nathan summers
Stryfe handled both Cable and X-Man in the story-arch " Blood Brothers " which debuted all three of the Summers-spawn together. Apparently Stryfe had the ability to usurp Nate and Nathan with relative ease. Without Cable there to aid him would X-Man stand a remote chance of defeating the Chaos-Bringer? Remember; Stryfe is essentially Cable without the techno-organic virus, he's a super genius not to mention the fact he has some measure of control over his own unfettered abilities as well as supreme hand to hand skills. Discuss.