Time and again the Uncanny X-Men have saved the world, and sometimes the universe, from the brink of extinction. Whether the threat comes from mutants, sentinels, humans or everything in between, you can bet the superhero team will be there to push back the darkness. With a long and complex history, the X-Men's roster has grown and shrunken, evolving constantly with every new age and team. In that time, with all the mutants who’ve found their way onto the team, you can bet things weren’t always hunky dory.

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When Professor Charles Xavier originally founded the X-Men neither he, nor anyone else, had the foresight to see that despite trying to make the world a better place, as the saying goes, the road to hell is often paved with good intentions. Playing out like a Shakespearean tragedy, the lives of the X-Men has seemingly been forever fraught with heartache, death, and betrayal. Though for our purposes we’ll be focusing on betrayal, and there has been a lot of betrayal, but redemption also never lingers too far away. Here at CBR we’re taking a look at 15 X-Men team members who, at some point or another, went on to betray either the team, themselves, and, sometimes indirectly, their entire race!

15 MAGNETO

The metaphysical rival to the brilliant Professor Charles Xavier, but also the enemy to his team of X-Men, Magneto has constantly danced around the borders of good and evil. Right and wrong are not cut and dry with the Master of Magnetism. After years of serving as the X-Men’s primary antagonist, Magneto experienced a change of heart after he nearly killed Kitty Pryde in battle.

Repenting for his sins, he joined the good guys; Professor X was out of action for a while and he attempted to fill the void. Despite his attempt, evil’s calling was too much and Magneto went right back to being a bad guy. Constantly going back and forth on the pendulum, one moment he was siding with the X-Men, then going against them; Magneto is always going to do what he feels is best for mutants everywhere.

14 BEAST

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After the event "Age of Ultron", time itself was splintered. The timestream was broken; the numerous irresponsible ways in which heroes and villains have traveled through time pushed the universe past it limits. Any further tampering with the timestream could literally rip time and space apart. Hank McCoy, Beast, did not care.

After Cyclops went a little crazy and started giving mutants a bad name, Beast struggles to think how he can fix the situation. He does the most reckless thing he can imagine: goes back in time to when the X-Men were just teenagers and brings them back to the present. He hopes it’ll fix things. It doesn’t. The team feels betrayed by Henry and the younger X-Men are trapped in today, unable to return home.

13 EMMA FROST

Emma Frost began her career as the White Queen of the Hellfire Club. An utter villain, she did everything possible to make the lives of the heroic mutants miserable. Yet she experienced a change of heart after her Hellions were killed in a Sentinel attack. After that, she joined the X-Men, added a new wing to Professor Xavier’s school and serving as an instructor for the first Generation X team.

Despite them eventually abandoning her, Emma stayed with the X-Men where she had an affair with Cyclops, behind Jean’s back. That wasn’t enough to kick her off the team however. She remained a steadfast companion to Cyclops, helping him lead the team. Even after getting possessed by a portion of the Phoenix force and trying to take over the world, Emma really turned bad when she orchestrated a war between the X-Men and Inhumans -- then decided to just kill everyone.

12 BISHOP

Bishop, similar to Cable (and dozens of other X-Men at this point) comes from a dystopian future where the Sentinels have taken over the world, rounding up humans and mutants alike and branding the letter M on the latter’s face. Even with his energy absorption powers, Bishop could do little in the face of such overwhelming odds.

Time-traveling back to the present day to prevent a traitor from later disbanding the X-Men, Bishop infiltrated the team. He constantly kept a lookout as to whom the traitor might be, ready to act so as to prevent the future he came from. Yet along the way, Bishop went several kinds of crazy in his methodology. He tried killing Hope, the “Mutant Messiah,” only to then accidentally “kill” Professor Xavier, and then later kill Cable. These days Bishop is back in the present and trying to redeem himself.

11 MYSTIQUE

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Mystique is something of an on oddball here, as she and Sabertooth both started their careers as pure evil. You wouldn’t think there was a decent bone in her body, so when Rogue recruited both her and Sabertooth for the rapid response unit Cyclops insisted she build, eyebrows were raised. In typical X-Men fashion, things didn’t last long for Mystique, but it wouldn’t be the last time she’d try to be a hero.

