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"The martyr's grave is the keystone of the Imperium."

— The Liber Imperialis

The Imperium of Man, also called simply the Imperium, is a galaxy-spanning, interstellar Human empire, the ultimate authority for the majority of the Human species in the Milky Way Galaxy in the 41st Millennium A.D. It is ruled by the living god who is known as the Emperor of Mankind.

However, there are other humanoid species classified as Imperial citizens, mainly mutant offshoots of genetic base-line Humans who are known as Abhumans and include such Human sub-species as the Ogryns, Ratlings and Squats.

The founder and ruler of the Imperium is the god-like Emperor of Mankind, the most powerful Human psyker ever born. The Emperor founded the Imperium over 10,000 Terran years ago in the late 30th Millennium during the Unification Wars on Old Earth following the apocalyptic period in Human history known as the Age of Strife.

The Emperor continues, at least nominally, to rule the Imperium as both its political master and its primary religious figure. However, His badly damaged body was interred within the cybernetic life support mechanisms of the arcane device known as the Golden Throne following His mortal wounding during the ancient interstellar civil war of the Horus Heresy.

Because of this terrible fate, the Emperor is incapable of interacting with others on a day-to-day basis and has left the basic governance of His Imperium to the Senatorum Imperialis, an oligarchic ruling council of the most powerful noble lords and adepts in the galaxy. The Senatorum Imperialis is currently led by the Emperor's genetic son, Primarch Roboute Guilliman, who chairs the council and directs Imperial policy as the lord commander of the Imperium and Imperial Regent.

The Imperium of Man is a war-torn stellar empire, teetering on the brink of collapse. For 10,000 Terran years it has been ruled by the deathless Emperor, a being of almost limitless psychic power, to whom thousands of souls are sacrificed daily to provide Him the psychic strength to maintain the Imperium's lines of communication and transport.

The peoples of the Imperium live in a galaxy where Daemons are real, mutation is frequent and death is a constant companion. To be alive in the 41st Millennium is to know that the universe is a terrifying and hostile place. It is a place where you are but one amongst billions and, no matter how heroic your death, you will not be missed.

A truly vast domain, the Imperium is spread amongst the many stars of the galaxy. Its territories encompass untold millions of stars and countless more Human lives.

In its name, terrible wars are fought and desperate sacrifices made, yet even this river of carnage and blood is a small price to pay, for the Imperium is the guardian of Humanity. Were it to pass into nothingness, so too would the Human species, destroyed by enemies uncountable, to the braying laughter of the Dark Gods.

The Imperium is the largest and currently most powerful political entity in the galaxy, consisting of at least 1,000,000 Human-settled worlds dispersed across most of the Milky Way Galaxy. Consequently, an Imperial planet might be separated from its closest neighbour by hundreds or even thousands of light years.

As a stellar empire, the size of the Imperium cannot be measured in terms of contiguous territory, but only in the number of planetary systems under its control. However, most Humans in the galaxy have little day-to-day contact with the government of the Imperium unless they serve in one of its adepta or run afoul of its various protectors, such as the Inquisition or the Adeptus Arbites.

The Imperium is primarily an interstellar tribute empire, allowing its member worlds to largely govern themselves as long as they recognise the authority of the Emperor and His servants and support the state religion, the Imperial Cult, which holds the Emperor to be the one, true god of Mankind.

Every world of the Imperium must also pay the Imperial taxes levied on them in the form of troops and materiel that is known as the Imperial Tithe. These resources go to the service of the Astra Militarum and the Navis Imperialis, the armed forces which keep the Imperium united and safe.

The Imperial Tithe supports the overall economy of the Imperium by redistributing resources where needed, usually to shore up one region of the Imperium where conflict is raging by drawing resources from more peaceful sectors.

In general, the Imperium promotes the development of a neo-feudal political system, which the High Lords of Terra and the Inquisition have long believed to be the most stable form of Human government. There are few Human-settled worlds in the galaxy where any but the most wealthy nobles have any say in the government of their planet, and the Imperial establishment generally characterises any movements toward "democracy," self-rule or the overthrow of the neo-feudal system as outright heresy against the divine plan of the God-Emperor.

This intense need for political stability and the growing military demands upon the Imperial system presented by the myriad and growing threats of the 41st Millennium have created a repressive and stagnant galactic government. In the present Imperium, science and Human progress have essentially been halted in service to the need to simply maintain the crumbling status quo. It is not for nothing that many Imperial scholars consider the current age the "Time of Ending" for Mankind.

Several alien species and dark mystical forces -- Chaos, the Tyranids, the Craftworld Aeldari, the Drukhari, the Orks, the T'au, and the undying Necrons -- now challenge the supremacy of the Imperium and Humanity's predominant place in the galaxy. From within its own creaking and increasingly stagnant and repressive edifice, the Imperium is threatened more insidiously by rebellion, mutation, dangerous psykers and subversive Chaos Cults.

However, despite its myriad problems, without the admittedly authoritarian and often harsh protection of the Imperium, Mankind as a whole would have fallen prey to the countless perils that threaten it. Without the Imperium of Man and Mankind's faith in the Emperor who guides it, the Human race would have become extinct long ago.


"Why do I still live? What more do you want from me? I gave everything I had to you, to them. Look what they've made of our dream. This bloated, rotting carcass of an empire is driven not by reason and hope but by fear, hate and ignorance. Better that we had all burned in the fires of Horus' ambition than live to see this."

—Roboute Guilliman, primarch of the Ultramarines, reflecting upon the state of the Imperium of the 41st Millennium and his devotion to the Emperor of Mankind
Palatine Aquila

The Palatine Aquila, ancient symbol of the burgeoning Imperium.

The road the Human species has walked through history stretches long and bloody at their collective heels. Its origins are hidden by the swirling dust of aeons, its present wreathed in the flames of war and ahead the future yawns like a dark and forbidding pit.

Still, Imperial historitors do what they can to preserve the truth of Humanity's journey, even if none may survive to read it.

Beneath the Imperial Palace complex on Terra lie thousands of kilometres of catacombs, hushed vaults and scroll-stuffed libraries. They are protected by rune-sealed bulkheads so formidable they could endure sustained orbital bombardment.

Their guardians are shadowy terrors, unsleeping, ever vigilant. So vast is their sprawl that predatory things have evolved amidst the shadows and the dust, ruling over trammelled ecosystems of pallid troglodyte vermin.

The knowledge kept here under lock and key spans the great ages of Humanity. Even this ultimate repository is mouldering and much eroded by entropy's inescapable touch, yet just those fragmented records that remain would take many lifetimes to study, and contain secrets enough to blast the reader's sanity or bring the entire Imperium crashing down.

It is well, perhaps, that few even know of the endless archives' existence. Fewer still are permitted beyond their doors.

The Imperium of Man was founded by the Emperor of Mankind, also called "The God-Emperor" and the "Master of Mankind", at the end of the Age of Strife, in the 30th Millennium AD. The Emperor, an immortal being born around the year 8,000 BC in central Anatolia on Old Earth, was the collective reincarnation of all the Human shamans who possessed true psychic abilities during the Paleolithic and Neolithic Ages.

Imbued with their combined psychic, physical and intellectual power, the Emperor was born an immortal being, a Perpetual, of unparalleled physical strength, psychic ability, charisma and intellect. The Emperor helped Humanity as a whole survive and prosper through the long millennia.

In various eras of Human history He intervened through various personas, some of them well-known historical personages, to guide Mankind, though such interventions were always brief and shrouded in legend and historical mystery.


An alternative form of the Aquila representing the Imperium of Man.

At the end of the Age of Strife in the 29th Millennium, the man who would become the Emperor finally took a direct, public, and permanent role in shaping the future of Humanity, believing that the damage done to the Human species by 5,000 years of terror, isolation and violence could not be reversed unless He openly guided Humanity as its leader.

As such, He shed all His prior identities and simply revealed Himself in the late 29th Millennium on Terra as the "the Emperor," determined to unite the entire species under His stern but benevolent rule. He intended to replace superstition, fear, poverty and intolerance with reason, science, progress and hope.

Age of Terra, M1-M15

No record now remains of Humanity's first, faltering steps into the interstellar void during the period remembered as the Age of Terra. Yet step they did, their confidence and skill increasing until steps became strides, became bounding leaps through space.

Ancient Earth became the shining hub of a powerful interstellar Human realm with Mars, the first world terraformed by Humanity, standing proud as a bastion of technological innovation and scientific learning.

Humanity's first encounters with alien races are not directly detailed, though fragments suggest that accords were struck with some, while wars were fought against others, most notably the ever-belligerent Orks.

Little more can be said of this long-lost age of adventure and hope. Glimpses and echoes are all that survive.

Age of Technology, M15-M25

The first indications of Human Warp travel date from the early millennia of this age, in ca. M15. They hint at gruesome disasters and many setbacks, yet it is clear that eventually the faster-than-light Warp-Drive technology was perfected. The cultivation of the Navigator gene -- and the establishment of the Navigator Houses -- came soon after, allowing vast leaps in interstellar travel and the establishment of a full-blown Human empire amongst the stars.

As Humanity's power and influence grew, so too did its hubris. The indomitable spirit of Human endeavour has ever riser to the sternest challenges; interstellar exploration, trade and -- inevitably -- warfare presented challenges like nothing Mankind had faced before. Planetary colonisation proceeded at a ferocious rate.

It seems likely that, during this era, the Human race splintered and reformed time and again into warring or competing power blocs and planetary empires, but nothing could destabilise Human space as a whole.

Human scientists, engineers, inventors and innovators became the new gods. They worked alien technologies into their species' devices to increase their efficacy with little thought to the risks. They modified their species' genome to ever greater degrees, fashioning vast armies of tailored gene-troopers whose Humanity was all but lost amidst the array of freakish alterations worked upon their bodies and minds.

They invented Standard Template Construct machines -- or STCs -- that allowed Human colonists to rapidly fashion everything they needed to dominate new worlds from whatever natural resources were available. They developed sentient nano-plagues, world-sundering directed energy weapons and endless ranks of fearsome artificially intelligent Men of Iron that could be unleashed upon those who refused to bend to their wills, alien and Human alike. They fashioned thinking machines of vast intellect that administered to the every need of colony worlds transformed into glittering utopian paradises.

It was during this age, also, that Humanity's psychic evolution is said to have accelerated apace and therein lay the seeds of this first Human empire's annihilation. Arch-historitors, chronopedants and Inquisitors of the Ordo Hereticus have combed what scraps of information exist from this era and have agreed upon two things; first, that it is impossible now to separate fact from fiction, and second, that the first mentions of Human psykers appear around the end of M22, are near ubiquitous across Humanity's worlds by late M23, and that absolute anarchy is said to have engulfed the worlds of Mankind soon after.

The collapse was sudden and appalling, a wave of apocalyptic catastrophe that swept across Human space. Terrible wars saw entire star systems scoured of life. Armies of mechanical soldiers marched against their creators and slaughtered billions. The scourge of mutation ran rampant and everywhere psychic atrocities were unleashed, everything from psykers claiming godhood over entire worlds to daemonic possession and full-blown reality collapse as the Warp breached the dimensional barrier and invaded realspace.

Then came the most ferocious Warp Storms that had been seen in all of Mankind's history, cutting off all interstellar travel, trade and communication. Collapse followed swftly.

Age of Strife, M25-M30

The Age of Strife, also sometimes remembered as "Old Night," was a 5,000-year-long period of anarchy, war, and destructive technological regression from the 25th to the 30th Millennia that brought Mankind to the brink of extinction -- and reversed the highly advanced scientific and technological discoveries made by the interstellar Human civilisation of the Age of Technology that had preceded it.

The Age of Strife was caused by the negative psychic and physical effects of the vicious Warp Storms that ravaged large portions of the galaxy beginning in the 23rd or 25th Millennium, depending on the source, which were the "ripples" in realspace of the psychic gestation of the new Chaos God Slaanesh in the Immaterium.

If the previous age had been one of prosperity and enlightenment, the Age of Strife was its dark mirror.

It is hard for historitors of the 41st Millennium to separate fact from insane ramblings or prophecies of doom, but it appears that terrible wars taged across the length and breadth of Humanity's galactic domain. Many worlds were consumed entirely, while even those whose populations endured were cut off from one another by the Warp Storms ravaging realspace.

During this era of isolation and hardship, many Human colonies underwent drastic and widespread mutation. Some were destroyed by it, for those mutations were the result-of Warp energies saturating their flesh and engulfing their worlds.

Others underwent more natural processes of adaptation and evolution, transforming into into Abhumans such as Ogryns, Ratlings, Stiltlimbs or Beastmen. Many wondrous advancements were lost or fell into disrepair, most of the STC technologies amongst them.

During the Age of Strife, Slaanesh was forming within the Warp as a result of the growing hedonism and utter excess of the ancient Aeldari Empire in the millennia before its Fall.

One result of the Warp Storms produced by this long gestation was the impossibility of faster-than-light travel or astro-telepathic interstellar communication through the ravaged currents of the Warp, which led to the subsequent isolation of Human colony worlds and star systems separated by multi-light-year distances.

Human civilisation in the colonised portions of the galaxy fragmented, and where it survived, it took on wildly different forms. On Old Earth, the planetary economy collapsed with the loss of interstellar trade and communication with the rest of Humanity even as the social order broke down.

Subjected to Terran millennia of isolation, hardship, invasion and horror, countless worlds plunged into post-apocalyptic barbarism. Amongst them was Old Earth itself.

Wars, rebellion, and the diseases that inevitably followed in their wake were rampant. Vast swathes of the advanced scientific and technical knowledge accumulated in the previous millennia was lost or forgotten, and a slow descent into pre-industrial barbarism seemed inevitable for Earth and many of its colonies.

On the Human homeworld, brutal warlords emerged from amidst the strife and disorder who carved out new kingdoms to serve as their fiefdoms. The emergence of these often brutal neo-feudal kingdoms, the new nation-states of the people later termed "techno-barbarians" by Imperial historitors, imposed an uneasy peace on the Earth that was frequently interrupted by feudal conflicts.

The Human species seemed on the brink of extinction by the end of the 29th Millennium. And then, in Humanity's darkest hour, came the man who would become known as the Emperor of Mankind.

Great Crusade, M30-M31

Raptor Imperialis Icon

The Raptor Imperialis, early iconography of the Imperium of Man, utilised by the Thunder Warriors and newly-raised Space Marine Legions during the Unification Wars as well as veteran Solar Auxilia units.

Legend tells how at the end of the Age of Strife the Human homeworld writhed in the grip of terrible wars beyond count before the Emperor came. Techno-barbarians battled collectives of gene-soldiers through the blazing ruins of once-great arcologies. Cannibal savages unleashed unholy psychic powers upon legions of cyborg zealots.

Grand warlords, demagogues and psyker proto-deities rose and fell, each one threatening to finally take the planet and its people with them into damnation.

Yet the man who would become known as the Emperor sensed that the Warp Storms that had marked the Age of Strife were starting to subside, and that this offered an opportunity for Humanity to reunite in pursuit of a new Golden Age. The Emperor first emerged from His secret fortress beneath the Himalazian (Himalayan) Mountains in the late 29th Millennium.

He sought to unify all the techno-barbarian states of ancient Terra under His rule through either diplomacy or the waging of the brutal military campaigns later called the Unification Wars against the techno-barbarians tribes that ruled vast swathes of the Earth's blighted surface.

These wars were waged with superhuman soldiers later known as the Thunder Warriors who had been genetically-engineered by the Emperor's genius from his early followers to be faster and stronger than base-line Humans. Such warriors would provide the early foundation from which He would later decide to create the Space Marines.

After conquering the last of the independent techno-barbarian states of Old Earth, the Emperor began to lay the foundations of His burgeoning Imperium. At last, the Age of Strife was over. Hope was restored. Yet hope has ever been Humanity's addiction and curse both...

Understanding that no one man, even one such as He, could rule alone, the Emperor formed His War Council, comprised of His most able generals and a number of high-ranking administrators, the most formidable of whom was Malcador the Sigillite.

Malcador was not a warrior, but a man of learning with the bearing of a priest. His origins were unknown to all save perhaps the Emperor Himself, to whom some believed Malcador was distantly related.

Malcador was appointed to administer the newly-constructed Imperial Palace and Court in the Himalazian Mountains, and through this appointment also governed newly conquered Terra as his master's left hand. Where Terra had been a place of unending war it now became a place of unceasing activity, production and planning.

