The era of the devas

This story takes place after the armageddon, the divine beings that is to say the gods and the demons have almost died out leaving the universe without a guardian against the invasions of other dimensions.
The last seeing deities that merged all the worlds into a hyper world capable in the hope of seeing new deities born.
So to do this the deities sacrificed 80% of the population of each species and their own being to create a system capable of testing and helping these mortals on the path to godhood.
The system thus created to give each people a way to become a god and to create a barrier to keep the universe from the eyes of invaders.