She also helped Magneto against the Red Skull during "Axis", when the Nazi supervillain turned all the heroes evil and the bad guys good. After Magneto and company won, the spell was reversed and Mystique became wicked again. In Cullen Bunn’s Uncanny X-Men series, Pyslocke recruits a new team, acting in a similar way to Rogue’s original group, as a clandestine response unit. Bringing in Mystique, the shapeshifter is able to do some good in the world.

10 RACHEL SUMMERS

Rachel-Summers

Rachel Summers, arguably the most powerful member of the Summers family, possesses a history akin in complexity to a map of Willy Wonka’s Chocolate Factory. The daughter of Cyclops and Jean Grey from an alternate timeline, Rachel also comes from a future where mutants have been hunted to the brink of extinction. Rachel’s betrayal of her fellow man began in this nightmarish dreamscape of an existence.

Endowed with incredible abilities, i.e. telekinesis, telepathy, when Rachel was a child in her timeline, the X-Men headquarters at Xavier’s School of Gifted Youngsters was attacked. One of the only survivors, Rachel was taken, drugged in order to suppress her psionic abilities, and then turned over to the cruel Ahab, who tortured and brainwashed her. Ahab turned Rachel into his personal attack dog, calling her “Hound”, putting a leash on her, and forced Rachel to use her powers to hunt down other mutants.

9 GAMBIT

Gambit

Extremely popular, especially in the early '90s, the Cajun mutant card-player always had a trick up his sleeve. Brought up by a thief’s guild and master manipulators, Gambit’s early life wasn’t full of ice cream and lollipops. Despite joining the X-Men, trouble had a nasty habit of following him around, especially when Mr. Sinister wanted to collect on a debt Gambit owed him.

Gambit fulfilled his obligation to Sinister, but it ended up only aiding the Marauders in killing hundred of mutants. Gambit concealed this particular stain in his ledger for a while, but then Apocalypse showed up and turned Gambit into one of his Horsemen. Gambit broke free of his control thanks to Sunfire, but Sinister once again found a way into manipulating Gambit into committing evil deeds. Since then, Gambit is trying to live a simple and joyous life as a carefree thief.

8 JEAN GREY

Jean Grey Dark Phoenix Tylery Kirkham

Aside from Wolverine, Jean Grey is by far none the most popular X-Man. Gorgeous, willful, kind, and mighty, Jean Grey has proved her mettle repeatedly in the fire of battle. Whether it’s her older self or her younger time-displaced iteration, Jean consistently served as a cornerstone for the rest of her teammates -- there is nothing they would not do for her.

Jean on the other hand, when possessed by the Phoenix, was more than okay with killing them. Okay, that might not be entirely true, but after destroying a planet, there’s not a lot of wiggle room for morality. Completely out of her mind, Jean would totally have killed her friends, and probably the Earth, without a second thought if not for the deus ex machina problem-solving skills of comic books.

7 SUNFIRE

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Japan’s pride and joy, Sunfire is the country’s personal superhero. Joining up with the X-Men in the team’s relatively early days, Sunfire didn’t stick around too long, but he remained a hero for years. When Sunfire lost his powers to Rogue, things took a gloomier tone for the superhero, as the deadly Lady Deathstrike would slice his legs off soon thereafter.

Like many other lost X-Men, Apocalypse found a way to influence the broken Sunfire, promising the mutant new legs and more power should he be the Apocalypse‘s Horseman of Famine. Of course Sunfire ended up getting swindled and would join Gambit with the Marauders, which led him to battle the X-Men a couple times. Not to worry, Sunfire was eventually restored to normal, but the damage had been done. We haven’t seen much of the Japanese hero recently.

6 ANGEL

Often considered a shining beacon of hope and optimism, Angel was one of the founding members of the first X-Men team. His good-natured personality was only further accentuated by his angelic looks, one of the primary reasons for his moniker. Like every other X-Man in the history of comics, Angel’s story ran into a brick wall when he was tortured, had his wings amputated, and then lost his private jet.

