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Imperium of Man

Capital: Terra

Major Species: Human, Abhumans

Goverment: Theocratic oligarchy

Head of State: Emperor of Mankind

Head of Government: Roboute Guilliman

Governing Body: High Lords of Terra,

State Religous Body: Maintained by Ecclesiarchy


  • Astra Militarum (Imperial Guard)

  • Imperial Navy

  • Adeptus Astartes (Space Marine)

  • Collegia Titanica

  • Sisters of Battle

  • Legiones Skitarii

  • Cult Mechanicus Battle Congregations

  • Planetary Defense Force


  • Adeptus Arbites

  • Inquistion

  • Adeptus Custodes

  • Sisters of Silence

The Imperium of Man is the galactic empire under which the majority of humanity is united. The founder and nominal ruler of the Imperium is the god-like Emperor of Mankind, the most powerful human psyker ever known.

The Imperium is the largest and most influential political entity in the galaxy, consisting of at least a million worlds which are dispersed across most of the galaxy. An Imperial planet might be separated from its closest neighbour by hundreds or 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 in its control.

Several aliens and forces - the forces of Chaos, Tyranids, Eldar, Dark Eldar, Orks, Tau, Necrons - challenge the supremacy of the Imperium. From within, the Imperium is threatened more insidiously by rebellion, mutation, rogue psykers, and subversive cults. Without the protection of the Imperium, mankind would fall prey to the countless perils that threaten it.

History of the Imperium

The Imperium was founded by the Emperor, also called The Immortal Emperor, God-Emperor, and the Master of Mankind, at the end of the Age of Strife - a very long period of anarchy, war, and destructive regression which brought humanity to the brink of destruction and reversed the technological progression made during the Dark Age of Technology. In the Unification Wars, the Emperor led his proto-Astartes known as Thunder Warriors to victory in unifying Terra for the first time in millennia.

As the Warp storms of the Age of Strife subsided, after having secured the scientific posts and spacedocks of Luna, along with the factories and scientists on Mars, the Emperor began to unite mankind under his rule. A vast navy was built, with which his armies undertook the Great Crusade, which lasted for about two centuries. During this two hundred year-long military campaign, the Emperor employed his most potent military units, the Space Marine Legions, led by their leaders, the Primarchs. These, combined with the might of the Imperial Army (which was later separated into the Imperial Guard and the Imperial Navy), Custodian Guard, Sisters of Silence, and Martian Mechanicum forces that included the Collegia Titanica and Legio Cybernetica saw thousands of human worlds brought together under the Imperium. The Great Crusade ended with the corruption and treachery of the Primarch Horus, the instigator of the Horus Heresy.

The rebellion was fought across the galaxy. Horus, seeking to achieve a swift and decisive victory, led most of the traitor forces in a direct strike at the capital of humanity, in the Battle of Terra. In the final decisive battle between the Emperor and the Arch-Traitor, Horus was slain, leading to the breakup of the rebellion and the exile of the traitors to the Eye of Terror. However, the Master of Mankind was himself mortally wounded. According to his instructions, he was placed on the life-preserving Golden Throne, where, for nearly ten thousand years, he has remained. Though physically a carcass incapable of movement or communication, his omnipotent will extends across the million worlds of the Imperium, beaming the psychic energy of the Astronomican, soul-binding psychic humans and struggling against the daemons of the Warp. He endures by his undying will, and by the sustenance that only the souls of sacrificial psykers can provide. By the numberless masses of humanity, he is worshipped as a god.

The immediate period following the Heresy, The Scouring and Age of Rebirth, saw the Imperium slowly rebuild its might and control over the domain of man. It also saw the last of the Emperor's loyal Primarchs either fall in battle, become gravely wounded, or disappear altogether. Nonetheless, in the subsequent age known as The Forging, the Imperium enjoyed a period of growth and expansion. The Imperium's period of relative peace ended abruptly in mid-M32 when an Ork Warboss known only as The Beast launched the greatest Waaagh! ever encountered. The Beast was only halted at great cost by the Adeptus Astartes.

The Imperium saw further periods of severe instability throughout M35 and M36, experiencing civil wars during the Nova Terra Interregnum and Age of Apostasy. This period saw the worst internal violence since the Heresy. Following the Age of Apostasy, the Imperium was again heavily reorganised and many heretics purged in the Age of Redemption. This new fervour culminated in a series of major Crusades and Wars of Faith most notably the Redemption Crusades and Macharian Crusade. However, while successful, this period exhausted the Imperium's military forces, and in The Waning, many worlds were lost to Xenos and Chaos attacks as well as internal rebellion.

The effects of The Waning ultimately culminated in late M41, known as the Time of Ending. Here the exhausted Imperium not only faced rejuvenated old threats, but also terrifying new enemies like the Tyranids and Necrons as well new smaller but dynamic alien empires such as the Tau, Noisome Reek, and Ulumeathic League. Beset on all sides by Heresy and alien invasion, the future of the Imperium seems bleak. The Black Crusade saw both the destruction of Cadia and the formation of the Great Rift, which has effectively split the Imperium in two. However, some hope has been renewed thanks to the rebirth of the Primarch Roboute Guilliman, who has launched the Indomitus Crusade to reclaim worlds lost within the Dark Imperium.

