The 7 Biggest Traitors in X-Men Comics

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Over the years, the X-Men comics have been known for their complex, long-running storylines. Writer Chris Claremont, who significantly boosted the team’s popularity, was famous for planting seeds for plots that wouldn’t come to fruition for years. In the 1990s, other writers attempted similar long-term planning with the ‘X-traitor’ storyline, but the reveal didn’t satisfy most fans. However, it did pave the way for more stories featuring traitors within the X-Men universe – a trope that, while not always frequent in comics generally, has become a recurring theme in X-Men, particularly in the more dramatic stories of the 21st century.

Over the years, the X-Men comics have featured many characters who’ve betrayed their team. These individuals, whether heroes or villains, have caused significant harm to their fellow mutants. Here are seven of the biggest traitors in X-Men history – characters for whom loyalty is a flexible concept.

7) Sabretooth

Sabretooth is Wolverine’s biggest enemy and is infamous for his treachery. Throughout their history, despite occasionally teaming up, Sabretooth consistently betrays Wolverine. It’s a simple rule: you can’t trust Victor Creed. The X-Men have repeatedly learned this the hard way, as their attempts to rehabilitate him always end with him exploiting their trust and turning against them. Trusting Sabretooth is like trusting a wild animal – the moment you relax your guard, you become a target.

6) Bishop

Bishop traveled from the future, bringing with him information about a dangerous traitor. He quickly became a powerful member of the X-Men, determined to prevent the grim future he knew. However, when Hope Summers was born, he shockingly turned against the team, believing she was the cause of the disastrous future he’d come from and attempting to kill her. This sparked a chase through time, with Cable protecting Hope and Bishop pursuing them. Ultimately, Cable left Bishop stranded far in the future, where Bishop realized he’d been wrong about Hope. Upon returning to the present, he was forgiven by his teammates.

5) Gambit

Gambit quickly became a fan-favorite X-Man, but his past was always shrouded in mystery. He was even suspected of being a traitor within the X-Men at one point. It was revealed he’d worked for Mister Sinister, guiding the Marauders to the Morlocks during the “Mutant Massacre,” but was horrified by their actions and ultimately left, even saving Marrow as a child. Later, he shocked everyone by betraying the X-Men and serving Apocalypse as the Horseman of Death, eventually returning to work for Sinister, helping him and the Marauders attack the X-Mansion. He even clashed with Bishop, as Sinister wanted to ensure Hope’s survival. Despite all this, Gambit ultimately turned on Sinister, returning to the path of a hero.

4) Mystique

Mystique is a major antagonist among the X-Men, and her ability to shapeshift makes it incredibly easy for her to deceive and betray others. For years, she’s operated secretly, often relying on betrayal simply to stay alive. She’s repeatedly betrayed characters like Wolverine, Sabretooth, and Rogue, and even the X-Men themselves, always prioritizing her own survival and that of her wife, Destiny. During the Krakoa era, her determination to resurrect Destiny led to extreme measures, including being double-crossed by Xavier and Magneto and unintentionally aiding the Orchis Initiative in creating Nimrod – all stemming from how she was treated. In many ways, this betrayal was justified, making it one of the few where her actions were understandable.

3) Professor X

Professor X, the founder of the X-Men, built the team on a hopeful vision, making his later betrayals all the more surprising. Throughout his history, Xavier repeatedly hurt those closest to him – from Gabrielle Haller, the mother of his son Legion, to Magneto and many others. He first earned the label of ‘X-traitor’ when revealed as the force behind Onslaught. He even enslaved the sentient Danger Room and erased the memories of the original second X-Men team from Cyclops and Moira MacTaggert. During the Krakoa era, he continued to betray his students, keeping secrets and ultimately falling under the influence of Mister Sinister. Kitty Pryde famously said Professor X was the worst, and he seemed determined to prove her right by betraying almost everyone he cared about.

2) Mister Sinister

Mister Sinister has a long history of betrayal, consistently deceiving his allies. For years, this didn’t bother the X-Men much because he primarily worked with other villains. However, things changed with the rise of Krakoa. Sinister’s vast DNA collection – originally created through manipulation by Professor X – became essential for mutant resurrection on Krakoa, earning him a position on the ruling Quiet Council. The X-Men suspected a trick and thoroughly examined the DNA library, but Sinister had secretly altered it. When he activated these changes, Krakoa transformed into a brutal mutant empire, one that even Sinister couldn’t manage, ultimately proving that his habit of betrayal backfired and ruined his own plans.

1) Beast

Hank McCoy, also known as Beast, was one of the original X-Men and was once known for his cheerful personality. But after years of hardship for mutants, he became more focused on practical results than optimism. He became involved with the Illuminati and made a dangerous decision to bring past versions of the original X-Men to the present, risking damage to the timeline. Things worsened during the Krakoa Era, driving him to believe that any action, no matter how terrible – including betrayal, genocide, and torture – was justified to protect mutants. Presumed dead, he has now returned, leading a group called 3K and working on a virus intended to transform all humans into mutants, hoping to end prejudice against this next stage of human evolution.

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2026-05-20 03:11