Deadpool

Because…why not? Deadpool is no hero – and he doesn’t really need too much of a reason to completely obliterate the X-Men. Of course, he’d be an ally at first – maybe he should even appear in several cameos.

But, in the end, his true colors need to be revealed. And what could the ultimate scope be for Deadpool? Just as when he killed the Marvel universe, maybe he’ll get tired of being just a comic book character turned comic book movie superhero. So maybe a change of pace would be all he needs.

We know – he doesn’t really possess the power to solo alone against the entire X-Men mansion. But his ability to regenerate from any wound, along with his immortality, could mean that he’ll be able to come back again and again, until the job is done.

And he can always bring some allies…

And, afterwards, we could have another franchise reboot!