I'm really curious about the specifics of what he's doing that's so horrible, but really, that's besides the point. The point isn't how the player is being problematic, the point is
that a player is being problematic. Details are interesting to know, but fundamentally unimportant. Once you've made up your mind that he's screwing up your game -- and you clearly have -- all that matters is that he's fucking up what's supposed to be a relaxing, pleasant, social experience. By that point it doesn't matter what happened, or how, or who started it, or why, or anything else. What matters is that one of you needs to stop showing up to the game, because otherwise BOTH of you will end up not having fun.
If it's your game and you're hosting, the decision's already made about which of you that will be. It's your game. He's gone.
Kill the character. He does it again, kill it again. At some point he leaves or gets the picture. Everyone else enjoys the constant splat.
That's a pretty passive-aggressive way to handle the problem, and meanwhile (a) the game is being derailed, and (b) you've got to figure out why the rest of the group isn't getting murdered, too. It's goofy.
You cannot handle an out-of-game problem in-game.
You cannot handle an out-of-game problem in-game. Not only doesn't it work, but it's retaliating against immaturity with immaturity. Don't throw handfuls of dice and GM fiat at him until he goes away, that's just returning bullying with bullying.
Sit down and talk to the player like you're both grown-ups. It's not that hard. Tell him you don't like what he's doing, tell him his playstyle isn't fitting the feel you're going for, and ask him not to show up next week. It's not the end of the world. Just do it. In the grand scheme of things, it's not that big a deal, so the best advice is to just handle it. There's no need for hyperbole or melodrama, accusations of usurpation or corruption, and there's not REALLY any need for genuinely hurt feelings. It's just a game. The entire point of games is to have fun, and if that's not happening, you're doing BOTH of you a favor by not gaming with him any more.
Just bite the bullet and tell him you don't want him in the game any more. Done.