium has continued to expand across the galaxy. Despite the terrible threats presented by Heretics, mutants, xenos and the Forces of Chaos, Humanity has managed to remain the dominant species of the Milky Way Galaxy.Yet the political repression and outright acts of tyranny required to maintain Human control over this vast domain have only worsened over the long centuries while Human technological levels have continued to decline from what they were at the time of the Great Crusade.And now, in the late 41st Millennium, the Imperium faces its greatest challenge since the Horus Heresy. The Forces of Chaos, led by Horus' successor and former lieutenant, Abaddon the Despoiler, broke through the cordon erected by Imperial forces over the Fortress World of Cadia, at last destroying that great bastion of Imperial defence.Reality itself has fractured, splitting the galaxy in half with the birth of the Great Rift. Countless Daemons and warbands of Heretic Astartes now spill from that great wound in reality to assault the worlds of Mankind.The Hive Fleets of the Tyranids are spreading like a plague of xenos locusts from the Eastern Fringes of the galaxy, intent on reaching the source of the Astronomican on Terra. Heresy and rebellion spread across the Imperium as never before.The Necrons and their enslaved former C'tan masters, having slumbered for untold millions of years, are at last beginning to awaken across the galaxy, to begin their reconquest of their lost empire.In the halls of the Imperial Palace, new whispers have begun to gather, rumours which murmur that the Golden Throne has begun to fail and the Adeptus Mechanicus lacks the knowledge to repair it...