If someone needs to kill him, I can totally volunteer Kaine. He used to be an assassin, so he's no stranger to actually killing people regardless of whether or not they deserved it (he just has this thing called a conscience now and it sucks).

Also, he's got a costume that can go invisible (well, he had one, he just has to get it back after giving it up temporarily) so he can do anything that needs to be stealthy.