The principal faction of Warhammer 40,000, the Imperium of Man was founded by the The God-Emperor of Mankind and serves as the government for humanity. It has fallen far from the ideals of scientific enlightenment it was founded upon, instead consumed by intolerance, ignorance, and religious fanatacism following the events of the Horus Heresy and other crises. Its icons are a double-headed eagle known as the Aquilla and the skull.
Its armed forces consist of the famous Adeptus Astartes, the Space Marines, and countless, ordinary Imperial Guardsmen, as well as an extensive navy. Internal security is handled by the Inquisition and its associated forces, such as the Officio Assassinorum and the Adepta Sororitas, the Sisters of Battle. In charge of its industry is the Mechanicum based on Mars, infamous for their religious reverence of what technology the Imperium has been able to preserve.
Its most famous motto is "The Emperor Protects."