Just as the conquest of Old Earth was complete a mighty and unforeseen cosmic event occurred. A massive shock wave blasted across the Immaterium, clearing the Warp Storms that had plunged the galaxy into tumult and raged for more than five thousand standard years.

It seemed to some to be divine providence, fuelling the beliefs of those that considered the Emperor to be Himself divine (no matter how much He decried this claim). The way to the galaxy was now open and the Emperor's armies would be able to take to the stars, with the other planets of Terra's solar system the first step upon that road.

After conquering the last of the independent techno-barbarian states of the renamed world of Terra, the Emperor secured the allegiance of the techno-mystic Cult Mechanicus of Mars who controlled the most advanced remaining industrial fabrication and scientific research facilities in the Human-settled galaxy.

The Emperor promised in the Treaty of Mars to protect the Tech-priests' religion and respect the sovereignty of the Mechanicum and the autonomy of their Forge Worlds across the galaxy, affording them a level of independence unequalled within the Imperium. Furthermore the Emperor gave to the service of the Mechanicum six of the Houses of Navigators, so that their ships might once again travel safely through the Warp after the loss of their own thrall-Navigators centuries before.

The powerful Fabricator-General of Mars was given a seat on the War Council of the Great Crusade. With access to the giant manufactoria of Mars, this enabled the Emperor to vastly increase the power of his Legions with improved wargear and supply.

In addition, the Tech-priests of Mars lent their arts to the construction of the massive Warp-capable Battleships that could transport the Emperor's Legions across the galaxy, and provided the mighty city-crushing war machines known as the Titans to the ever-expanding Imperial military.

The Treaty of Mars married the Terran military might of the Emperor with the industrial strength of Mars and the Mechanicum. Now possessed of the needed manpower and materiel to make His dream a reality, the Emperor mobilised the resources of Terra and Mars to launch a vast new military campaign intended to reunite the whole of Mankind, dispersed across the galaxy, under His rule.

This campaign, the Great Crusade, marked the founding era of the period that would later be known as the Age of the Imperium. A vast fleet of starships was built in orbit of Mars, with which the Emperor's armies set out to reconquer the galaxy for Mankind.

But even before He had begun His campaign to reunite Old Earth, the Emperor had used His highly advanced knowledge of genetic engineering and the psychic arts to create the primarchs, 20 superhuman military commanders possessed of preternatural physical, mental and social attributes who had been created through the fusion of variations of His own genetic material with the power of the Warp.

The Emperor had known that the greatest foe of His plans to reunite Humanity and bring order to the galaxy would be the Ruinous Powers of Chaos and their daemonic servants. He had sought to protect His gestating primarchs from the Dark Gods while they grew in their gestation capsules in the Emperor's secret laboratories deep beneath the Himalazian Mountains, but the Chaos Gods saw through all His wards and protections.

They opened a Warp portal in the Emperor's own laboratory and stole the infant primarchs away from Terra, scattering them across the galaxy and tainting many of them with the power of Chaos.

Undeterred by this tragedy, the Emperor utilised what remained of the primarchs' genetic material. He had first crafted the Thunder Warriors to unite Old Earth. He then proceeded in the last days of the Unification Wars to transform ordinary Terran men into a new corps of transhuman warriors who would lead Mankind back out into the stellar void.

These men were the Emperor's Space Marines, the Legiones Astartes, superhuman warriors who knew no fear. Thanks to influxes of technology and resources from around the Sol System the Space Marine Legions were soon growing in numbers and capability at an exponential rate. The Space Marine Legions were to be the spearhead of the Emperor's attempt to reunite Mankind -- the Great Crusade's killing edge against which the strength of a foe would be broken and which would topple empires, Human or alien, by ripping out their hearts.

With Mars now part of the Imperium, the Great Crusade began in earnest and the rest of the Sol System was the first region of space to be conquered by the Emperor and His newly rearmed and re-equipped Space Marine Legions. The Legiones Astartes secured the scientific research installations and spacedocks of Luna which had once been controlled by the Selenar gene-wrights.

Broken and humbled, the enslaved gene-wrights of Luna would help forge the next generation of Space Marines who would carry out Mankind's conquest of the stars. Alien invaders were flushed from the moons of Saturn and Jupiter and their wretched enslaved Human inhabitants repatriated to Earth, the once-Human creatures of the Neptunian Deeps were exterminated without mercy, and the baleful false-world of Sedna at Sol's edge-light was boiled away to vapour under the guns of the new-forged Imperial war fleet. The next step was beyond.

The Great Crusade was a mammoth operation on an inconceivable scale and complexity that involved billions of troops and tens of thousands of voidships, and it is perhaps true that only a mind such as the Emperor's could have had a hope of successfully comprehending and executing it.

In order to manifest this conquest the Imperium's forces were divided up into an expanding and frequently reconfigured series of Imperial expeditionary fleets -- semi-autonomous battle groups assigned to voyage the stars and make war in the Emperor's name.

They were composed in chief of a bewildering array of voidships great and small. The paths of these fleets were dictated both in general by the Emperor and His War Council, but also by the will of their commanders who were entrusted to seek out the enslaved and destroy the alien under their own sway.

Imperium Dominatus Ancient Map3

Ancient Departmento Cartigraphicae Map of the Imperium Dominatus which displays the extent of the Imperial demesne in the final year of the Great Crusade, ca. 892.005.M31.

During the 200 standard years that the Great Crusade spread the Imperium across the galaxy, the Emperor slowly made contact once more with all of His scattered gene-sons, the primarchs, and to each He gave command of the Space Marine Legion that had been created from that primarch's genome.

Horus was the first of the primarchs to be rediscovered, on the barren Mining World of Cthonia only a few light years from Terra itself. Horus campaigned with the Emperor for 30 Terran years before the next of the primarchs was recovered, and during that time the two developed a special bond, the deep affection between a father and His favoured son.

The Astartes Legions, combined with the might of the Imperial Army (which was later separated into the Astra Militarum and the Imperial Navy after the Horus Heresy), reunited thousands upon thousands of Human-settled worlds into one interstellar civilisation, in the name, and under the rule of, the Emperor and the Imperium of Man.

But the Great Crusade was ended abruptly by the corruption and treachery of the Imperial Warmaster Horus, who was both the primarch of the Sons of Horus Legion and the overall military commander of the Great Crusade in its last days. This was an honour that had been granted to him by the Emperor, who had sought to leave the campaign so that He might return to Terra and oversee a highly-secret project intended to open up the Aeldari Webway to Human use.

But Horus and many of the other primarchs deeply resented the Emperor's absence from the Great Crusade and were even more disturbed by His attempts to replace the direct rule of the Imperium by the Emperor and His Primarchs with a bureaucracy of normal Humans.

Having established the Council of Terra, the new governing body of the Imperium to carry out the day-to-day work of ruling tens of thousands of worlds and trillions of Human beings, the Emperor took refuge in His vast laboratories and workshops beneath the Imperial Palace.

He began work in earnest on his new project to secretly extend the Webway to Terra, an enterprise that the Emperor hoped would be His greatest gift to Humanity. While the Emperor was locked away in His subterranean factories, trouble was brewing.

The formation of the Council of Terra proved to be a contentious decision with the distant primarchs, who were appalled when news of the formation of the council finally reached them on the frontiers of the Great Crusade. Some of the primarchs took great exception to being ruled by those mortals that they deemed less worthy and capable of such an honour than themselves.

The less stable primarchs felt that this was a betrayal of all they had fought and won in the Emperor's name and that their victories now counted for nothing. They, and many of their Astartes, felt that it was they who had suffered and sacrificed the most to build the Imperium and thus it was they who should have the greatest say in how it was ruled, not a council composed of effete Terran nobles and faceless mortal bureaucrats. This was one of many growing resentments that allowed the Ruinous Powers to infect and corrupt several of the Primarchs.

Riven by jealousy and ambition, Horus proved to be easy prey for the temptations of the Chaos Gods and the machinations of his own brother Lorgar, the primarch of the Word Bearers Legion, who had come into the secret service of Chaos during the course of the Great Crusade.

Given the opportunity, the Dark Gods falsely convinced the arrogant Warmaster that the Emperor had intended all along to simply use the primarchs and the rest of Humanity to transform Himself into a god. Enraged and offended at this notion, the Ruinous Powers then promised Horus their support in his bid to seize the Imperium for himself.

Horus ultimately convinced 9 other primarchs and their Space Marine Legions to join his cause and serve the designs of Chaos. He instigated the terrible Horus Heresy -- a galaxy-wide rebellion against the Emperor -- and eventually one-half of the Imperium's vast military forces, as well as elements of the Mechanicum, rallied to the Traitors' cause, unleashing the greatest conflict Mankind had ever known upon an unsuspecting galaxy.

Horus Heresy, M31

The Horus Heresy was fought across the galaxy for more than nine Terran years, beginning in ca. 005.M31 with the terrible Istvaan III Atrocity where Horus cleansed four of the Traitor Legions under his command of their remaining Loyalist elements and the Drop Site Massacre of Istvaan V, where Horus and his Traitor Legions nearly decimated three entire Loyalist Space Marine Legions through the most base of treacheries.

Horus sought to achieve a swift and decisive victory over the Emperor after pledging his soul to the service of the Ruinous Powers of the Warp, leading his Traitor forces directly to Terra seven standard years after the battles in the Isstvan System, slaughtering tens of billions of people and destroying much of what the Emperor had built over the last two centuries.

In a final decisive battle between the Emperor and Horus at the end of the great Siege of Terra in 014.M31, the Warmaster was slain, leading to the end of the rebellion when the forces of Chaos naturally began to turn on one another without Horus' ambition, titanic charisma and influence to keep them united in pursuit of a single goal.

Over the next several years, the Traitor Legions and their Chaos allies slowly withdrew from Human space, eventually fleeing Imperial pursuit into the great Warp rift in the Segmentum Obscurus known as the Eye of Terror.

However, the Master of Mankind was Himself mortally wounded during the battle, which took place on Horus' Chaos-twisted Battle Barge, the Vengeful Spirit, in orbit above Terra. The Emperor's body was recovered by the Primarch Rogal Dorn of the Imperial Fists Legion and according to His last instructions, the Emperor was placed on the life-preserving Golden Throne, an arcane artefact dating from the Dark Age of Technology that served as both a psychic amplifier and a potent cybernetic life-support system that the Emperor had originally intended to use to create his portal into the Webway.

For over 10,000 Terran years now, the Emperor has remained immobile on the Golden Throne. Though physically a broken, dying carcass incapable of movement and unable to communicate normally with the outside world save through the rare telepathic contact and the Emperor's Tarot, the Emperor's psychic will, almost omnipotent, extends through the Immaterium across the million worlds of the Imperium.

It produces the psychic beacon of the Astronomican that is used by all Imperial starships to travel through the Warp, soul-binds weaker psychic Humans to make them useful Sanctioned Psykers of the Imperium while leeching the lives from 1,000 other psykers every solar day to sustain His psychic presence, and struggles against the encroaching Daemons of the Warp, protecting Mankind from their realspace predations.

In all this, the Emperor endures the constant agony of His dying body only through a sheer exercise of will, and the sustenance that the life forces of the sacrificed psykers provide. Yet the masses of Humanity worship the Emperor as both a god and their only saviour. It is an article of faith in the Imperial Cult that against all the threats faced by the Human species, only the Emperor protects...

Great Scouring

In the wake of the Horus Heresy, the Imperium was a dismal, shattered thing. As the beauty and grandeur of the Imperial Palace had been burned black in the flames of betrayal, so great swathes of the Emperor's star-spanning realm had suffered a similar fate.

The Master of Mankind was a broken husk, and His dream of unity erased forever. Yet for all this, the Imperium retained might enough to exact a bloody revenge upon its foes. There could be no forgiveness for the crimes of the Traitor Legions -- those who now ruled in the Emperor's name had neither the ability nor the desire to prevent a war of reciprocity. So began the time known in the histories of the Imperium as the Great Scouring.

Before actually being confined for all time within the life-support mechanisms of the Golden Throne, the Emperor had pronounced judgment on the Traitors: he declared them Excommunicate Traitoris, and determined that they were to be driven into the hellish region of the Warp rift called the Eye of Terror, which would hold them for all eternity.

All records and memory of the Traitor Legions were to be expunged from the Imperial archives. Worlds such as Istvaan V, the Traitor Legion homeworlds and Davin would be scoured clean of all life because of their corruption by Chaos.

The Traitor Legions' associated troops from the Dark Mechanicum, the Titan Legions or the regiments and starships of the Imperial Army that had turned to Chaos were to be destroyed or also driven into the Eye of Terror. It would be as if the Traitor Legions had never existed to sully the Imperium with their betrayal.

This was a period of monumental violence, of confusion and darkness. Though the newly founded Imperium fought to root out corruption and expose wrong-doers to the cold light of Imperial justice, the galaxy's sheer scope and dark, shadowed reaches worked against them.

With new betrayals and cries for vengeance emerging daily, a great many bloody-handed deeds went unseen. The ravaged Space Marine Legions were no exception to this, with many striving to cover up their own misdemeanours or exact their pound of flesh from those who had wronged them.

The Dark Angels, the Space Wolves, Iron Hands and even the Ultramarines, all followed their own agendas as the wars of the Great Scouring gathered pace. Fighting continued for years after the Heresy had ended with Horus' death on the bridge of his great flagship before the Traitor forces were wholly destroyed or exiled into the Eye of Terror.

Many Chaos-corrupted star systems were cleansed and placed under the watch of the newborn Inquisition. Horus' death had not ended the fighting, but it had renewed the resolve of the Loyalists to destroy the Traitors.

Many Imperial worlds during the Heresy had refused to commit their forces to either side, or seceded entirely from the Imperium to regain their independence. Such indecision was punished by Loyalist and Traitor forces alike. These forces were often bled white attacking the rebel strongholds of worlds that only wanted to be free of the Imperium entirely, whether it swore allegiance to the Emperor or to the Dark Gods.

Changes swept both the Imperial military and the offices of government. The Space Marine Legions, the vast fighting formations so instrumental in Mankind's victories during the Great Crusade, were broken down into many smaller Chapters comprised of 1,000 Astartes. Overseen by Roboute Guilliman, the primarch of the Ultramarines Legion and the lord commander of the Imperium in the wake of the Emperor's "ascension," he penned his magnum opus, the Codex Astartes -- a great and sacred tome which covered every conceivable topic of military organisation, strategy and tactics.

This transition allowed for greater tactical flexibility without placing the command of an entire Space Marine Legion into the hands of one individual -- never again would the awesome power of one hundred thousand Space Marines be misused.

The Loyalist Space Marine Legions called the Shattered Legions that had been decimated during the Drop Site Massacre on Istvaan V -- the Raven Guard, Iron Hands and Salamanders -- were slowly reestablished using what little gene-seed the survivors had managed to escape with.

The original First Founding Space Marine Legions were divided into smaller Successor Chapters -- one Chapter maintained their parent Legion's original name, badge and colours, while the remaining Chapters took new names and heraldry. These original Chapters are known as the Second Founding Chapters, an event which occurred in the early 31st Millennium and coincided with the beginning of what was known as the Reformation of the Imperium.

Another vast change wrought upon the Imperium's mighty military redefined the nature of the Imperial Army. Once including both the great battleships that plied the stars and the countless mortal soldiers that landed to fight planetside, now the two were divided into the Imperial Navy and Astra Militarum, colloquially known as the "Imperial Guard."

Across all the agencies of the Imperium, offices and institutions were split, their previous responsibilities fractionalised into separate functions and departments. Many of the countless branches within the sprawling Adeptus Administratum were spawned at this time.

With the instigation of these changes, it was not unusual for two separate organisations, each unaware of the other, to be tasked with the same jobs, such as verificator scribes and tithe enumerators poring over the same data, each producing the same reports.

These byzantine systems were put in place as fail-safe measures, which have since spiralled out of control into administrative excess.

Beyond any such bureaucracies, and standing watch over all, was the newly formed Inquisition, a secretive paramilitary police organisation outside the established hierarchies. Ever vigilant, its role was to question everything in the constant search for threats to Humanity. None save the Emperor Himself escape the Inquisition's uncompromising and watchful gaze.

Imperial Stagnation

"Mankind stands upon the brink; on the one hand lies a realm of unimaginable power, on the other awaits darkness, death and utter damnation. Only those that follow the guiding light of the Emperor may save their souls."

