Billions of years ago, a mad warlord had a problem. He had an overpopulation problem, caused by the people in his sector having too many kids. So this warlord had an idea, to translate all the people to earth, where he would feed them to a gigantic, horrific monster.
Unfortunately for the warlord, some of the many beings that he had chosen to feed the monster either escaped or were eaten and later reincarnated. So the overlord told the monster to pretend to be God, and to indoctrinate the people with various lies and religions so that they will allow their life force to be tapped by the monster-God.
So what does this sound like...an overly complicated video game or a cult?
For this write up to make sense, the nodes on Xenogears and Xenu should both be read.