10 X-Men Fates Worse Than Death

10. Becoming Onslaught

Bishop is a mutant who lives in a dystopian future where his kind live in slums and concentration camps. His ally, Witness, informed him that society collapsed in 1996 after the X-Men were killed by a traitor on the team. Bishop decides to go back in time to stop this traitor before they have a chance to exterminate the protectors of mutantkind.

After Bishop travels to the present timeline, he is baffled to learn that the traitor... is Professor Charles Xavier. But how could this be?

Well, the X-Men's mentor was so terrified he could lose control of his powers, he sealed away all his negative emotions many years ago. After several decades, these dark thoughts magnified exponentially, transforming the professor into a dark entity called Onslaught. The X-Men managed to separate Xavier from Onslaught but the malevolent creature had grown so powerful by that point, it was self-sustaining.

Although it was ultimately defeated by the superheroes of Earth, it was only after hundreds of civilians were killed. Xavier was horrified to learn he had nearly destroyed the same world he had vowed to protect from the forces of evil.