There are actually two possibilities that I can see for his death: Either Gennosuke simply beats him with his 1337 power (and finishes him somehow), or he gets badly wounded, and right when he's about to heal himself, Oboro looks at him, stopping his healing power, and he will die a miserable death like a normal man (and is finished after that.)

I'm not anymore as sure as I was before that this series will end with everybody dead. It could still happen, but now I'm thinking the chances are 50-50, or something.