Inquisitor Damarn, Ordo Malleus

The Imperium of Man at the end of the 41st Millennium is a dystopic society by the standards of the people of the 21st century. The unexpected horrors of the Horus Heresy fatally weakened the nascent Imperium, but more importantly, starting with the Emperor Himself, claimed some of its best warriors, technocrats, administrators and diplomats -- who fell either in battle with the Traitor Legions or were corrupted by Chaos themselves.

But perhaps the most significant consequence seems to have been that like the Emperor, the Imperium itself entered a slowly decaying stasis, while Chaos and the Imperium's myriad xenos enemies are ascendant.

It is known that the period immediately following the Heresy was one of near-anarchy, and that the continuity of the Imperium was not assured. Roboute Guilliman, the primarch of the Ultramarines, was one of those credited with taking decisive action that kept the Imperium together as its ruling Lord Commander, possibly with the help of other Loyalist forces and of new Imperial organisations such as the Inquisition and the Officio Assassinorum (the Assassin Temples had been secretly established during the Great Crusade by Malcador the Sigillite, and a Callidus Assassin had successfully assassinated Konrad Curze, the primarch of the Night Lords Traitor Legion).

Ironically, while the Imperium survived its first time of testing, it also seems to be fulfilling predictions or prophesies made about its future by a variety of Chaos enemies, Traitors, and more neutral or potentially sympathetic observers like the Craftworld Aeldari.

Supreme among such ironic twists is the deification of the Emperor and the attendant creation of the Ecclesiarchy, the galaxy-wide state church dedicated to the Imperial Creed that teaches that the Emperor is the god of Mankind. The Emperor's express purpose and one of the pillars of the pre-Heresy Imperial doctrine known as the Imperial Truth that was spread by the Imperial forces during the Great Crusade was the elimination of superstition and of belief in supernatural powers, gods, and religion and the promotion of reason and science.

It is worth noting that among the ploys used by the Ruinous Powers to turn Horus to their service were uncannily accurate visions of the post-Heresy Imperium in which the Emperor and His Loyalist primarchs were worshiped by the Imperial masses as a god and his saints, respectively. Of course, unknown to Horus, this was a future caused by his actions, not prevented by them.

Another measure of the Imperium's stagnation has been the lack of real technological progress over the last 10,000 Terran years and a fear of unknown or ancient technology that sometimes borders on irrational superstition. It seems that the last era of major Human technological advancement was the era of discoveries and technological applications made during the planning and execution of the Great Crusade.

In short, the Imperium has become a repressive regime marked by extreme levels of superstition, political repression, religious intolerance, bureaucratisation, economic stagnation, technological regression and inequality. Corruption and injustice are rampant and Human life is increasingly worth very little in a galaxy teeming with trillions of people.

But though the Imperium is repressive and stagnant, it is also the only thing holding the enemies of Humanity at bay. Many in the highest levels of the Imperium know that it must reform if it is to survive, but they fear that the cure might very well kill the patient.

And in small pockets of the Imperium there are men and women willing to shoulder the burden of making their small corner of the universe a better place for all by shouldering the responsibilities and the burdens of heroes.

Era Indomitus

Things have only been made worse with the birth of the Great Rift or Cicatrix Maledictum in ca. 999.M41, following the successful completion of Abaddon the Despoiler's 13th Black Crusade and the fall of the Fortress World of Cadia. The Great Rift is a massive Warp rift comprised of continuous and permanently raging Warp storms that now stretches across the galaxy from the Eye of Terror in the galactic west to the Hadex Anomaly in the east.

No one fully understands the origins of the Great Rift, though there are many theories: the breach of the Cadian Gate during the Despoiler's recent 13th Black Crusade, the sorcery of the Daemon Primarch Magnus the Red during the Thousand Sons' invasion of the Fenris System, catastrophe in the Webway, mass bloodshed and warfare between the Imperium and the T'au Empire in the Damocles Gulf -- all may have caused or contributed to it.

Its emergence was a literal galaxy-shattering event, which threw the Imperium of Man into chaos and ushered in new wars across nearly every world in the Emperor's domain. So powerful and far-reaching was this Warp rift that the very laws of physics fray at its edges as the inconsistencies of temporal fluctuations, once largely localised to larger Warp Storms such as the Eye of Terror, spread across the galaxy.

Some worlds felt standard centuries go by in an instant while others were all but frozen in time, and still others have suffered constant temporal shifts.

On the far side of the galaxy-spanning Warp rift from Holy Terra, things have quite literally gone to hell. There, the light of the Astronomican is obscured behind a psychic maelstrom of nightmares and the entire region has been dubbed the Imperium Nihilus, or the Dark Imperium. Many of those planets in the vicinity of the Great Rift have disappeared entirely, or been so corrupted that they are now labelled as Daemon Worlds. The regions of the galaxy on the near side of the rift, known as the Imperium Sanctus, still bathe in the light of the Emperor, but are under no less pressure from the still-growing threat of Chaos.

In response to the emerging forces of Chaos throughout the galaxy, the recently resurrected Roboute Guilliman, primarch of the Ultramarines, and now once more the lord commander of the Imperium and its vast armies, has launched his Indomitus Crusade. It is this campaign, with its Imperium-altering course, that has given its name to this new period of Imperial history, the Era Indomitus.

Gathering his new armada, along with elements of the Adeptus Custodes, a small contingent of the Silent Sisterhood, and a vast war host of Primaris Space Marines from many newly founded Chapters, the primarch and the other fleets of the crusade have set a winding course. Strike forces from over a dozen pre-existing Chapters of Space Marines, led by the Imperial Fists, have joined the Indomitus Crusade fleets.

Thus began many new legends as Guilliman and the other Indomitus fleets travelled to aid beleaguered Imperial planets, breaking sieges and sweeping away invaders to bring hope back to the desperate defenders. It was not long before word began to spread, as those worlds that could still receive astropathic messages hailed the return of a hero out of myth. Once more, one of the demigods of the past fought for the Imperium of Mankind.

Even so, in ca. 999.M41, the Adeptus Mechanicus secretly reported to the High Lords of Terra that in addition to all the other problems besetting the Imperium, the mechanisms of the Golden Throne are malfunctioning and they no longer possess the necessary knowledge to repair them.

Whether the nobles of the Imperium like it or not, the Imperium will either begin to change at the direction of its resurrected lord commander, or it will die, the throats of its people cut by the myriad wolves already circling its shattered realms...

Imperial Culture

A Legacy of Strife

The Human race of the 41st Millennium bears deep scars upon their collective psyche thanks to the horrors of the Age of Strife, which ground on for almost six standard millennia. Mankind survived its ravages in only the most fragmented and desperate fashion, emerging from its shadows and into the Emperor's light as a species much changed.

The collapse of Humanity's intersteallar society during the Age of Strife brought a violent end to millennia of Human confidence. It completely shattered the species' prior sense of galactic destiny. Never before had there been a peril or challenge Human ingenuity could not best. Worse, the dangers that laid Mankind low came from within, unmarked until it was too late.

The damage done to the gestalt Human psyche by thousands of Terran years of galactic catastrophe ran so deep as to become instinct; mistrust of curiosity and invention, of alien influence and psychic witchcraft predominated. Humanity became closed-minded and violently conservative, desperate to avoid repetition of the mistakes that had led to the horrors and intense suffering of the Age of Strife. Where lore and record-keeping failed, mythology and religion kept those fears alive.

Perhaps this explains the fervour with which the Emperor's Great Crusade was greeted. Though of course countless warlords and isolationist societies fought His rule, the Emperor's unification of the Human-settled galaxy brought a safe and secular comfort that banished the ghosts haunting the Human soul. If this is true then it would also explain why the Emperor's fall during the Horus Heresy saw those spectres rush back in with such vengeance.

Fearful and bereft of the Emperor's conscious guidance after His interment within the Golden Throne, Humanity sought strength in the blind zealotry that the Emperor Himself had so assiduously discouraged through the spread of the Imperial Truth, becoming ever more entrenched in their superstitions over time.

The Age of Strife even scarred the galaxy itself. Countless worlds were reduced to inimical wastelands or overrun by dangerous living weapons. Others were left haunted by the cyclopean ruins of lost endeavour, vast haloes of decaying orbital machinery, looming spires crackling with strange energies, echoing techvaults still concealing deadly threats behind bulkheads buried in the dust of ages.

Every time the Imperium discovers another such remnant of Humanity's former glory it is but another reminder of the hubris that damned Mankind, and the dangers of daring to hope in such a dark and terrible age as the 41st Millennium.


The Imperium of the 41st Millennium is a deeply superstitious society, its people bound in shackles of ignorance and blinded against dangerous truths. Atavistic terror and religious disgust characterise its attitudes to scientific and technological innovation, stemming from the barely remembered, apocalyptic horrors of the Age of Technology and Age of Strife.

Advanced science and technology is but dimly understood by the mass of Humanity. Be they erudite scholars, military heroes, the pilots of voidcraft or ragged serfs, the majority of Mankind attributes the operation of technology to fickle, animistic Machine Spirits that must be beseeched with the proper rituals of activation and appeased with offerings of sanctified oil, sacred unguents and the like.

Only the magi of the Adeptus Mechanicus possess true repositories of technological and scientific lore. They hoard all they have gathered in towering data-stacks deep within the industrial sprawls of their fortified factory-planets known as Forge Worlds. Yet even these insular tech-priests make no distinction between technical blueprint and sacred scripture, electronic component and holy relic.

Their prayers are delivered in blaring binharic cant, their repairs conducted as incense-wreathed rituals and the construction of their revered machines performed by rote rather than understanding. Experimentation, innovation and invention are considered tantamount to heresy.

The doctrines of their Machine God -- the deity whose physical manifestation is the Emperor or "Omnissiah" -- grew out of the terrors of the Age of Strife and warn of the dangers of rampant innovation. Knowledge lost to the ravages of time remains lost, for the terror of tech-heresy -- or at least, of its discovery and the subsequent punishment -- is greater by far than the dread of ignorance.

For all this the Adeptus Mechanicus holds vast power in the Imperium, which is reliant upon advanced technology to survive. There is a reason that worship of the Omnissiah is the only officially tolerated religion besides the Imperial Creed. Nor do the Adeptus Mechanicus view the acquisition of lost technologies --archeotech -- to be in any way equivalent to the sin of fashioning devices anew.

There is an irony long lost on the tech-priests that they hunt rapaciously for even the slightest fragments of ancient Human artifice, many of which are examples of the very Dark Age technology so reviled by their own creeds.

Such relics of the Omnissiah are viewed as sacred treasures; entire armies are readily sacrificed to ensure their acquisition. Most precious of all are the remnants of Standard Template Construct machines that have survived the long Terran millennia. These remarkable STC databases allow auto-fabrication of devices that Humanity can well use in their war for survival; many of the Imperium's most ubiquitous weapons and war engines are still produced in this fashion.

The Imperial Creed is as damming of unsanctioned technology as it is of mutation or rebellion against the Emperor. Many allegorical parables warn against the horrors of artificial general intelligence; such "thinking machines" are regarded with horror, and are banned even amongst the Adeptus Mechanicus.

The average Imperial citizen views tech-heresy as akin to witchcraft, and reacts with equal intolerance to either. Some Human worlds play host to ancient sites where the remains of Dark Age technology lurk, but these are shunned as cursed by those forced to live in their shadows. Xenos technology is even further mistrusted; even the most replicable and galaxy-changing innovations are typically shunned if they are of alien origin. There are exceptions; dangerous archeotech sometimes finds its way up from the lawless roots of hive cities or mine workings after being excavated by labour gangs.

Frontier World colonists -- who take a more pragmatic approach to survival than those who live on the more settled worlds of the Imperium -- trade with neighbouring xenos species, and in so doing introduce xenotech to the sprawling Imperial black markets. Such dangerous prizes are sought out by various ordos of the Inquisition, of course, as are their suppliers, for the damage that these deviant devices can cause in the wrong hands does not bear imagining.

Adeptus Terra

Structure of the Imperium of Man

The feudal structure of the Imperium of Man

The Imperium covers a wide area of galactic space, sprawling over countless worlds. There are few universal constants amongst these wildly varying planets. Culture, language and even the Human form appear in seemingly infinite variation across the galaxy.

One of the few constants (at least amongst those worlds of the Imperium that are aware of its existence) is the network of Imperial feudal obligation and responsibility. Each Imperial planet owes fealty to a planetary governor. This individual in turn renders to the Imperium's governing priesthood a tithe of troops, materials and loyalty.

Every planetary governor is also expected to reject enemies of the Imperium, and to ensure that the psykers upon their planet do not fall into witchery or Daemonic possession. In return, the governor can call upon the Priesthood of Earth -- or Adeptus Terra as they are properly known -- in times of dire threat and request aid.

The Adeptus Terra comprises a bewildering variety of departments, bureaus, sub-divisions and offices, each of which deal with a particular aspect of maintaining the continuity of the Imperium. Each order has an obligation to care for its given area of control.


The structure of Imperial authority

This weight of responsibility grows as feudal obligation passes up through a mind-numbing array of ranks within each adepta. From lowly scribes computing a Hive World's annual nutra-slurry yield to mighty Sector Commanders overseeing the assemblage of an Imperial Crusade fleet, vassalage and power passes ever upwards to the titular heads of the Imperium, the High Lords of Terra.

These powerful individuals rule from ancient Terra in the Emperor's name. Based on Terra itself, the Emperor of Mankind is a silent being of awesome power. His withered carcass is cradled within an arcane artefact of incredibly advanced design from the Dark Age of Technology. This Golden Throne, as it is known, sustains the Emperor's life force whilst He guards Humanity from the Daemonic beings in the Immaterium that would destroy Mankind utterly. For hundreds of standard centuries He has fought this psychic battle and for hundreds of centuries Mankind has offered Him their fealty, worship and devotion.

Imperium Structure & Organisation

Chart depicting the structure and organisation of the various organisations of the Imperium of Man.

The Imperium is still nominally ruled by the Emperor of Mankind as an absolute monarch. However, since His ascension to the Golden Throne, the duty of actual high-level governing of the Imperium falls to the Senatorum Imperialis -- the Imperial Senate, formed by the 12 High Lords of Terra.

The identities and responsibilities of these High Lords may vary, as individuals inevitably die and their influence grows and wanes, but its members are always the leaders and representatives of the most powerful Imperial organisations. Since the birth of the Great Rift at the start of the Era Indomitus, the Senatorum Imperalis has been led once more, as it was in ancient times, by the Lord Commander of the Imperium and Imperial Regent, the Primarch Roboute Guilliman. Guilliman is now the first among equals of the High Lords, and the others hold their positions only at his whim.

Ultimately, the High Lords are in control of the Imperium as a whole, and are responsible for maintaining the functioning of the Imperium through the Adeptus Terra and the Imperial Commanders who govern each Imperial world, sub-sector, sector and segmentum. However it is not feasible to maintain a completely centralised government over such vast interstellar distances, even with faster-than-light travel and astro-telepathic communication.

This means that the Imperium is structured like a neo-feudal confederacy, with the planetary rulers acting as feudal lords subject to the higher authority of the Adeptus Terra and responsible for providing troops to the Astra Militarum, but largely free to run their worlds day-to-day as they see fit. Therefore, many Imperial worlds are left to fend for themselves without any direct involvement of the central government save in a time of crisis.

The flow of information in the Imperium is tightly controlled, with several Imperial bodies withholding information (chief among these is the Inquisition, an ever-present censor) or engaging in deliberate misinformation and the spread of propaganda (such as the Ecclesiarchy among others).

Other organisations zealously protect information that could be used for the benefit of the Imperium as a whole, such as the widespread hoarding of technological and scientific information that is the common practice of the Adeptus Mechanicus. The censorship has been justified by the terrible and dangerous nature of some of this information, and by the sheer immensity of the task of governing the Imperium.

The stellar empire that is the realm of the Emperor is so massive and sprawling that it includes a wide variety of diverse worlds, ranging from pastoral Agri-worlds to jungle planets inhabited by Neolithic savages to polluted ecumenopoleis, great hive cities that are home to billions of people that in some cases cover entire planets.

For example, the world of Gudrun is similar to an idyllic 18th century Georgian-era Great Britain, with stately manors controlling vast estates of rolling green hills studded with small agricultural villages, while Catachan is a hellish Death World covered in a deadly jungle that is populated by giant carnivorous plants and animals (see Planets of Warhammer 40,000).


The Imperial organisations of the Adeptus Terra exist within a complex web of power; sometimes they are allies, at other times they actively work against each other in byzantine and sometimes violent conflicts.

