Except that's only for the light novel. Manga's already started setting up another big bad in store, due to King Jioral mentioning "a certain hero which gave him the ability to rule over both the living and the dead".
1. I mean, he chills and gets to fuck for the rest of his life while basically being the Adam of the world, repopulating everything singlehandedly.
2. Has it been dropped? They made it pretty clear that his body is basically destroyed. If he dies again, than he won't be able to return. We'll...