God-Emperor

Once a living man, his body can no longer sustain his life so his body remains in tact by force of technology and sheer will and the sacrifice of hundreds of thousands of psykers a year. His broken body has sat on his throne of Holy Terra for 10,000 years and from it casts a beacon that can be seen through the Immaterium of the Warp which keeps the Imperium together.

From his own gene-seed he created the 20 primarchs which in turn created the 1,000 or so legions of the Astartes, or Space Marines.

God-Emperor

Here Be Dragons Blabble Rodell