Most of the organisations or organs comprising the Imperium's government are divisions of the vast Adeptus Terra, the great bureaucracy of the Imperial government. This Priesthood of Earth which serves the Master of Mankind is often referred to as "the right hand of the Emperor."

It falls to the Adeptus Terra to interpret His will and minister to the Imperium. Many hundreds of thousands of souls labour across the galaxy to serve this vast organisation. There are numerous ancient institutions that make up the priesthood, each with various names on various planets. These varying "adepta," as they are traditionally known, each have a specific function to carry out in the Emperor's name.

There are countless divisions within the Adeptus Terra, and some are so secretive that their existence is known only to a few officials at the very top of the massive Imperial hierarchy. Perhaps the most well-known of the "secret" organisations is the Inquisition, the Imperium's secret police, which was created in its earliest form during the Horus Heresy by the Emperor's regent, Malcador the Sigillite, to seek out any hidden threat to the Imperium from without or within.

The existence of the other secret Imperial organisations is known only to the higher Imperial echelons. For example, one of the most secretive of Imperial organs is the Officio Assassinorum, the arm of the Imperium tasked with carrying out assassinations deemed necessary to the Imperium's continued security and survival.

Other organisations are secret enough that nothing other than the fact that they exist is known, such as the saboteurs of the Officio Sabatorum and the Templars Psykologis, who carry out psychological warfare operations.

The most important and well-known Imperial adepta include:

  • The Adeptus Administratum, which is responsible for the day-to-day administrative and bureaucratic functions of the entire Imperium. The Administratum is the largest division of the Adeptus Terra, and contains among its teeming numbers of Adepts countless scribes and petty officials. It administrates the Imperium at every level, assessing tithes and taxes, conducting population censuses, recording and planning and even delineating which threats to the Imperium must be dealt with and by which of the Imperium's myriad military forces. The Administratum consists of innumerable subdivisions, offices and departments. Needless to say, its servants are legion. At the will of the Adeptus Terra, the Administratum collects the Imperial Tithe, sends out colonists, mobilises the military, catalogues planets and much, much more. Truly stultifying levels of bureaucracy exist within the Administratum and some wayward souls believe that the Imperium survives despite, rather than because of, its efforts. The Administratum has become synonymous with the Adeptus Terra in many places and, incorrectly, the terms are often used interchangeably. The faceless servants of the Administratum can be found all over the Imperium, ensuring that all things are accomplished in the correct manner, even if that may take a thousand standard years.
  • The Departmento Munitorum, also called the Adeptus Munitorum, is a department or sub-division of the Adeptus Administratum devoted to the general administration, personnel assignment, supply and logistics of the Astra Militarum. The Munitorum has ultimate responsibility for the raising of new Imperial Guard regiments, the training of new Imperial Guard troops, the provision of equipment and supplies to all regiments in the field, and the transportation of troops and equipment to and from theatres of war using the vessels of the Imperial Navy. It is primarily a logistical organisation, like the larger Administratum of which it is a part, but while the Administratum deals with the civilian logistics of running the entire Imperium of Man, the Munitorum deals solely with the military logistics necessary to fight and win the Imperium's wars on behalf of all branches of the Imperial armed forces.
  • The Adeptus Astra Telepathica is the Imperium's network of Astropaths, the Sanctioned Psykers who are responsible for astro-telepathically transmitting faster-than-light messages through the Immaterium and maintaining Mankind's fragile network of interstellar communications across the galaxy. Blessed are the blind Astropaths, for they have looked upon the glorious light of the Emperor directly and no true servant of the Golden Throne could ask for more. Through the agonising ritual of soul-binding, these psykers have been gifted with a small portion of the Emperor's own incredible will. Thus protected from the worst evils of predation by Warp entities, these unseeing servants of Terra can fulfil their primary function, preserving communication between the far-flung worlds of the Imperium.
  • The Adeptus Astronomica is the Adepta responsible for maintaining the Astronomican which is used by the mutant psykers known as Navigators to navigate all Imperial starships, military or civilian, through the Warp. The Black Ships of the Adeptus Astra Telepathica bring thousands of psykers to the birthplace of Mankind every day and many of those so tithed find themselves contributing to the vast psychic choir of the Astronomican. This steady beacon burns bright in the Warp; it is the Emperor's will made manifest, shining from Terra, and guides Navigators across the Imperium. The process of lending their psychic power and life force to power the beam quickly leaves the choristers as lifeless husks, but they give themselves willingly, for without the Astronomican the Imperium would cease to exist. The organization is based in Terra's Forbidden Fortress, where even the Adeptus Arbites' Judges and Inquisitors must receive an invitation to lawfully enter. The Adepta's head is the Master of the Astronomican, who represents the organisation as a High Lord of Terra and a member of their Senatorum Imperialis.
  • The Navis Nobilite is an ancient organisation of mutant Terran nobility predating even the creation of the Imperium of Man by several thousand standard years. It is comprised of noble families who are all Human mutants called Navigators who have the unique psychic ability to navigate spacecraft through long distances in the chaotic transdimensional eddies of the Warp. The Great Houses of the Navis Nobilite are some of the wealthiest and most politically powerful collections of nobles in the Imperium.
  • The Adeptus Mechanicus is the priesthood of technicians and scientists dedicated to the religion of the Cult Mechanicus who build and maintain all advanced Imperial technology, vehicles, starships, and weapons of war and whose headquarters is located on Mars. The Adeptus Mechanicus believes that all knowledge in the universe is a sacred emanation of the Machine God and that the Emperor of Mankind is His Omnissiah. Needless to say, the Tech-priests and Adepts of the Mechanicus are viewed as only slightly better than the average Heretic to the Priests of the Ecclesiarchy. Outside of Mars, the Mechanicus controls all of the Imperium's Forge Worlds, the planets where the production of most of its advanced technological items is done. The domains of the Adepts of Mars exist semi-autonomously within the Imperium, an empire within an empire, a right given to them by the Emperor Himself when he signed the Treaty of Mars that created the modern Imperium in the 30th Millennium. They are the guardians of technology, the magi of machinery. It is theirs alone to know how to coax forth the life of a sun in a plasma containment field, how best to apply the blessings of activation and maintenance to the massive Titan war machines, how to ensure that the engines of the Emperor's starships run smooth and true. The Adepts of Mars worship the Emperor in the guise of the Machine God. To them, Mankind is in a fallen state from the height of its powers during the Dark Age of Technology, when the secrets of the universe were known to all. Knowledge then, lies in the past and the Adeptus Mechanicus will go to any lengths to uncover the great secrets of antiquity, scouring the universe for any scrap of information from their holy book -- the lost Standard Template Construct database system. They hold that, were the knowledge contained within the ancient STC database to be restored in full, it would reveal all of the powers of the hallowed past. The Tech-priests venerate machines and regard them as superior to flesh. Many of them believe that the Machine God desires them to shed this weakness and so they often sport numerous bionic modifications. These mechanical enhancements add to their air of otherness and further help to set them apart from the rest of Humanity. Through rune and hammer, the Tech-adepts are the wards of the arcane and they guard their knowledge jealously. But for all their might, they are not beyond the watchful gaze of the Inquisition.
  • The Adeptus Custodes are the genetically-engineered superhumans who serve as the guardians of the Emperor's physical form. They are essentially the Emperor's bodyguards and royal guardsmen within the Imperial Palace on Terra and they are considered the greatest warriors of the Imperium, more powerful than even the Astartes of the Space Marines. However, despite their skill in battle they very rarely ever venture beyond the confines of Terra. These are among the mightiest warriors in all the Imperium, the praetorians of the Emperor. They stand ever-vigilant outside the brazen doors which seal His holy chamber. They are entirely beyond reproach and they are among the few in the Imperium over whom the Inquisition has no power. They never leave the inner sanctums of the Imperial Palace and serve from birth to death within its hallowed halls. Yet they are among the few servants of Mankind who will ever look upon the Emperor directly, and for that they receive blessings beyond all measure.
  • Adeptus Arbites - The Adeptus Arbites are the guardians of the Lex Imperia -- Imperial Law. It is given to them to maintain order amongst the higher echelons of Imperial governance -- wherever a Planetary Governor seeks to abuse his rule, wherever populist unrest seeks to unseat the rightful dominion of the Imperium, wherever thoughts of personal gain at the Emperor's expense cross the minds of the ruling classes, there you will find the dogged agents of the Lawgivers. The Arbites enforces Imperial Law across the galaxy and its Arbitrators possess the right to serve as judge, jury and executioners on every Imperial world.
  • Officio Assassinorum - The Officio Assassinorum is the most covert of all the known Imperial agencies, whose superhuman Assassins are responsible for removing the key leaders of any enemy of the Imperium as determined by the High Lords of Terra -- whether that enemy is a threat from without or within.
  • Holy Ordos of the Emperor's Inquisition - The Imperium is assailed by countless enemies both from within, without and beyond the boundaries of reality. The attentions of unclean xenos, the invidious influences of the misguided followers of the Ruinous Powers, planetary unrest, mutation, rogue psykers, rebellious Imperial lords and more all work constantly to bring the Imperium down, which will lead to the ultimate extinction of Mankind. Yet somehow it survives and Humanity endures. The Inquisition is one of the many reasons for the persistence of Man in an extremely hostile universe. Known as the "left hand of the Emperor," the Inquisition, itself not officially a part of the Adeptus Terra but standing above it, operates across the Imperium and beyond to suppress and eliminate those forces that would destroy the holy dominion of Mankind over the galaxy. Inquisitors are empowered to go anywhere and do anything -- whatever they must to ensure the survival of the Imperium and Humanity. Their Inquisitorial Rosettes open all doors, and even the vaunted planetary governors must acquiesce to their demands without complaint or delay, lest they be themselves regarded as suspect. They will commit acts, no matter how vile, to maintain the unchanging integrity of the Imperium, and they will put whole planets to death in order to see that this is so. The members of the Inquisition vary enormously in physical appearance, methodology and mentality. Some operate alone and in secret, hidden from the eyes of the common man, while others operate openly and carry dozens of Acolytes and agents in their cadre. What they do have in common is that they answer only to their order, and each order answers only to the Emperor. Their efforts can be checked by no adepta and they are utterly, fanatically devoted to the defence of the Imperium. Even the most loyal and honest Imperial citizen is likely to break into a cold sweat on learning that the Inquisition is nearby -- and that suits its members perfectly. The Inquisition is itself divided into three major orders or "ordos": the Ordo Malleus, which hunts Daemons and those corrupted by the Ruinous Powers of Chaos; the Ordo Xenos which eliminates the threat that other intelligent alien civilisations present to Humanity's rule of the galaxy; and the Ordo Hereticus which hunts down mutants, witches, Heretics of the Imperial Cult, and all those who would threaten the Imperium from within -- including within the Ecclesiarchy itself. The Inquisition's agents necessarily exist and operate beyond the control of the Adeptus Terra, since part of the Inquisition's role involves rooting out corruption and gross incompetence from within the highest levels of the Imperium itself. Inquisitors ultimately answer only to the Emperor and to themselves and they are perhaps the most powerful organisation within the Imperium after the Chapters of the Adeptus Astartes.
  • The Adeptus Ministorum is the ecclesiastical hierarchy of the Imperial Cult that serves as the state church of the Imperium and promulgates and maintains control of the Imperial Creed and the galaxy-spanning faith of the God-Emperor of Mankind. The Adeptus Ministorum is not formally part of the Adeptus Terra. Rather it is a sister organisation which works hand-in-glove with the Priesthood of Earth. The Adeptus Ministorum derives its power and authority from the common Imperial belief in the Emperor's divinity. Also known as the Ecclesiarchy, after its high priest, the ruling ecclesiarch, the Adeptus Ministorum is vast and powerful. Its duty is to guide and interpret the innumerable ways that Humanity has found to worship the Emperor, shepherding the myriad worlds of Man along the unsteady path that lies between heresy and true devotion. Whole worlds lie within its administration and on many others it represents the most powerful Imperial institution. Like the Administratum, the Ecclesiarchy is a complex and byzantine organisation. A bewildering hierarchy of priests, confessors, cardinals, novices, clerics, bishops and missionaries all owe fealty to the Ecclesiarch in the Ecclesiarchical Palace on Terra. Just as varied are the various roles within the Ministorum, from wandering Missionaries, to charismatic preachers and theosophical scholars. Two of the most famous institutions within the Adeptus Ministorum are the training orphanages of the Schola Progenium and the battle-sisters of the Orders Militant of the Adepta Sororitas.

Imperial Military Forces


A selection of close combat and ranged weapons commonly used by the military forces of the Imperium.

Mankind has always excelled at the art of war, and the Emperor's armies are spread across the galaxy. The threat or effects of war are never far away, no matter where you go in the Imperium. Mankind seeks to purge the stars of its enemies, and the bloody carnage it wreaks in doing so shows no sign of abating. The Imperium's military is at once mighty, glorious and terrible. Some of the most important military forces of the Imperium include:

  • Astra Militarum - The Astra Militarum or "Imperial Guard" is the backbone of the Imperium's military might. Millions upon millions of well-trained men and women, organised into thousands of regiments, make up the Guard. With Lasgun and bayonet they march upon alien battlefields and garrison vital worlds. They form the Imperium's first line of defence and they strike the first blow in many Imperial Crusades. Its regiments are drawn in great tithes of manpower from the Imperium's worlds and each regiment has a unique cultural character and fighting tradition, from the rigid discipline of the Armageddon Steel Legion to the stealthy brutality of the pale-skinned Stygians and the unflinching bravery of the Vostroyans. Vast conscript armies, elite special forces, massive tank columns and glorious sabre-wielding, animal-riding cavalry can all be found in the Imperial Guard, often fighting alongside one another on Emperor-forsaken worlds they have never heard of. Regiments do not remain on their homeworlds but are raised explicitly to be sent to fight and die light years away from home. And they do die, for the Imperial Guard bear the weight of the Imperium's wars. It is said that the Emperor knows the name of every soldier that has fallen fighting in His wars -- but if that is true, He is the only one who can comprehend just how many Imperial Guardsmen have died in the ten thousand years since the Emperor "ascended" to the Golden Throne. Those who survive the grinding horrors of a lifetime of war are frequently gifted a portion of the very land they fought to conquer as a reward. As with many things in the Imperium, this is a mixed blessing indeed. The Imperial Guard regiments are raised from the local armies of the Imperium's worlds as part of a planet's tithe to the Imperium. These regiments are normally deployed according to the orders of the Adeptus Terra. However, when the High Lords of Terra declare a major military campaign (often referred to as a "Crusade") they appoint a Warmaster chosen from among high-ranking Imperial Guard officers to command the campaign's regiments. One of the most famous Warmasters, Macharius, was given the title "Lord Solar" when he became the Imperial Commander of the entire Segmentum Solar. Macharius proved to be the greatest Imperial general since the Horus Heresy when he conquered a thousand worlds on the Imperium's Eastern Fringe and expanded the Imperium to the very edge of the Astronomican's reach.
  • Adeptus Astartes - The Adeptus Astartes, better known as the Space Marines, are the elite, transhuman warriors of the Imperium. They are few in number and regarded with almost mythical awe by most folk, for they are inheritors of traditions founded by the Emperor Himself. The Space Marines are divided into Chapters, each possessing 1,000 Astartes along with its own support staff and starfleet. It is said that there are around a thousand such Chapters in the Imperium. A Space Marine is recruited in adolescence from among the most violent cultures of the Imperium. His body is hugely enhanced with new genetically-engineered organs promoting muscle and bone growth to give him immense strength, size and resilience. His mind is similarly enhanced; hypno-doctrination and sleep-learning give him both a fervent belief in the Imperium and the knowledge of weapons and tactics to bring the Emperor's wrath to the battlefield. Upon completing his augmentation and training (which not all Aspirants survive), he is issued with his wargear, including a suit of Power Armour. This armour is one of the most powerful symbols of Imperial might, depicted in statuary and stained-glass windows in cathedrals all across the Imperium. Equipped with nerve-fibre bundles so it moves in sync with his body, a Space Marine's armour not only grants him great strength and protection but is a work of art, resplendent in the heraldry of his Chapter. Each Chapter is independent from the Adeptus Terra. While most will eagerly answer the summons of an Imperial Warmaster or a plea for help from somewhere in the Imperium, some Chapters have their own agendas and cannot be relied upon entirely. All, however, serve the Emperor loyally with complete devotion. All Chapters have proud traditions and distinct characteristics that translate into the way they fight. The ferocious Space Wolves, for instance, are more fiercely independent from the Adeptus Terra than most other Chapters and fight on their own terms up close with Chainswords and Bolt Pistols. The Iron Hands, on the other hand, have close ties to the Adeptus Mechanicus and are the masters of siege warfare, arming their warriors with an array of devastating heavy weapons and tanks. Many Chapters are legends, and names such as the Blood Angels, Ultramarines, Dark Angels and Imperial Fists are spoken of with reverent awe among Imperial citizens. A Space Marine Chapter has its own fleet of fast spacecraft and can react far more quickly to a threat than the Imperial Guard or Imperial Navy, making the Adeptus Astartes one of the only forces in the Imperium that can mount a rapid response to a crisis. The Space Marines are extremely few in number compared to the size of the Imperium and few citizens will ever see one in the flesh, but without them the Imperial military and the Human species would slide ever faster towards destruction.
  • Grey Knights - The Space Marines of the Grey Knights Chapter are amongst the most highly specialised of the Adeptus Astartes, designed to specifically defend the Imperium against the threat of Chaos. The Grey Knights are permanently attached to the Ordo Malleus as its Chamber Militant and their leaders are rumoured to serve terms as members of the Inner Conclave of the Inquisition. No ordinary warriors, Grey Knights are chosen from amongst the most fearsome and savage feral cultures, each one an emergent psyker who has undergone arduous tests of faith, strength, endurance and courage that would break all but the strongest. Grey Knights fight in baroque, heavily ornamented suits of Power Armour, carrying mighty sigil-encrusted swords and halberds. These warriors alone can stand before the might of a Greater Daemon with any hope of banishing it back to the Warp. The millennia the Grey Knights have spent in battle against the Forces of Chaos has furnished them with blasphemous knowledge, painstakingly pieced together by the Inquisitors of the Ordo Malleus. Each warrior carries a copy of the sacred Liber Daemonica, the holy battle rites of the Chapter, in a Ceramite case on his breastplate, and it is this tome which symbolises a Grey Knight's most potent weapon: his unshakable faith in the Divine Emperor of Mankind. For above all else, the Emperor protects...
  • Deathwatch - The Space Marines of the Deathwatch are mysterious figures who battle in black Power Armour, fighting with preternatural skill and dedication against the most terrible of alien creatures or xenos, as they are called in the Imperium. They usually appear without warning and vanish as quickly as they arrived, leaving no trace of themselves or of the creatures they have fought. These are the Imperium’s most highly trained xenos fighters, known simply as the Deathwatch. Forming the Chamber Militant of the Inquisition's Ordo Xenos, the Deathwatch uniquely draws its members from across the many different Space Marine Chapters, all of which have sworn sacred oaths to maintain specially trained xenos fighters and stand ready to deploy them at a moment’s notice when the Inquisition requests their aid. These specialised warriors are drawn together as and when needed by the Ordo to combat alien menaces whenever and wherever it rears its vile head. Rumour has it that Ordo Xenos maintains a number of secret fortresses at the fringes of the Imperium where the Deathwatch keeps a silent and constant vigil, ever watchful for the tell-tale signs of alien encroachment.
  • Collegia Titanica - The Collegia Titanica is the division of the Adeptus Mechanicus that includes the Legions composed of Titans, the colossal Imperial robotic war machines that are the most powerful engines of war in the Imperium of Man. The Collegia is also more rarely known as the Adeptus Titanicus (a contraction of "Adeptus Mechanicus Collegia Titanica").
  • Sisters of Battle (Orders Militant of the Adepta Sororitas) - The Orders Militant of the Adepta Sororitas, also known as the Sisters of Battle, are an all-female division of the Imperial Cult's ecclesiastical organisation known as the Ecclesiarchy or, more formally, as the Adeptus Ministorum. The Sisterhood's Orders Militant serve as the Ecclesiarchy's fighting arm, mercilessly rooting out corruption and heresy within Humanity and every organisation of the Adeptus Terra. There is naturally some overlap between the duties of the Sisterhood and the Imperial Inquisition; for this reason, although the Inquisition and the Sisterhood remain entirely separate organisations, the Orders Militant of the Sisterhood also act as the Chamber Militant of the Inquisition's Ordo Hereticus. The Adepta Sororitas and the Sisters of Battle are commonly regarded as the same organisation, but the latter title technically refers only to the Orders Militant of the Adepta Sororitas, the best-known part of the Adepta. The Sisterhood serves as the Ministorum's only official military force because the Decree Passive laid down by the reformist Ecclesiarch Sebastian Thor held that in the wake of the Age of Apostasy of the 36th Millennium, the Ecclesiarchy cannot maintain any "men under arms." This was supposed to limit the power of the Ecclesiarchy. However, the Ministorum were able to circumvent this decree by using the all-female force of the Sisterhood.
  • Navis Imperialis - The Imperial Navy holds nearly all of the Imperium's fighting starships; local governments, Warmasters and others are forbidden to maintain their own fleets of warships. Their spacecraft include some of the most potent engines of destruction in the whole galaxy, including mighty Battleships thousands of years old. The Navy's starships range from small Escorts with a crew of a few dozen to the immense Emperor-class Battleships which might have 20,000 souls or more on board. The Navy also includes fighter and bomber crews and aircraft of the division known as the Aeronautica Imperialis that support the forces of the Astra Militarum on the ground. The Navy's officer class is highly traditional and aristocratic in character. The Imperium's noble families frequently boast naval officers among their number and naval dynasties dominate many battlefleets. Elitism is a virtue on most ships, where the officers' lives are in stark contrast to those of the ratings and engine crews. With thousands of crew living and dying on ships that can spend solar decades without seeing port, a ship of the Imperial Navy becomes a city in space. Mutinies are not unknown and the Naval security battalions of Armsmen are a familiar sight on the decks of all naval ships, their black visors and Shotguns constantly reminding the men that obedience is their duty to the Emperor. The Navy relies on many other organisations to function. Perhaps most importantly, these ancient and complex vessels could not function without a complement of Tech-priests who know how to appease the starships' Machine Spirits and maintain technology that is too old and mysterious to be replicated. The Navy is also reliant on the Tech-priests of Mars for refits, upgrades, repairs and new starships. It is usual for a warship to have Astropaths on board, for proper communication is essential if the Imperium is to be defended. Many captains are glad to have Ministorum clergy among their crew, ministering to the spiritual needs of the men and steeling their spirits with sermons. Commissars are appointed to the larger ships, watching over the moral fibre of the crew and providing a watch against mutiny and impiety. Then, of course, there is the Navigator of each vessel, whose family can occupy entire spires jutting out into space atop the ship.
  • Militarum Tempestus - The Militarum Tempestus, also known as the Ordo Tempestus, is amongst the most rigidly codified of all Imperial organisations, for its men form the elite backbone of the Astra Militarum, serving as its special operations units. Though the Ordo is technically a sub-faction governed by the Adeptus Administratum, it enjoys a far greater amount of autonomy than the Imperial Guard regiments that often fight alongside it. The Ordo's ranks are primarily comprised of Commissars and the special forces troops known as Tempestus Scions or "Storm Troopers" in Low Gothic, though they have often included specialist factions mysteriously absent from Imperial records. In every theatre of war across the galaxy, the Ordo's men work alongside the incalculable might of the Astra Militarum, their elite training complementing the sheer manpower of the Imperial Guard. The regiments of the Tempestus Scions, no matter how skilled, do not form the main body of the Astra Militarum, for that duty falls to the regular Imperial Guardsmen. Instead they can be likened to a knife, a thrusting point of lethal force that is applied with shocking speed into the foe's weakest point. Many a grinding war of attrition or extended campaign has been brought to a dramatic close by a strike force of Tempestus Scions. More often than not, their insertion, mission completion and extraction parameters are all accomplished on the same day.
  • Inquisitorial Storm Troopers - The Inquisition maintains its own own corps of highly-trained special operations forces who are similar to the Militarum Tempestus's elite Tempestus Scions that guard the secret installations of the Inquisition. The Inquisition maintains a number of fortresses throughout the galaxy, both secret and known to the inhabitants of the Imperium. Inquisitorial Storm Troopers are used by the Imperial Inquisition to guard their fortresses and the Black Ships as they make their purity runs across the Imperium's sectors, and they also augment an individual Inquisitor's personal forces with reliable and effective soldiers. Many Storm Troopers of particular skill are chosen to become an Inquisitor's Throne Agents. Inquisitorial Storm Troopers are selected from families with a record of unwavering faith in the Emperor and prior duty to the Inquisition, usually from the Schola Progenium, just like their Tempestus Scion counterparts. They are trained and equipped in a manner similar to Ordo Tempestus Storm Troopers, albeit lacking the rapid insertion and infiltration skills, as they are not expected to undertake such types of missions which are more often carried out for the Inquisition by the Officio Assassinorum.

Imperial Faith

Imperial Cult

Adeptus Ministorum Icon

The Sigil of the Adeptus Ministorum

The Imperial Cult is one of the few common factors that link the disparate worlds of the Imperium together. No matter what conditions prevail upon a world within the Imperium, the Imperial Cult will be found there. The ways in which the Emperor is worshipped in Human space are multitudinous. To some He is revered as a distant, patriarchal and Human figure. Others identify Him with some aspect of nature, many others, such as the primitive Epheisians of Dwimlicht, regard Him as a Star God, for His agents only visit occasionally and they descend from the heavens when they do so. But all the creeds of the Cult agree upon this one thing: there is only one God-Emperor. To worship a pantheon of hods and put other gods alongside Him is heresy. However, there have been many individuals over the millennia who have been seen as His saints, people visibly touched by the Emperor, and they are venerated all over the Imperium. There are saints for every aspect of life and there is a thriving trade in their relics on many worlds.

The worship of the God-Emperor is, in the main, highly organised across the Imperium. Cathedral complexes can be found in the capitals of all worlds of any meaningful populations. On the densely populated, teeming Hive Worlds, these can occupy entire spires. The graceful structure of the Cathedral of the Emperor Triumphant, constructed after the Second War for Armageddon at Hive Primus on Armageddon, climbs delicately skyward, its main tower nearly a full kilometre in height. The statue of the Emperor at the top brushes the planet's troposphere, looking benignly down upon the seething, polluted Hive World below. Most towns will have a church or temple dedicated to the Emperor and even the crudest village of the most primitive tribesman will sport a sacred cave or grove dedicated to His name. Of course, in some places, the worship of the Emperor supercedes all other aspects of life -- these are the Shrine Worlds of the Imperium, where perhaps one of the great saints, or even, in the distant past, the Emperor Himself, performed a great deed.

These planets can be one, vast, religious complex, or huge cemetery worlds such as Granithor, where the wealthy spend vast fortunes bringing the dead scions of their families for burial, usually those who have perished in the service of the Emperor. Then there are the Cardinal Worlds, which attract millions of pilgrims and are the strongholds of the Imperial Cult. These planets are directly governed by the Ecclesiarchy and are the seats of functionaries high in the Cult, responsible for the spiritual health of vast areas of Human space. The Ecclesiarchy maintains and promotes the Cult galaxy-wide and, where possible, tries to sanction the worship of the Emperor no matter how bizarre it may seem. Very few practices are proscribed, and even such abominations as Human sacrifice to the Emperor are useful to the Imperium, for it is easy to convince a newly encountered culture that approves of such custom to give up its psykers to the Black Ships.

One of the Ecclesiarchy's tasks is to record this multiplicity of tradition with which the Emperor is honoured. In that way, two Preachers from opposite sides of the galaxy will know, no matter what their title or manner of expressing their devotion might be, that neither is a Heretic. The Ecclesiarchy sends out mission fleets for precisely this purpose, whose flotillas of blessed spacecraft slowly circle a particular part of the galaxy, recording new variants of the Cult, correcting serious heresies and proselytising to newly discovered populations of Humans. To all, the Emperor is a living god. He may be tens of thousands of light years away, but that He exists, the inhabitants of the Imperium know, so faith is an easier thing in the 41st Millennium than it has been at other times in Human history. Some amongst the Ecclesiarchy and Inquisition may argue that men should be more ardent in their devotion to Him, but though some may be lax in their adulation and may blaspheme or heretically curse the Master of Mankind for their lot, it is nevertheless rare to meet a man who would dare to deny the Emperor's divinity.

The Ecclesiarchy presides over the souls of the Imperium's citizens, dividing its countless dioceses into parishes, some of which are centred upon a particular planet, others focused to tending to a particular locale or holy shrine. Each parish is ministered by a priest called a Preacher, seeing to the well-being and purity of his flock's souls. It is their duty to watch for deviancy and ensure that heretical belief is purged wherever it lurks. A truly pious Preacher may rise to become a Pontifex, whose authority extends over several parishes and their Preachers. The responsibilities of a Pontifex are diverse and can encompass the protection and ministration of routes of pilgrimage, the consideration of beatitudes and recommendation of canonisation to the holy synods. The priests called Confessors are the booming voices of the Ecclesiarchy, exalting the faithful to deeds of penitence, fervour and righteousness. Confessors are not charged with the ministrations of a diocese, but rather roam the Imperium at-will wherever the hand of the God-Emperor calls them. Under the spell of a Confessor a city can burn at the hands of its own citizens, armies may jubilantly throw themselves into the waiting guns of an enemies' hands and Heretics flee, fearing their holy wrath.

Cult Mechanicus

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Sigil of the Cult Mechanicus

Technology and its mysteries are the preserve of the followers of the Machine God, the Tech-priests of the Cult Mechanicus. For they believe that machines are imbued with a life-force of their own, a soul granted to them by the Machine God who governs the universe -- a will and a personality. The more ancient a piece of technology, the greater reverence it will elicit from these robed followers, who will spend many hours anointing a machine with the correct unguents before pressing the sigils of activation to coax its animistic Machine Spirit into life. The God-Emperor of Mankind is the Omnissiah in this view, the physical embodiment of the Machine God in realspace.

A machine that is both old and complicated is given the same status by the Tech-priests as the Ecclesiarchy would give a major Imperial Saint, for many of the systems on these machines are irreplaceable, their secrets lost to time. Among the greatest of such machines are the vast Battleships of the Imperial Navy, or the super-heavy Titan war machines, whom the Tech-priests call "god-engines.". But the Tech-priests will also lavish their attention upon an antique Lasgun or prognosticator and will spend much time trying to understand the intricacies of a device's workings. All machines though, no matter what their pedigree, are treated as living things by the Tech-priests and they will treat all with reverence, for all are gifts from the long-lost past, knowledge of their function handed on through time only by the beneficence of the Machine God. Woe betide any man who fails to treat his weapon with respect or hurls abuses at his desktop logicator within the range of the cybernetically-enhanced senses of a Tech-priest.

Paradoxically, true machine intelligences, Silica Animus, are held to be anathema by the Tech-priests, for they view these as soulless automata, spiritless things cast into the galaxy to confound the will of the Machine God. Shrouded in myth and legend, these abominations, the so-called "Men of Iron," are rumoured to have originated during the Dark Age of Technology and to have caused immense damage to the interstellar Human civilisation that had existed before the Age of Strife brought it low. Supposedly pathologically dangerous, an Inquisitor may encounter them, although rarely, in the course of his duties. Should they learn of these creations, the Tech-priests will hunt them down, investigate them and then destroy them. Only properly sanctioned digital logic engines and Cogitators, those deemed to have a spirit gifted them by the Omnissiah (and to lack true sentience), are allowed to persist.

The Imperial Demesne

Imperius Dominatus-4th Edition

Imperius Dominatus, a stellar map of the territory of the Imperium of Man in the 41st Millennium before the birth of the Great Rift.

The territory of the Imperium is defined by the reach of the psychic beacon of the Astronomican, which has a range of approximately 50,000 light years. The Imperium proper could thus be thought of as a sphere whose center lies at Terra's Sol System, and whose radius is about 50,000 light years wide. However, as a practical matter, agents and agencies of the Imperium (along with "unofficial" representatives of the Imperium -- such as Rogue Traders -- who often work in tandem with the goals of the Imperium) carry on its affairs and expand its influence beyond that limit. The disparate and widespread nature of Imperial territory, with its millions of star systems and worlds, means that a strongly centralised government would be unfeasible.

Wh40k starmap

The Milky Way Galaxy in the 41st Millennium before the birth of the Great Rift.