Political Structure of the Imperium

The Imperium is still nominally ruled by the Emperor of Mankind. However, since his ascension to the Golden Throne, the duty of actually ruling the Imperium falls to the Senatorum Imperialis - the Imperial Senate, formed by the twelve High Lords of Terra. The identities and responsibilities of these High Lords may vary, as individuals inevitably die and their influence grows and wanes. Still, its members are always the leaders and representatives of the most powerful Imperial organisations.

This system endured for ten thousand years until the end of the 41st Millennium when the revived Primarch Roboute Guilliman became Lord Commander of the Imperium and ruled over even the High Lords.

The Imperial government is divided into four main bodies: the Adeptus Terra (The Priesthood of Terra), the Adeptus Mechanicus (the Priesthood of Mars), the Adeptus Ministorum (State Church), and Inquisition (Secret Police). These in turn answer to the Senatorum Imperialis, who rule in the name of the Emperor.[3e] In practice, most of the organisations comprising the Imperium are divisions of the vast Adeptus Terra. There are countless divisions, and some are so secretive their existence is known only to a few. The most well-known of the "secret" organisations is the Officio Assassinorum. Other organisations are secret enough that nothing besides their mere existence is known, such as the Officio Sabatorum and the Templars Psykologis.

The most important and well-known Imperial organisations include:

  • The Adeptus Terra, which includes:

    • The Administratum - Responsible for administrative functions, it is the largest division, numbering countless scribes and petty officials. It administers the Imperium at every level, assessing tithes and taxes, conducting population censuses, recording and planning. It consists of innumerable subdivisions, offices and departments.

      • The Departmento Munitorum - A department of the Administratum, responsible for administering and supplying the Imperial Guard.

        • The Ordo Tempestus - Elite military force

  • The Officio Assassinorum - The most subvert of all the known Imperial divisions, the assassins are responsible for removing key leaders of an enemy.

  • The Estate Imperium

  • The Imperial Fleet

    • The Navis Nobilite - The self-ruling body of Navigators who pilot Imperial vessels through the Warp.

  • Governors of individual Imperial worlds

  • The Adeptus Astra Telepathica - The Imperium's network of astropaths, responsible for transmitting faster-than-light messages through the Imperium.

    • The League of Black Ships - Psyker-gatherers

    • The Scholastia Psykana - Trains Sanctioned Psykers

  • The Adeptus Astronomica - Responsible for maintaining the Astronomican, which is used by the Navigators to navigate through the Warp.

  • The Adeptus Astartes - Also known as the Space Marines. They are the infamous bio-enhanced shock troops of the Imperium.

  • The Adeptus Custodes - Guardians of the Emperor's physical form.

  • The Adeptus Arbites - Galactic police force which enforces the "Lex Imperialis" - the Imperial law.

  • The Logos Historica Verita - Historical & archival reformation agency

  • The Inquisition - A secret police and internal affairs organisation, they are responsible for investigating any potential threat to mankind or the Imperium. Its agents hunt down heretics, traitors, alien infiltrators and even daemons. They necessarily exist beyond the Adeptus Terra's authority, as part of the Inquisition's role involves rooting out corruption and gross incompetence from the Imperium itself. They answer only to the Emperor and to themselves.

    • Ordo Hereticus - Confronts the Threat Within

    • Ordo Xenos - Confronts the Threat Without

    • Ordo Malleus - Confronts the Threat Beyond

    • Ordo Minoris

  • The Adeptus Mechanicus - Technicians and scientists who build and maintain Imperial equipment, vessels, and weapons of war, headquartered on Mars.

    • Priesthood

    • Explorator Fleets - Explore new parts of the Galaxy

    • Prefecture Magisterium - Secret Police of the Mechanicum

    • Forge Worlds - Produce vast amounts of technology for the greater Imperium

  • The Adeptus Ministorum - also known as the Ecclesiarchy, the Imperial church which maintains the Imperial creed and faith.

    • Holy Synod - Ruling body of the Ecclesiarchy

    • Creed Temporal - Deals with secular business

    • Adepta Sororitas - All-women organisation that includes the Sisters of Battle

    • Missionarius Galaxia - Fields Missionaries to spread and maintain the Imperial Cult on worlds.

    • Schola Progenium - Orphanage & civil servant training institute

    • Shrine Worlds

Imperial Military

As the largest single known polity in the Galaxy, the Imperium maintains a wide array of military forces. At any given times there are countless billions fighting for the Imperium of Man. Similar to its political organisation each branch of the Imperium's military is independent, with their own duties, rituals, chain of command, tactical acumen and gear of war. Though diverse, the forces of the Imperium often work in conjunction with each other, and the larger the battle, the more likely it will be to see multiple Imperial factions engaged in the same war. Massive conflagrations, such as the Chaos invasions known as the Black Crusades or a major war zone such as the one surrounding the planet Armageddon, will attract representatives from all of Mankind's military institutions.

