Oh, and for the record -- heroes shouldn't kill. It's not a Seduction of the Innocence thing, it's a moral high-ground issue. As beings of greater than average power they should be able to comprehend that the decision to take a life is not theirs. Nobody (except possibly a creator(s)) has the right to determine whether a human life can be ended. Simple as that. The highest moral ground any society can take is to keep those who feel they can end human life away from humans. They do not have the authority to end life themselves. That's what makes a hero interesting.