If Exxy jumped out of the screen with a mission to kill the world... Well, for one he's extremely emotional and been through so much that he'd probably beg to be killed in the end. But for me, it'd be hard but I'd do it for both him and the world. I always can't help but feel bad for the guy, but it was always the best thing to roleplay him.
Honestly, I wouldn't know if I could, and it'd probably be hard but I would do it. In being such a powerful shapeshifter he'd probably be able to succeed, and maybe even be able to kill me, but if I was able to... yeah. I think I've told ya my answer already.