From Warhammer 40k - Lexicanum
The Imperium of Man is the galactic empire under which the majority of humanity is united. The founder and ruler of the Imperium is the god-like Emperor, the most powerful human psychic to date. Founding the Imperium ten thousand years ago, he continues, at least nominally, to lead it.
Other Imperial Organisations
- Inquisition - 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, 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.
- Adeptus Ministorum - The Imperial church which maintains the Imperial creed and faith.
Imperial Military Forces
The military forces of the Imperium include:
Articles of Note
The Adeptus Terra, also known as the Priesthood of Earth, is the central organisation of the Imperium, to which most of the Imperium's other official departments and organisations belong. Only the Ecclesiarchy and the Inquisition are not formally a part of the Adeptus Terra.
Departments of the Adeptus Terra
The most important and well-known Imperial organisations include:
- The Administratum - Responsible for administrative functions, it is the largest division, numbering countless scribes and petty officials. It administrates the Imperium at every level, assessing tithes and taxes, conducting population censuses, recording and planning. It consists of innumerable subdivisions, offices and and departments.
- Departmento Munitorum - A department of the Administration, responsible for administering and supplying the Imperial Guard.
- Adeptus Astra Telepathica - The Imperium's network of astropaths, responsible for transmitting faster-than-light messages through the Imperium.
- Adeptus Astronomica - Responsible for maintaining the Astronomican, which is used by the Navigators to navigate through the Warp.
- Navis Nobilite - Navigators who pilot Imperial vessels through the Warp.
- Adeptus Mechanicus - Technicians and scientists who build and maintain Imperial equipment, vessels, and weapons of war.
- Adeptus Custodes - Guardians of the Emperor's physical form.
- Adeptus Arbites - Galactic police force which enforces the "Lex Imperia" - the Imperial law.
- Officio Assassinorum - The most subvert of all the known Imperial divisions, the assassins are responsible for removing key leaders of an enemy.
- Imperial Fleet - Responsible for all interstellar travel.