6. X-Cutioner
Marvel ComicsAlthough something of a minor character who has very rarely appeared in the comics, the X-Cutioner is actually a very interesting and dangerous character. The X-Cutioner is not actually an outright "villain", as such, but he would certainly fit the criteria of "antagonist" and he would make for a very interesting character in the X-Men movies. He is Carl Denti - an entirely human former FBI agent who is utterly obsessed with stalking and killing mutants who have killed humans. He has managed to acquire an array of both alien technology (including Shi'ar power armor and Z'nox sensors) and advanced Earth technology (including Sentinel propulsion units) to make himself formidable enough to do so in a truly and genuinely threatening manner. Although the mutants of the X-Men movie franchise have seen human opposition in the form of the likes of Bolivar Trask and Senator Kelly, they haven't seen any who are a physical threat in their own right go up against them. The X-Cutioner would, therefore, be an unusual and refreshing change.