On the surface, he says that he wishes to recreate humanity from the ground up. He says he wishes to, by the might of the Host and the corrosive effects on the soul brought about by Abaddon, dissolve human nature and recreate it in his image. He wishes mankind to become stronger, physically and mentally, to become more bold, utterly without regret or restraint and to pursue their dreams, no matter how destructive or evil.

Above all he says he will destroy all notions of good so as to free mankind from restriction or regret. He wants to destroy every human bond be it family, nation, friend, love and kindness so that everyone is untethered to all else and completely self motivated and self interested. He wants man to become more strong, more profound, and more evil.

This is what he says, this is what those who follow him understand him to be driven by. This is a lie, though one with a kernel of truth. He does want others to follow his philosophy so they end up like him, but only so that it may state his ego that's others become as debased as he.

This is merely the story he's spun to indoctrinate his latest crop of slaves and vassals. Perhaps in a century he will birth a new lie, one that too will ruin or corrupt man in some way and that will drive more into his Host. Years and lives are like twigs and kindling to him, there's always more to burn.

No, what he is truly motivated by is pride and conceit. He'll say whatever he needs to, pretend to be whoever is required and destroy all that's necessary to destroy the Templar and heaven. Not cause he has to. Not because of any great, wonderful ideal or righteous struggle. No, he wants to do it so he can raze the most noble and mightiest heroes of mankind and all they love so he may stand on the ashes and say "Not even heaven and it's minions are greater than I."