The military forces of the Imperium consist of:

  • Planetary Defense Forces - Often abbreviated to PDFs. These are independent armies raised and commanded by the Governors of individual Imperial worlds. Though poorly trained and equipped compared to the rest of the Imperium's forces, they serve as the first line of defence.

  • The Imperial Guard - The largest single military arm of the Imperium, consisting of vast armies of unaugmented human Guardsmen. It falls under the control of the Administratum's Departmento Munitorum.

    • The Ordo Tempestus - Elite forces of the Departmento Munitorum

  • The Imperial Navy - The military branch of the Imperial Fleet. Consists of large warfleets of spacecraft tasked with not only space combat but also transporting the Imperial Guard

    • The Aeronautica Imperialis - Atmospheric warfare branch of the Imperial Navy

  • The Space Marines - Elite genetically modified warriors divided into independent armies known as Chapters.

  • The Sisters of Battle - The all-female military arm of the Imperial church, the Ecclesiarchy.

  • The military forces of the Adeptus Mechanicus, which include:

    • The Collegia Titanica - Operates Legions of titanic war machines known as Titans

    • The Legiones Skitarii - Cybernetic soldiers that act as the standing armies of Forge Worlds.

    • Other miscellaneous smaller and specialised armed wings including Knight Houses, the Electro-Priesthood, Legio Cybernetica, Ordo Reductor, Auxilia Myrmidon, Centurio Ordinatus, and Fleet. These are often deployed together in formations known as Battle Congregations.

  • The Sisters of Silence - Psyker-hunters of the Adeptus Astra Telepathica and guards of the Black Ships.

  • The Adeptus Custodes - The elite guardians of the Emperor. For most of the Imperium's history, they have remained at the Imperial Palace but recently have ventured forth on Crusades.

  • The forces of the Inquisition - Besides the Inquisitors and their retinues, the Inquisition's forces include:

    • The Grey Knights - Chamber Militant of the Ordo Malleus

    • The Deathwatch - Chamber Militant of the Ordo Xenos

    • The Sisters of Battle - Chamber Militant of the Ordo Hereticus

    • Inquisitorial Stormtroopers - Standard soldiers who act as the guards and enforcers of the Inquisition.

    • Independent fleet assets which include Inquisitorial Black Ships and Inquisitorial Cruisers.

  • The Arbitrators - The armed wing of the Adeptus Arbites, the Imperium's police force. Heavy armed and equipped, they often see combat during issues of planetary invasion and rebellions

  • The Officio Assassinorum - Agency which deploys specialised deadly assassins.

  • Frateris Militia - ad hoc militias raised by the Ecclesiarchy during Wars of Faith.

Imperial Domain

The disparate and widespread nature of Imperial territory means that a strongly centralised government would be unfeasible. The Imperium divides the galaxy into five administrative zones called Segmentae Majoris:

  • Segmentum Solar - inner core and heart of the Imperium.

  • Segmentum Pacificus

  • Segmentum Obscurus - a heavily-fortified region due to the dangers posed by its most infamous element, the Eye of Terror.

  • Segmentum Tempestus

  • Ultima Segmentum - the largest province of all; its furthest extents are beyond the range of the Astronomican.

The Segmentae are the Imperium's primary administrative division. Each is divided into sectors, which are areas of space. The sectors, in turn, consist of subsectors, each containing a number of star systems which in turn are made up of individual worlds. These divisions and subdivisions are levels forming an administrative hierarchy. Each Segmentum Commander oversees his Sector Commanders, who in turn oversee Subsector Commanders, who oversee the individual Planetary Governors. The higher ranks in this system are usually combined with a basic planetary governorship as well as interplanetary duties. This system is the means by which the Imperium maintains control of the separate planets that comprise it.

The borders of the Imperium are marked by several uncharted regions of space which lay beyond the range of the Astronomican, areas which are frequently viewed with uncertainty and fear by Imperial citizens.[5] These include the Halo Zone on the Imperium's western-most border, the Halo Stars to its northwest, the Ghoul Stars to its northeast, the Veiled Region and Mandragoran Stars to its south, and the Eastern Fringes to its eastern-most border.

Following the Thirteenth Black Crusade and the resurrection of Roboute Guilliman, much of the Imperium's northwestern frontier became cut off from Terra. Becoming known as Imperium Nihilus, Guilliman has launched a new Crusade to reclaim these worlds.

Planetary Classification

Due to its vast magnitude, the Imperium can afford for entire worlds to become specialised places where a majority, perhaps even the entirety, of the population is devoted to a single task. This could be heavy industry, military training, manufacturing, mining or agriculture. Planet-wide dedication serves to simplify logistics and increase outputs. While not all Imperial worlds can be classified, the most commonly encountered types are:

  • Hive World

  • Forge World

  • Agri World

  • Cardinal World

  • Cemetery World

  • Civilised World

  • Death World

  • Feral World

  • Feudal World

  • Fortress World

  • Industrial World

  • Knight World

  • Mining World

  • Paradise World<