The Imperium encompasses countless worlds. No one has ever been able to map them and no one can even say how many there are. Entire departments of the Adeptus Administratum are devoted to cataloguing the worlds in the Emperor's domains, a never-ending task, for it is in a state of eternal flux. Furthermore, the Adeptus Terra holds that the whole Human species and the entire galaxy are under the Emperor's rule -- the Imperium has a manifest destiny to unite Mankind, impose its laws on every Human world and destroy all alien life. The true scope of the Imperium is, therefore, the entire galaxy, though this is far from actuality. The Imperium jealously guards its territory whenever it can but its sheer size means that it cannot react to every circumstance. Many planets live and die alone, with only the truly great threats commanding the attention of the Adeptus Terra. Worlds are frequently lost to aliens, rebellion or disasters, with news of their destruction sometimes taking centuries to reach Terra. The Imperium's borders undergo constant change, with new worlds discovered, conquered or colonised and old ones lost to xenos attack, Exterminatus or even to the Warp.


The Milky Way Galaxy after ca. 999.M41 in the Era Indomitus displaying both the Cicatrix Maledictum and the territory of the Imperium Nihilus cut off from the Emperor's light during the Noctis Aeterna. The half of the Imperium on the Terran side of the Great Rift is known as the Imperium Sanctus.

The Imperium of Man divides the galaxy into five administrative zones called Segmentae Majoris, which include the:

  • Segmentum Obscurus, a region to the galactic "north" of Terra that has been heavily fortified by the Imperial Navy and the Astra Militarum due to the dangers posed by this Segmentum's most infamous element, the Eye of Terror. This is a vast Warp rift where the Immaterium actually intrudes upon material space -- as do the Chaos Space Marine Traitor Legions and the daemons of the Ruinous Powers themselves.
  • Segmentum Ultima, the largest province of all in the Imperium, located to the galactic "east" of Terra; its furthest extents are beyond even the range of the Astronomican in Wilderness Space still unexplored by Humanity.

The Segmentae are the primary administrative divisions of the Imperium. Each is divided into sectors, which are areas of three-dimensional space. The sectors in turn consist of sub-sectors, each containing a number of individual star systems. These spatial divisions and subdivisions are also levels of the administrative hierarchy.

Each Segmentum Governor (or Segmentum Commander, the term used when the governor is acting in his military capacity) oversees his Sector Governors (or Sector Commanders), who in turn oversee Sub-sector Governors (or Sub-sector Commanders), who in their turn oversee the individual Planetary Governors, who are also known as Imperial Commanders. The higher ranks in this administrative system are usually combined with a basic planetary governorship as well as interstellar duties. Each of these governors is usually a member of the Imperial nobility and it is rare, but not impossible, for a man or woman born in the lowest ranks of Imperial society to rise to the rank of an Imperial Governor on his or her own merits or abilities rather than inherit the role. This neo-feudal system is the means by which the Imperium maintains control of the separate planets that comprise it.

Planetary Administration

Because of the distances involved and the unstable nature of Warp communication, Planetary Governors generally operate very autonomously. This allows quite a lot of variation in the regional governments of the Imperium. Some governorships are hereditary, but it is also possible for a planet to have an elected Planetary Governor, a tyrant Governor who rules solely by force of his personal arms, or anything in between. So long as the Governor fulfills his duties to the broader Imperium, his rule will generally be accepted by the higher authorities with little or no interference.

A rare few Planetary Governors preside over Feral or Feudal Worlds where the Imperium has not, for whatever reason, seen fit to introduce advanced technology. These Governors are often isolated from their subjects, sometimes even living on orbital installations, only interfering to control mutation, Chaos incursions, Ork invasions and rogue psykers, as well as to collect the modest tithes in men for the Astra Militarum and psykers that these planets provide. The Imperial duties of a Planetary Governor include paying the planetary tithe to the Administratum, controlling psykers, mutation and heresy among the population, defending the planet and putting down rebellions against the local government (and thus against the Imperium). A serious responsibility for a Planetary Governor is the maintenance of an adequate local military force capable of defending the planet in the event of an invasion. The Planetary Defence Forces (PDF) are expected to defeat attacks from minor foes, and in the case of major invasions to hold out until reinforcements arrive, which could take a period of solar months, standard years or even solar decades.

A relatively small number of Imperial worlds are not ruled by a Planetary Governor, but are directly overseen by an alternate organisation such as the Adeptus Terra, the Ecclesiarchy, an Imperial Commander of the Astra Militarum or a Chapter of the Adeptus Astartes. These planets include the Forge Worlds of the Adeptus Mechanicus, whose inhabitants toil without pause to manufacture the weapons of the Emperor's armies (including Mars, Gryphonne IV and Fortis Binary), the Cardinal Worlds of the Ecclesiarchy, which are given entirely over to education of the priesthood and worship of the Emperor (Ignatius Cardinal, Ophelia VII), and the Space Marine Chapter homeworlds, such as Fenris, Macragge, Baal, or Medusa.

Just as the environments and cultures of Imperial worlds vary immensely, so too does the way they are governed. The Imperium allows most of its worlds to govern themselves, using whatever method of government the population gravitates towards or was the traditional form of rule. Some are hereditary monarchies, others are ruled by aristocracies or warlords. Some are ruled by elected parliaments, while on others power is given to whoever can pay for it. On some worlds these are the same thing. Upon other planets, such things as democracy, free choice and even individual civil rights are present, though these worlds are few and far between. Some worlds are administered directly by the various Adepta, such as Agri-worlds run by the Administratum or Cardinal Worlds ruled by the Ecclesiarchy. Whilst the individual nation-states, city-states, tribes, corporations, hegemonies, peoples’ work collectives, and so on, may have their own various leaders, the Adeptus Terra will always look to one person to fulfil the planet's Imperial Tithe and obligations to the Imperium. Titles for this governor vary from planet to planet. In some cases the person judged responsible for the Imperial Tithe may not even be aware that this is the case until too late. Certainly, more than one titular head of state has discovered this upon rejoining the Imperium after a period of isolation through Warp Storm, war or other calamity.

All Imperial Governors are expected to recognise the authority of the Imperium and the Emperor and to uphold His laws. These responsibilities include aiding the agents of the Adeptus Arbites and the Inquisition, as well as arranging the allotted tithes for the Administratum. Governors are also expected to yield psykers up to the Black Ships of the Inquisition when required and to keep the population free of mutants, Chaos Cultists, Heretics, political radicals and witches. In practice, some planets escape from these duties with relative ease, whilst others are placed under seemingly tyrannical restrictions. Due to the sheer size of the Imperium and the unpredictability of travel through the Warp, there are many occasions where the Administratum never manages to extract its levy, or the Black Ships never arrive at the appointed time to take psychic individuals away. Planets can be isolated for generations and it is not unusual to encounter worlds where the Imperial Tithe has been all but forgotten. Certainly the scribes of the Prol System have, in their vast libraries, several accounts of Administratum Logisters arriving at worlds lost for centuries, only to discover their yearly tithe burning on vast pyres as the natives offer their dues up to the sky.

In some cases, a group of planets might have enough contact with one another to form political alliances and even minor interstellar empires. Other clusters of worlds might be connected by huge corporations, the powers of hereditary nobles, religious leaders or other such ties. In such cases, Planetary Governors must not only tend to the needs of the Imperium but also the whims of these local power blocs.

Human Variability

The peoples of the Imperium vary in their form and appearances just as their homeworlds do. Whilst there is a generally agreed baseline Human standard, consisting of four limbs, one head, twenty digits and so on, the local environment and genetic stock have caused all manner of interesting anomalies, evolutionary adaptations and fashions. These differences are usually cosmetic in effect; however, the more radical alterations walk the line between accepted variation and outright mutation. It is a subject of intense debate amongst some Inquisitors, and indeed the priests of the Ecclesiarchy, on what it is to be Human and therefore accepted into the Imperium.

Certain planets will betray their colonial origins with the appearance of their peoples -- perhaps a particular type of nose or skin colour will be dominant. Others will have clear tribal divisions. Some populations will possess unusual adaptations as a consequence of their local environment. The folk of the Agri-world Dreah, for example, have a grey skin, hair and eye tone, which exactly matches the flora, fauna, sky and waters of their notoriously dull planet. Some cultures may impose certain ideals of beauty that drastically alter the looks of their peoples. Certainly, many strange and terrible gangs of Underhivers have been discovered, clad in hyper-fashionable armour, sporting glowing Electoos, skull studs, gang tribal mutilations and shiv scars with pride.

To some extent a similar appearance and culture binds the people of a planet together into a common stock. Usually speaking, citizens of the Imperium will prefer to spend their time with fellow natives of their world. That said, however, Mankind has ever been titillated by the exotic, so friendship, love affairs and even children with off-worlders is not unknown on planets with a culture that legitimises such travel.


The Imperial Creed maintains that all of Humanity must be brought and kept within the Imperium where men and women can benefit from the rule of the Emperor. Several Imperial organisations are permanently occupied with suppressing any possibility of rebellion before it has a chance of developing. The common worship of the God-Emperor holds Mankind together and instills loyalty towards the Imperium. Rebellions and uprisings on Imperial planets nonetheless remain a constant problem. The nature and causes of a rebellion can fall into several categories: the government of an Imperial world may decide to secede from the Imperium; a popular uprising may attempt to overthrow the local Imperial government; in the most insidious of cases the rebellion may be brought about by alien or Chaos influence. In the more prosaic cases however, a new planetary government established through rebellion is not necessarily opposed by the Imperium, so long as it accedes fully to Imperial authority and pays its tithes to Terra. Besides the pursuit of outright war, there are many ways a rebellious world may be brought back into the Imperium. With the existence of its more secretive organs like the Inquisition, the Imperium is fully capable of carrying out covert methods of restoring Imperial rule, including assassination, popular agitation, economic sabotage and terrorism. Sometimes a rebellion can be subdued by the removal of a single individual. Pro-Imperial groups or other anti-government forces can be infiltrated or supported as required.

Great Rift

The Fall of Cadia and its ancient pylons during the 13th Black Crusade, the sundering of Craftworld Biel-Tan during the Battle of Biel-Tan and the partial awakening of Ynnead, the Aeldari god of the dead, the breaking of the Amethal Daemon cage during the Diamor Campaign, Magnus the Red's vengeance on Fenris during the Siege of the Fenris System and the return of the Planet of the Sorcerers to realspace -- these and dozens of other pivotal events fractured the stuff of reality as the 41st Millennium raced towards its bloody conclusion.

Any or all might have been the final blow that broke the fault lines wide open and unleashed the Great Rift upon the galaxy. Known also as the Cicatrix Maledictum in High Gothic to the Imperium, Gork's Grin to the Orks, the Dathedian to the Aeldari and countless other names weighted with dread and mythological symbolism, it has changed the face of the galaxy forever, stretching from the Eye of Terror in the galactic west to the Hadex Anomaly in the east.

Upon its opening the rift unleashed a tsunami of ferocious empyric energy and supernatural darkness that temporarily cut Humanity off from the light and psychic protection of the Astronomican that was known to the Imperium as the Noctis Aeterna, and this event alone claimed countless worlds, fleets and armies. Though that shadow has receded in much of the galaxy, still the rift roils and spreads, devouring entire species with its unnatural fury.

Imperium Sanctus

Though certain that the opening of the Great Rift in the Era Indomitus was the work of foul Heretics, few in the Imperium know the truth of how or why this catastrophic chain of Warp storms erupted across the galaxy. It is clear only that the Imperium is split apart, torn in two by a roiling belt of malevolent empyric energy that has left the Emperor's realm divided as never before.

The vast galactic region known as the Imperium Sanctus is the half of Humanity's realm that fared better in the wake of the Great Rift's opening. Of course, in this time of nightmares "better" is a comparative term. Consisting of the Segmentum Pacificus, Segmentum Tempestus and Segmentum Solar, and parts of both Segmentum Obscurus and Segmentum Ultima, the Imperium Sanctus has Holy Terra at its heart. From here flows the psychic light of the Astronomican, a magnificent golden beacon that shines through the madness of Warpspace to act as a guide for voidships navigating that perilous realm.

Throughout this immense region of the galaxy, Imperial worlds of every sort raise their tithes of military manpower and vital resources, sending them forth to bolster the armies of the Astra Militarum and feed the never-ending hunger of Humanity's stellar empire. Space Marine strike forces surge from one war zone to the next, battling the deadliest threats to the Emperor's realm while vast Imperial Navy battlefleets engage in blistering void wars against invasion swarms of every sort.

Crusades of the Sisters of Battle bear the word of the Ecclesiarchy into the fiery heart of battle, purging Heretics against the Imperial Creed wherever they are found. Countless Imperial agents work the Emperor's will -- overtly or secretly -- throughout the Imperium Sanctus, while upon Mars and her countless subsidiary Forge Worlds the Tech-priests of the Adeptus Mechanicus horde the arcane secrets of the Omnissiah; they use this dimly understood lore to fashion the technologies and weapons Humanity's armies require to battle their foes.

This is not to say that the Imperium Sanctus is a well-oiled machine. Only astropathic communication can bridge the vast distances between Imperial worlds; passing from one straining Warp-sensitive mind to another through the treacherous dimension of the Immaterium, this process of psychic messaging is heavy with symbolism, vagary and inaccuracy.

Worse still is the very monolithic bureaucracy by which the Imperium Sanctus is governed; mindless and uncaring, glacially slow, the machineries of administration grind all into dust. Millennia of historical learning are lost amidst dusty catacombs, sealed away behind barriers of religious censure. Response times to crises can often be measured in standard years, solar decades, even centuries. To this vast bureaucratic machine the fates of entire worlds barely register, while individual lives mean less than nothing. The living beings of the Imperium are but grist for its ever turning mill, a resource no different to the promethium that fuels its engines, the steel and adamantium that armours its warriors and war engines and the protein gruel that feeds its armies in the field.

Most of the men and women who populate this sprawling empire are born, live their lives of toil and fear and eventually die from hardship, malnutrition, exhaustion or some barely remarked upon industrial accident without ever having seen an alien, a Heretic, nor even a warrior of Humanity's armies; crushed down by the oppressive dictatorial rule of Imperial law, and comforted in whatever desperate fashion by faith in the Imperial Cult, every one of them has served their part in Mankind's galactic war just as does a bullet fired from a gun or a blade driven into an enemy's guts. Truly, only those who take to the stars to war or conquer in the Emperor's name stand any chance of seeing more of existence than this, and even then much of what they witness is invariably horrific.

For all its nihilistic misery and soulless oppression, the Imperium Sanctus continues to grind onwards, its sheer weight and momentum carrying it forwards through tragedies unnumbered and hardships untold. This is Humanity's every effort turned wholesale to sustaining total war, all the while praying to the Emperor that one day this nightmare may finally end.

Imperium Nihilus

Vast tracts of Imperial space lie beyond the roiling Warp storms that make up the Great Rift. Cut off from all but the most determined aid, blind to the Astronomican's light and beset upon all sifes by legions of nightmarish foes, the worlds of the Imperium Nihilus, the "Dark Imperium," must look to their own survival, by whatever horrific means necessary.

The region of space known as the Imperium Nihilus is cut off from Terra's light by the Warp storms of the Great Rift. Not only is the light of the Astronomican obscured by these raging tempests, but there are also only two comparatively stable channels through which Imperial fleets are able to cross the storm front. Even these shuddering gauntlets are haunted by empyric phantasms and piratical wolf packs, but they are at least safer than the narrow passages that open sporadically between the storm belts only to sweep shut like a monster's jaws upon those brave or desperate enough to dare the crossing.

Thus severed from the rest of the Emperor's realm, each world in the Imperium Nihilus must stand alone amidst the darkness. Many fell during the first nightmarish days of the Noctis Aeterna, when shock waves of psychic upheaval lashed the galaxy in the wake of the rift's opening. Planets and their populations were annihilated or twisted beyond recognition as Warp storms engulfed them. Hordes of Daemons spilled from rents in the fabric of reality to butcher and torment all before them. Heretical cults arose, prophesying the end of all things and whipping formerly loyal citizens into a murderous frenzy. Rampant mutation ran rife, abominations were spawned from the darkest nightmares of Human minds and entire populations turned on one another in self-destructive storms of violence and cannibalism.

Other Imperial worlds held out. Fortresses rallied their garrisons, readied their weapons and drove back attackers from within and without. Hardy Agri-worlders formed defence militias, vanishing into the wilds and fighting guerilla wars against alien invaders. Industrial Worlds drafted every man, woman and child to churn out endless streams of materiel, hurling wave upon wave of conscripted soldiery into the teeth of terrors from beyond the stars.

