In canon Ye Zun is a supervillian who basically wants to eat the entire world and remake it to his ideal world, in this AU he would start small and work his way up. It does help that the more lives he absorbs, the stronger he gets so he may be a good source of reluctant buddies :3

So long as his brother is saved for him, he doesn't care what happens to the rest. Unless it's one of his minions those he is slightly possessive of as well.