In this moment of weakness, the mutant Apocalypse approached Angel, promising the young mutant a new pair of shiny wings. True to his word, Apocalypse gave Angel new wings -- metal ones that could shoot poison-tipped feathers. Alas, Angel also became his Horseman of Death and attacked the X-Men constantly. Even after breaking free from Apocalypse, the new Archangel would constantly have murder on his mind.

5 PSYLOCKE

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For the majority of her occupation as a superhero, except for the beginning that involved large amounts of body-swapping and mind-control, Betsy Braddock, has been a solid and absolute constant on the X-Men team. Armed with deadly psychic knives, crazy skills in martial arts, and her other psychic abilities, Psylocke proved herself a valuable ally repeatedly. Until she wasn’t.

During her tenure as the leader of Cyclops’s black ops mutant hit squad X-Force, the psychic mutant was forced to make some questionable choices. It wasn’t so much Psylocke’s choices that betrayed her teammates, as someone was needed to step up and make the hard calls, but the cavalier attitude with which she would read a teammate’s mind, invading their most personal space. It ultimately felt like a harsh show of unfaithfulness.

4 SABERTOOTH

Sabretooth from X-Men

Wolverine’s arch-villain for his entire life, Victor Creed, Sabertooth, was and is a merciless murder machine of a mutant. The dark mirror of Wolverine’s reflection, while Logan learned to tame the beast within, Victor embraced it and would laugh all the while as he bathed in the blood of his victims.

Yet despite all the horror he’s caused, Rogue still gave the mutant sanctuary when he was fleeing from being hunted. Bringing him onto the X-Men. Wolverine, when he found out, wouldn’t put up with such brash nonsense and killed Sabertooth. Though like a bad penny, Sabertooth came back. With that out of the way, he went running around with Mystique causing all sorts of crimes. Yet during "Axis", he got turned good, and has strove to fight the beast within.

3 WOLVERINE

Wolverine

While Logan, aka Wolverine, one of the baddest mutants around, might be made of adamantium, cigars, and hard liquor, but his penchant for violence has gotten the feral mutant in trouble multiple times. He’s already prone to violent outbursts, what with his ordeals with Weapon X. Wolverine’s temperament, along with his wide range of deadly skills and incredible mutant abilities, make him a prime candidate for manipulation and mind-control by bad guys.

Logan has inadvertently betrayed the X-Men and the rest of the world, multiple times. He’s been turned into Apocalypse’s Horsemen of War, Hydra has mind-controlled him into attacking his friends and family, and in "Old Man Logan", when the villains of the world united, Wolverine was tricked into killing all the X-Men. It’s not easy being the best there is at what you do.

2 COLOSSUS

All in all, the kind-hearted Russian mutant Colossus is pretty much the last guy you’d think would betray his friends and colleagues, but death has a way of changing a guy’s personality. When the Legacy virus killed his sister Illyana and then his parents were horribly murdered shortly thereafter, it was a little too much for the noble Colossus to bear.

Clearly not thinking straight, Colossus joined Magneto’s Acolytes, turning his back on the X-Men. It was a dark, and thankfully, short time for the metal mutant and he’d come to his senses and join Kitty Pryde on the Excalibur team. Colossus would betray the team, and the rest of the world, again when he inherited a portion of the Phoenix Force. It drove him mad as he, and the rest of his Phoenix Force brethren, tried taking over the world and remaking it in their personal image.

1 CYCLOPS

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The X-Man who’s lead his team of vagabond mutants more times than anyone can count, Scott Summers is a staple of the X-Men comics. The first student under Charles Xavier, Cyclops trained to be the best and the best he became. With an impressive mind for tactics, Cyclops carefully detailed all his plans, which in turn helped his team win fight after fight.

Yet for all the good he’s done, things got darker for Cyclops once he assigned teenage mutants to act as his personal hit squad. From there, the Phoenix Force possessed him and some fellow mutants, but he killed Professor X, while they merely tried taking over the world. Afterwards, Cyclops broke out of prison, and he took a militaristic approach in dealing with humans, making the world extremely uncomfortable as he nearly set off a war between humans and mutants.

Are there any other X-Men that betrayed their team and race? Let us know in the comments section!