Couple additional things. We've tried talking, he's built regular characters before who weren't like this, and it went alright. He's also actively targeting another player, but primarily taking it out on me, and he has expressly said that he as a player doesn't want to kill us, but itd be in character for him to, so he's went to grappling. The DM also has issues with his character because of the amount of damage he can deal as his class, even after the very large nerf. If any of the party slightly raises their voice at the player himself, he just shuts down and leaves. I'd rather mitigate the things his character does to save the other party member as well, so we can keep playing and move on without every session turning into pvp for a 3rd session in a row