Even still, for many worlds death might have been the kinder fate. The Immaterium roils and churns, making Warp travel catastrophically perilous. Forced to wrestle with spiteful empyric tides, wildly erratic destination flux and dramatic temporal distortion, Imperial voidships in the Imperium Nihilus can risk only the shortest Warp jumps, meaning that not only is travel through the Imperium Nihilus terrifyingly dangerous, but it must also proceed at a virtual crawl. Interplanetary communication, too, has been almost entirely stifled; forcing an astrotelepathic message across the Imperium Nihilus requires herculean and often fatal effort, and even those missives that do make it to their intended recipients arrive in the form of recurring nightmares.

Many worlds are wholly isolated, more than one population believing themselves the only surviving bastion of Human ciilisation in the galaxy. Many planetary governors, military commanders and religious leaders have been forced to make terrible choices and commit monstrous deeds in order to keep the lights of civilisation burning upon the worlds they rule. Plagues of mutation, madness and supernatural disease blossom while landscapes warp and change beneath baleful skies. Malefic entities manifest seemingly at will to prey upon the unwary, while simple despair stalks every Human soul. And always the Great Rift blazons itself across the firmament, corrupting all that its noxious light touches.

Though the Human territories within the Imperium Nihilus are crippled, the same is not true of their enemies. Some xenos species possess alternate methods -- be they technological, biological or seemingly sorcerous -- by which they can traverse the stars while bypassing the Warp altogether. Others revel in the madness that has been unleashed, joyriding the currents of empyric madness wherever fate wills and falling in howling tides upon whatever worlds lie in their path.

That which blights Imperial worlds, fleets and armies serves only to aid the worshippers of the Dark Gods. Even as it churns in madness, the Warp sweeps these Heretics and Traitors along on favourable tides, more often than not bearing them to their destinations swiftly, if not safely. Surges of immaterial energies allow renegade psykers to enact unspeakable rituals that drag entire worlds into damnation or translocate them into the hellish heart of the Warp. Ancient and terrible beings not seen abroad in millennia feed off the raw energies of unbridled chaos, gathering the strength to force their way through the veil and fall upon Humanity with howls of glee. Everywhere hope fails.

Still the Loyalist worlds of the Imperium Nihilus fight on, shoring up their faltering hope with unbridled hate. For every star system swallowed by the darkness, a crusade blazes a trail across the stars to relieve the desperate defence of another. Space Marine Chapter planets, Inquisitorial fortresses and Adepta Sororitas preceptories shine as bright beacons of defiance amidst the shadows. Knight Worlds light their watch fires and weather the storm, just as they did during the dread millennia of Old Night.

Meanwhile, daring Rogue Traders, dogged Adeptus Mechanicus Explorator fleets and courageous Imperial Navy flotillas brave the tumult of the Immaterium to bring hope to lost worlds or claim new colonies for Mankind. Perhaps the end of the galaxy draws nigh. Perhaps the darkness of the Imperium Nihilus will spread like a funeral shroud over all of Humanity's endeavours. However, while faith continues to burn strong in the hearts of men and women, the defenders of the Imperium will not give in.

Perhaps this hope has been rewarded. When the Indomitus Crusade of Roboute Guilliman arrived to aid the Blood Angels Chapter and their successors against the horrors of Hive Fleet Leviathan during the Devastation of Baal, Guilliman appointed the Blood Angels' Commander Dante as the new regent of Imperium Nihilus. All the sons of Sanguinius now fight to reclaim the Dark Imperium from those who would defy the will of the Emperor.

Imperial Languages

Low Gothic is the common tongue of the Imperium, spoken on most Imperial planets as a first or second language. Imperial worlds have inevitably developed their own, often highly variant, dialects of Low Gothic over time. High Gothic (fictionally represented as a form of Latinised English) dates from the last time Humanity was united across interstellar distances in an ancient confederation that existed during the Dark Age of Technology (long before the Age of the Imperium), and is used solely as a hieratic tongue in the 41st Millennium by the divisions of the Adeptus Terra, the Inquisition and the Ecclesiarchy. High Gothic is the language that was spoken by the people of Terra at the time of the Great Crusade and the Horus Heresy and is considered a sacred language because it was the tongue of the Emperor Himself.

Low Gothic (also called "Imperial Gothic" or simply "Gothic") is the "official" language of the Imperium, the everyday tongue of its adepts and of Terra. Most worlds have been a part of the Imperium for long enough to have adopted Low Gothic as a universal tongue but there are still a great many Feral Worlds on which Imperial Gothic is not spoken.

Inevitably, dialects of Gothic differ from world to world and can be mutually unintelligible. Older planets frequently maintain archaic tongues of their own, to the extent that ruling aristocracies might only know enough Low Gothic to be sworn into their Imperial offices. For highly formal matters, the Adeptus Terra use High Gothic, the related precursor language of Imperial Low Gothic. Many Ecclesiarchy rituals, Administratum edicts and Imperial charters use this ancient and venerable language.

Psykers in the Imperium

Humans with psychic powers, known colloquially as "psykers," who possess abilities ranging from telepathy to pyrokenesis, have existed since the dawn of Mankind's existence as a species during the Paleolithic Age on Old Earth, but their position in the Imperium is an uncomfortable one at best.

An untrained psyker is an unguarded gateway to the Warp, through which psychic predators like Daemons and Enslavers can enter realspace and wreak havoc. It is said that whole worlds have been lost to hideous monsters of the Empyrean, while rogue psykers have committed horrible crimes with their powers or led dangerous and destructive cults.

On some worlds all psykers are tried as "witches," subjected to tortuous ordeals and burned at the stake when their inevitable guilt is proven. Imperial law requires all worlds to monitor its psykers and subject them for testing by the Adeptus Astra Telepathica. Those who are strong enough to withstand the perils of the Warp are forced to endure the soul-binding and are trained to serve the Imperium as Sanctioned Psykers. Those who are too weak are taken away by the Black Ships and never seen again, their lives used to maintain the Emperor's strength within the Warp and power the Astronomican.

Travel in the Imperium

Interstellar travel between the worlds of the Imperium is rare and dangerous. The vast majority of civilians will never know the roaring tedium of shuttle flight, the sickening plummet of a Drop Pod or the unnerving silence of deep space. Given the huge size of the Imperium, it is impossible to cross it in the fleeting span of time given to ordinary men. Colonists, pilgrims and refugees spend many generations in the vastness of space, and many starships never survive the vagaries of travel to reach their destination.

Sub-Light Travel

Used mostly for journeys between planets or closely neighbouring star systems, sub-light travel involves speeds that confound mortal imagination and yet are still nothing when measured against the sheer size of the galaxy. Those attempting to use slower-than-light drives to travel any appreciable distance condemn themselves and their descendants to a shipboard life, endlessly whittling away the Terran years until they arrive at the distant star they set out to reach. The average Imperial citizen is unlikely to experience slower-than-light space travel. Even those individuals living within a star system with plentiful voidships for interplanetary travel are likely to prefer the world of their birth over distant places with strange customs, odd food and "funny-looking" people.

In many places, space travel is reserved for the privileged few who can afford to maintain the rituals, priests and shrines that such voidcraft require, as well as the vast cost of the starships themselves. Tech-priests do what they can to sate the Machine Spirits of these spacecraft, but often even their unfathomable lore is not enough to prevent these temperamental ships from venting their rage (and oxygen) to the detriment of passengers. Sheer odds dictate that sooner or later those that frequently travel in ships between planets will experience such a disaster. Those worlds that have not lost the art of creating and maintaining slower-than-light starships jealously guard their arcane craft. This reluctance to share their guild secrets ensures the reliability and price of their vessels but also robs others of vital information required to placate their own craft. Institutions such as the Imperial Navy, the Inquisition and various Adepta have access to much better-quality vessels, maintained with religious awe and reverence by countless generations of the Adeptus Mechanicus.

Warp Travel

"For the Warp is a strange and terrible place. You might as well throw a traveller into a sea of sharks and tell him to swim home as send him through the Warp unprotected. Better it is not to let common man travel through the stars. Better still, let him now know such a thing is feasible."

— Fra Safrane, 5th Aide to Navigator Da'el. Comment made prior to the departure of the second mission to search for the missing freighter Pride of Angelus

To move any appreciable distance within the Imperium, voyagers must make use of Warp travel. This method of faster-than-light travel is rare, expensive and dangerous, as it requires the use of the unpredictable realm known as the Warp, or the Immaterium. Vessels equipped with a functional Warp-Drive are able to translate themselves into this other dimension of being that coexists with the material universe by generating an envelope of protective Gellar Fields. The Warp-Drive "bends" the starship through the veil of realspace into the Immaterium. Once within this strange hyperdimensional realm, the starship is able to ride the currents and eddies that flow within the Warp, frequently dropping back into realspace to check its positioning.

The Immaterium is a bizarre and contradictory place, entirely unnatural to Mankind or any being of realspace. Looking upon the Warp unprotected causes madness and Chaos corruption, and thus is greatly feared by almost everyone in the Imperium. Dimensions, colours, forces and emotions operate entirely differently within the Warp's embrace, and this can drive even the most thick-headed crewman insane. Psykers of course, find such travel even more disturbing as their mystical senses are able to comprehend much more of the Immaterium and the foul creatures that dwell within it. Those that travel through the Warp emerge to discover another of its disconcerting effects. Time does not operate normally within this other realm and so travellers can emerge to discover that Terran centuries have passed in realspace since they started their journey, that they have merely been absent for a few solar seconds, or have even arrived before they left. Even skilled Navigators cannot predict how much time will be lost, gained or repeated over the course of a journey. Those that embark upon Warp travel know that they will probably never return home, or that if they do so they will find it so changed that it is unrecognisable. When two or more captains of starships meet, they invariably trade dates, attempting to reconstruct the time they are missing or have gained. Needless to say, Warp travel is not embarked upon lightly.

The Warp is occasionally prone to great turbulence or storms of activity. These strike at random and last for an unpredictable amount of time. Whilst these Warp Storms rage, any vessels within are tossed about on roiling currents, sometimes being spat out at random locations. Other ships simply become trapped, unable to translate back into realspace, cursed to an eternity upon the waves of the Warp. These storms disrupt communication across the Imperium and can sometimes herald a great disaster within realspace, as they did during the Age of Strife before the birth of the Chaos God Slaanesh during the Fall of the Eldar.

Imperial Communications

Just as travel within the Imperium is a complicated and inexact science, so too is the business of exchanging messages between the many and varied planets that make up the Imperium. Planetary communications systems such as radio-based Vox-casters, hardwired telegraph and telephony lines and the more advanced Vox-communicators suffice to pass messages amongst the nations of a world, yet have almost no use beyond the bounds of the planet's surface. Such devices can require many Terran years for their signal to reach even the nearest planet of a star system and have no surety of even being detected when they arrive. The perils of travel ensure that Human or servitor messengers are just as unreliable and potentially as slow as radio or other energy wave communications.

The Imperium is forced to rely upon communication by psychic, or astro-telepathic means. Astropaths communicate with symbols and iconic images, projecting these messages through vast distances of space by means of psychic power drawn from the Warp. This process is usually exhausting and requires ritual and focus in order to keep the psyker in the right frame of mind. These can take a wide variety of forms, such as use of the Emperor's Tarot, vision quests, automatic writing, trances, séances and the like. The Gaolist Astropaths of Hredin for example, spend many years etching their messages onto painstakingly illuminated sheets of iron and then destroy the work of art upon a massive grinding wheel when they are ready to transmit the information. The pain of annihilating a much-loved labour is said to produce psychic messages of unparalleled clarity.

These messages are received by fellow Astropaths in various ways. Some appear as vague and troubling dreams, whilst others appear as visions or mystic portents. Others appear within whatever ritual method or divination technique the receiving psyker happens to practise. Thus warning of an Ork invasion might appear as a glistening imperfection in fish entrails, a looming cloud of smoke, bleeding orifices or a worrying combination of runes or sigils within a holographic matrix. Astropathic messages must not only be transmitted from one Astropath to another but decoded at the other end. Each Astropath employs slightly different symbols and each has a preferred style or "flavour." Some messages take solar weeks of poring over tomes of augurs and symbolism before they can be reconstructed, though the best Astropaths can do this word for word. Some remain a mystery forever. Some messages are received by Astropaths at entirely the wrong end of the galaxy and must be passed on to others who are nearer the place in question.

Some messages simply do not get to their intended recipient or are drastically misinterpreted along the way. In addition, there are too few Astropaths. Most worlds, especially those with small populations or on the fringes of the Imperium, have no Astropaths at all, and must rely on the infrequent visits of passing Chartist ships or Administratum census-takers to make contact with the outside galaxy at all. For this reason the Adeptus Terra cannot react quickly to every event in the Imperium, even when an event occurs that is great enough to attract the notice of the vast and ponderous Imperial bureaucracy. On most worlds, the Imperium feels very far away.

Imperial Calendar

The Imperium of Man originally used a special Imperial Dating System derived from the original Gregorian Calendar of Old Earth that denotes the current year by the notation (year of the millennium).M(number of the millennium). For example, the year 40,999 A.D. would be represented as 999.M41, while 41,002 would be 002.M42 and the year 2021 would be 021.M3. However, the year 41,000 A.D. would be 000.M41, since the new millennium starts at the year 001 and has no Year 0.

In the wake of the resurrection of the Primarch Roboute Guilliman and his return to the position of lord commander of the Imperium and Imperial Regent in ca. 999.M41, he discovered that the Imperial Calendar had become degraded by both dogmatic adherence and thoughtless revisionism. Various rival dating systems had evolved from the Imperial Standard, making a true, accurate chronicle of the galaxy almost impossible to construct.

As the Indomitus Crusade's first phase drew to a close approximately twelve standard years into what would once have been designated the 42nd Millennium, Guilliman calculated the current year by the five main factional variants of the Imperial Calendar to be anywhere between the early 41st Millennium and an entire millennium later, and that was leaving out the numerous lesser, more heretical interpretations. As a result, most dates given in the 41st Millennium should be considered unreliable or approximations at best in relation to the period of the Great Crusade and the Horus Heresy, and many have argued that the Imperium is still in the midst of the 41st Millennium.

Following the birth of the Great Rift and the start of the Era Indomitus, temporal anomalies spread across the galaxy making the use of a universal dating system extremely difficult as different Imperial worlds began to experience the passage of time at different subjective rates.

A new, more localised dating system came into existence that was different for each settled world or star system. It used the birth of the Great Rift as the standard event from which all time was calculated, either before or after its creation.

Imperial Currency

The economic systems in existence across Imperial space vary from world to world and their levels of technological progression and so there is no standardised financial system or currency in use across the entire Imperium. On more primitive Feral and Feudal Worlds, there may be no system more complex than bartering or the exchange of a basic, precious metal-based currency.

However, most civilised worlds that have achieved the standard level of Imperial technology make use of some form of fiat currency for all economic transactions which is often digital or electronic in form. The names of these currencies vary as wildly as the Human cultures that employ them. Some are used only on individual worlds or their surrounding sub-sectors, while on others the currency may be accepted on a sector-wide or even multi-sector basis.

For example, the Imperial currency of the Calixis Sector and many of the surrounding regions such as the Koronus Expanse is known as the "Throne Gelt", embodied in the form of metallic coins known simply as "thrones," a reference to the Emperor's Golden Throne. This currency, like most in the Imperium, is a fiat currency based on the value of the local region's Imperial Tithes. There are also precious shell tokens or coins of rare or strategic metals that are accepted as legal tender on all of the civilised Imperial worlds of that sector. Thrones can also be dispersed in electronic form as payment, usually by using a data-slate.

Threats to the Imperium

Despite being the largest empire that Humanity has ever known, many planets within the Imperium feel isolated and alone in the deep void of space. Across all the peoples and planets of the Imperium, fear gnaws away at the psyche, worming mistrust and desperate faith into the conscious and unconscious mind. Time and again the universe has proved itself an uncaring and frightening place deeply hostile to the survival of Humanity. People fight one another, the Warp rages, xenos attack and worlds die. The people of the Imperium watch their neighbours for signs of heresy and witchery. Mankind prays to the Emperor to protect them from the woes of the universe, of which there are many.

