The God-Emperor of Mankind is the immortal ruler of the human species, the Master of Mankind who has guided humanity from the shadows for tens of thousands of years. Born on ancient Terra, he emerged in the closing days of the Age of Strife to unite the scattered, warring tribes of humanity and lead the Great Crusade to reclaim the stars. To his loyal servants he is a deity worthy of absolute worship; in his own time, he named himself no god at all, but a rationalist and a guide.
Betrayed in the Horus Heresy by his favoured son, the Emperor was broken almost unto death, and for ten thousand years his shattered body has been sustained upon the Golden Throne. From that arcane machine his soul blazes forth as the Astronomican, the psychic beacon by which the ships of the Imperium navigate the treacherous warp. Each day, thousands of psykers are sacrificed to sustain him — a living corpse, a god who cannot die.
He is defended by the golden Adeptus Custodes, his personal guardians crafted for that singular purpose, and worshipped by the zealous Adepta Sororitas, whose faith burns bright enough to work miracles. Whether he remains a conscious will guiding humanity's fate or merely a decaying relic venerated by a desperate species, none can say — yet his light still holds back the darkness, and by his name the Imperium endures.