Dark Gods and Daemons

Time and again throughout history, the minds of Man have proven fertile soil for the seeds of corruption by Chaos. There are certain dark powers abroad in the universe that seduce the weak and foolish into their damnable service. These ageless beings, their names unspeakable, prey upon Mankind's needs and desires. With honeyed words, forbidden knowledge, bloody rites and festering secrets they lure Humanity to become their slaves. Some within the Imperium choose to worship these Daemon Gods. The ways of these Chaos Cults are many. Some meet in clandestine rituals of sacrifice and incantation. Others are foolish scholars, meddling with powers beyond their ken. Others still are organisations, companies or political groups drunk with power gained through pacts with unspeakable creatures of the Warp. Perhaps worst of all are the instances of entire worlds that worship the Chaos Gods through ignorance or choice. All of these profane cultists invite ruin upon themselves, the Imperium and Humanity. The Adeptus Terra, Planetary Governors and the Inquisition all watch for these disciples of Chaos, for the inevitable consequence of their meddling is pain, disaster and bloodshed. The ordinary peoples of the Imperium rightly fear these cults and their malevolent masters. On many worlds an undercurrent of paranoia, suspicion and fear of Chaos Cultists is the norm.

The very existence of such fell beings as the daemons of the Warp is a terrible secret to most citizens of the Imperium, as the Imperium's rulers believe such truths must be hidden from the minds of those who would fall prey to them. A daemon is a Warp entity, a terrible creature of thought and psychic energy brought forth into existence by the twisted needs of sentient beings, or at least so the high masters of the Ordo Malleus say. To even think of them is to invite their attention and only the steeliest mind, the most powerful faith in the God-Emperor, is enough to overcome their utter, monstrous evil. Inconceivable as it may seem, there are those who would consort with the daemon, for they whisper dark things in the night to those who would listen and make many promises of temporal or eternal power. They can be brought forth willingly, by the witch or by certain arcane sorceries, or they may try to force a way through into realspace through the unsuspecting portal of an untrained psyker's mind. However they become incarnate, if they achieve their goal, just one daemon can bring ruination to all it encounters. One need not talk of the Night of Silence in Atraxian III's capital city, nor of the lost world of Abandoned Hope, which to this day is warded by the Inquisition, knowledge of its existence forbidden to all. Make no mistake, to face a daemon is to face damnation, to court a daemon is to embrace its dark masters.

Mutants and Witches

Various Mutants

Ordo Hereticus pict-file displaying a menagerie of mutants encountered by the forces of the Inquisition.

The degeneration of the holy Human form is one of the Ecclesiarchy's greatest concerns. Environmental pollution, deliberate genetic alteration, stellar radiation, alien diets and simple evolutionary adaptation have wrought manifold changes upon the genome and body of Man across his vast stellar empire. Some of these mutants have a standard, stable, morphological type and are tolerated by the authorities -- notable among them being the Abhuman Ogryns and the ancient and noble Navigators. But to find whole worlds where the Human population has no eyes due to never-ending darkness, or unusually long legs because of millennia of nomadic living, is not unusual. Whether these aberrant populations are declared acceptable or not is the business of the Adeptus Terra.

But mutation can also be a sign of the influence of the Ruinous Powers of Chaos. Just as they twist and destroy the minds and souls of Man, so too do they toy with his flesh, bending it into profane shapes, gifting strange abilities and creating monsters for their perverse amusement. Where such mutation is present, it is rightly abhorred. Few are willing to tolerate such an aberation within their midst and fear of mutants runs through the populations of many worlds, even those where such things have happened but once in a hundred generations. Perhaps worse still is the constant fear of becoming a mutant oneself. Many folk pray that should this worst of all things occur, they will have the strength to end their own lives, before the mob or the Inquisition does it for them.

Some poor fools are willing mutants, seeing the distortion of their flesh as a sign of favour from the Ruinous Powers. They seek out ways to gain more of these mutational "gifts," either by begging the Dark Gods for more of their touch or by doing their bidding in the hope of further reward. Others, more poignantly, claim innocence of any wrong doing or foul worship. Whatever the case, a mutant is a mutant and must be feared, hated and destroyed. This is but one of the many reasons Imperial citizens tend to be highly intolerant and many innocent men, upon finding themselves on a new world, have been murdered by a frenzied mob for merely appearing to be different.

The related question of witchcraft also exercises the minds of a great many of the Emperor's servants. Indeed, one whole arm of the Inquisition -- the Ordo Hereticus -- has the finding and destruction of these dangerous beings as one of its primary activities, and several other organisations exist to contain, exploit and control these Human psychics. It is said by a heretical few that Mankind stands upon the brink of a great evolutionary change in the species, that every standard year the incidence of psykers rises and that one day the entirety of Mankind will become a new, psychic race much like the Eldar.

True or not, the psykers of the Imperium are a double-edged sword. On the one hand, they enable the continued existence of the Imperium -- the Astropaths, the Navigators, Imperial Sanctioned Psykers, the savant Primaris Psykers of the Astra Militarum, the Librarians of the Space Marines, even the Emperor Himself -- these loyal, good and necessary servants of Mankind are psykers all. Yet they are few in number and for every mind that is strong enough to stand against the perils of the Warp, there are hundreds of others whose minor gifts, whether they seem a boon or a burden to the individual, are a clear danger to the worlds of Man. The employ of their talents can lead to intrusions into the physical universe by Warp entities or leave the individual open to manipulation by certain strains of perfidious xenos.

By far the most dangerous are the "witches," those who revel in their abilities and seek to use them in a personal quest for power. Alone, they can wreak untold havoc, intentionally or unintentionally. It is for this reason that, of all the threats from within, the populace of the Imperium fears the witch most. It is a hidden danger that can spring up unbidden even inside a man's own family, and parents dread the birth of a witch child above all things. All psykers must be given over to the appropriate Imperial body or be purified by death. Those psykers that appear to have evaded the tithe-men of the Black Ships, by accident or design, are guilty until proven innocent and the cleansing flame is their only fate.


"Fear The Alien. Hate The Alien. Kill The Alien."

The Imperial Infantryman's Uplifting Primer (Damocles Gulf Edition)
Various Xenos

The myriad forms of the xenos

The Imperial Cult teaches that it is Mankind's manifest destiny to rule this galaxy. The Ecclesiarchy holds that it is the Emperor's will that Humanity and Humanity alone will bestride the stars, and to that end most Imperial servants fervently bend their lives.

There are many other creatures in the galaxy, unclean creatures born of worlds far from the sacred soil of Terra, whose misbegotten forms are an insult to those who wear the shape decreed by the Lord of Man as fitting and right.

Some of these creatures are weak and harmless, and easily extirpated, their planets expropriated for the true masters of the stars, their memory expunged. But there are other, stronger alien races that would see the will of the Emperor foiled and Mankind cast down.

Among them are the savage greenskinned Orks, whose numberless multitudes plague the galaxy with their endless desire for war. Hulking creatures, bigger than a man, they are mindless, yet powerful and unafraid.

Elsewhere can be found the fickle Aeldari, those who cannot be trusted, beings similar in appearance to Humanity which extend the hand of friendship whilst clasping a dagger behind their back. Beware these fiends; their machineries of war are as swift and as deadly as their lying tongues.

Likewise the Tyranids, blasphemous monstrosities who reduce worlds to bare rocks in their feeding frenzy, their endless armies made up of hellspawned bio-constructs.

Other things dwell in the dark places of space -- the Hrud, whose very presence is poison to the rightful progression of time; the T'au, whose heretical technicians enslave technology to their grotesque ends with no thought for the proper rites; the Verminthiculians, wild alien mercenaries and reavers.

Yet, while the alien is legion, the Imperium claims that Humanity is always the stronger, and the warmongering of such xenos species is but the desperate savagery of those who know that their end draws near.

Heretics and Traitors

The Imperium is the only rightful authority of Mankind, as has been decreed by the Emperor, and His will, executed by the Adeptus Terra, is absolute. But Man has ever been a fractious and fickle creature and not all agree that the Emperor's rule is to be desired. Therefore the rule of Terra must, by necessity, be harsh. The size of the Imperium means the grip of its governance must be loose, and rebellion is only regarded to have taken place when one of the various Imperial Tithes goes unpaid. Worlds which rise up to shake off the benevolent hand of the Emperor fall into one of the following four categories:

  • Governmental Revolt: Occasionally the ruling body of an Imperial world might misguidedly decide that their planet would be far better off outside of the Imperium. They might not have been visited for a thousand Terran years or the Planetary Governor may harbour territorial ambitions of his own, but whatever their motivations, the result is the same -- ruthless and immediate repression. These revolts must be dealt with swiftly and graphic examples made of the ringleaders, for if just one planet is shown to succeed in such a quest, others will certainly follow. It may take centuries to quash a revolt, but no Human world is ever allowed allowed to secede for long from the Imperium. Assassination, planetary assault and, occasionally, Exterminatus are all righteous tools that may be employed to bring the wayward world to heel.
  • Popular Revolt: It is a regrettable fact that many citizens of the Imperium suffer from the most horrendous living conditions in less-than-ideal environments. From time to time, a particularly bold demagogue may rally his fellows and overthrow a planetary government. This only becomes a problem if they then go on to defy the authority of the Imperium, otherwise the new regime will go unmolested -- it is ordinarily not the Adeptas' way to impose a specific governmental form upon a population. Foolishly, flush with success, the rebellious people of a world often go on to do just that, mistakenly identifying the Imperium with their oppression and not their salvation. Also, it is sometimes better on planets with a particular strategic importance to ensure continuance of a specific form of governance. In both these cases the military forces of the Imperium are brought to bear.
  • Xenos Infiltration: There are many creatures in the universe that exist by using other creatures as their proxy. These may be creatures from the physical realm, such as Genestealers, or beings such as the Enslavers, who somehow have a material being but dwell within the Empyrean. Sometimes these worlds carry on seemingly as normal, the rest of the galaxy unaware of the dark, alien cancer eating at their heart. As often as not, the alien-dominated population will rise up in armed rebellion. In either case, utter destruction of the infested inhabitants is, regrettably, the best course of action. This can be effected via Exterminatus, through tectonic destabilisation, the use of Cyclonic Torpedoes or viral (general or geno-tailored) bombardment, dependant upon the importance of the world and the possibilities for subsequent recolonisation.
  • Daemonic Infiltration: A planet may turn to worship of the Dark Gods under a number of circumstances. Suppression of such revolts must be handled carefully -- destruction of the population may be the Ruinous Powers' actual aim, as the psychic feedback in the Immaterium caused by the sudden deaths of millions of people can be enough to permanently open a rift between the Warp and realspace. Planetary invasion by specialist formations like the Space Marines or the Grey Knights is advisable, followed immediately by planetary cleansing or destruction through Exterminatus.

Imperial Secrecy

"These daemons, they hate us with a malevolence and intensity beyond words. It is their nature, their purpose to worm their way through the skin of reality and unleash horror upon our realm. Yet just as they are but puppets of their dark masters, so they can also act as puppeteers. They take the minds and souls of potent psykers, brave warriors, cunning generals and devoted healers and they...twist...all that might benefit Humanity. Their poison spreads until the Imperium's greatest champions become instead its most terrible foes. Chaos peers into the collective Human soul and uses what it finds to turn us against ourselves. That, acolyte, is why it is the greatest danger we face."

—Inquisitor Lhorcus Phrecht

To protect its citizens from the insidious temptations of Chaos, the Imperium of Man long did its best to hide the existence of the Chaos Gods, Daemons and the Chaos Space Marines from public knowledge. Only certain Space Marines, Sanctioned Psykers and the members of the Inquisition were permitted to know the Imperium's darkest secret.

It was long Inquisitorial policy to mind-wipe even members of the Adeptus Astartes, including entire Chapters in some cases, after exposure to the daemonic.

All others are either put to death after exposure to the reality of Chaos to protect the Imperium from their possible corruption, or if they have been a valuable servant to the Imperium, they are allowed to live but required to undergo memory modification or even, in extreme cases, a mind-wipe.

This is a policy that has been in place since before the Emperor of Mankind was interred within the Golden Throne, when only He and His primarchs knew that the Warp contained intelligent entities capable of possessing individuals in realspace.

But even the Emperor did not reveal to His primarchs during the Great Crusade the full truth that the Warp was not just a seething cauldron of psychic energies inhabited by entities similar to xenos, but was actually populated by malign intelligences akin to the supernatural beings of ancient Human myth and superstition.

He chose not to explain that the Empyrean was dominated by the Ruinous Powers and their daemonic servants, for fear that this knowledge alone would lead too many of the primarchs to take actions that would lead to their corruption.

To fight a Daemon army is to fight a twisting tornado of unreason and despair that forever changes those who must confront its horror. As such, the Imperium believes that it cannot allow the knowledge that such foes actually exist to spread, since even the simple knowledge of Chaos' existence may mark the start of an individual's fall to damnation.

The Human survivors of conflicts with the daemonic were invariably confronted by the agents of the Inquisition and mind-wiped, quarantined for life in forced labour camps or even -- in extreme cases -- made the subjects of a worldwide Exterminatus event.

Over the aeons, the galaxy has witnessed Warp-based catastrophes and daemonic incursions beyond counting. Since the inception of the Inquisition after the Horus Heresy, even the fact that such a thing is possible is deemed too dangerous for the citizens of the Imperium to know, for such knowledge breeds heresy as surely as a flyblown corpse breeds maggots.

Because of this, the vast majority of knowledge concerning daemonic incursions has been eradicated from extant Imperial public records. What is known is recorded only in proscribed Imperial texts and heretical xenos scripts that the Inquisition has yet to destroy.

However, in the wake of the opening of the Great Rift at the start of the Era Indomitus, this policy of secrecy has been somewhat relaxed, at least for the Adeptus Astartes, due to necessity. Before the opening of the Great Rift, the vast majority of Astartes were expected to be as ignorant about the existence of Daemons as any other citizen of the Imperium.

In truth, it was hard to find an Astartes who had not fought Daemons by the end of the 41st Millennium. Yet the Inquisition in the Time of Ending was well-known to mind-wipe entire Chapters after certain incidents, though not every Chapter was willing to submit. Some like the Space Wolves resisted any intrusion on their traditional autonomy forcefully.

But in the Era Indomitus, with the galaxy now riven in half by the birth of the Cicatrix Maledictum, daemonic incursions are so common, and Space Marine responses so necessary, that suppressing the knowledge of the existence of Daemons among the Astartes has simply become pointless.

Other Science Fiction Influences on the Imperium of Man

The Imperium itself, in keeping with the dystopian themes of Warhammer 40,000, is a highly oppressive techno-theocracy obviously influenced by the Padishah Empire found in Frank Herbert's Dune.

It also closely resembles Isaac Asimov's Galactic Empire in the Foundation series, with millions of star systems only loosely connected with the governing center, where technology is becoming a myth rather than a science, with extreme persecution of those questioning the morality or validity of the endless conflicts and divine rule of the Emperor.


  • Avenging Son (Novel) by Guy Haley
  • Black Crusade: Core Rulebook (RPG), pp. 20-27, 29
  • Codex: Imperial Guard (6th Edition), pg. 6
  • Codex Imperialis (2nd Edition), pp. 10-15
  • Codex: Militarum Tempestus (6th Edition), pp. 5-13
  • Codex: Space Marines (6th Edition), pp. 6-7
  • Codex: Space Marines (5th Edition), pp. 6-7
  • Dark Heresy Core Rulebook (RPG), pp. 246-264
  • Dark Imperium (Novel) by Guy Haley, Ch. 9 "Imperator Gloriana," pp. 96-97
  • Deathwatch: Core Rulebook (RPG), pp. 284-300
  • Gathering Storm - Part Three - Rise of the Primarch (7th Edition), pp. 4-93
  • The Horus Heresy - Book One: Betrayal (Imperial Armour), pp. 10-11, 15-18, 21-25
  • Rogue Trader: Core Rulebook (RPG), pp. 302-315
  • Space Marine (2nd Edition), pg. 5
  • Space Marine (1st Edition), pp. 3-7
  • Warhammer 40,000: Rogue Trader (1st Edition), pp. 132-135, 138-142, 144-148, 150-151 , 153-157
  • Warhammer 40,000: Core Book (9th Edition), pp. 20-23, 42-43, 45-46, 60 (Quote)
  • Warhammer 40,000: Rulebook (8th Edition), pp. 22-39
  • Warhammer 40,000: Rulebook (6th Edition), pp. 134-154, 158-177, 180-183, 189-191, 195, 402-403, 408-409
  • Warhammer 40,000: Rulebook (5th Edition), pp. 101-125
  • Warhammer 40,000: Rulebook (4th Edition), pp. 88, 90-91, 92-97, 100-101
  • Warhammer 40,000: Rulebook (3rd Edition), pp. 98-115