Charles Xavier created the X-Men for two reasons. One was to teach young mutants how to use their powers safely. The second was to create a team that could act as heroes to ease the relationship between mutants and the humans who fear them. However, there are several X-Men who have been anything but heroic in their lives.
The X-Men have always had to battle with anti-mutant bigotry, and this has caused some of them to act like the villains they usually fight. The mutants have cheated, stolen, killed, and broken all kinds of laws, things they could usually set out to bring down villainous mutants for doing. At the end of the day, they are still heroes, but many X-Men members have been one step away from turning to the dark side.
Beast was, at one time, a loveable and enthusiastic founding member of the X-Men. However, he grew darker as time went on. There was even an alternate world’s version of Beast, known as Dark Beast, who conducted disturbing and unethical experiments, having turned completely evil.
The main timeline Beast is getting close to that in Krakoa. He has committed many crimes and simply told Professor X not to ask questions he doesn’t want answers for. Beast has also become ruthless, sending mutants to their deaths and explaining his actions by saying they can be resurrected, ignoring the pain he is putting them through. There might not be a more immoral X-Men member in Krakoa right now.
Magneto started out as the X-Men’s archenemy along with the Brotherhood of Evil Mutants, so it is no surprise that he has done a lot of terrible things over his career. However, he has also joined the X-Men and served as their leader on several occasions. In the 1980s, he took over as the leader when Charles Xavier left Earth, but then reverted to a villain after that.
Currently, Magneto is a hero once again, serving on the Quiet Council in Krakoa. He is one of the only people other than Charles Xavier to know the secret behind the new mutant society. However, Magneto is also not above turning back the clock. He has betrayed almost every other mutant on the X-Men team and, in his most villainous moment, ripped the adamantium from Wolverine’s skeleton.
Professor X is supposed to be the man who set the template for how all mutants should act. The problem is that Xavier has not always practiced what he preached. As the X-Men’s main leader, Charles Xavier has done more villainous things over his life than most of the X-Men combined.
He manipulates the mind of anyone he wants, even completely rearranging the memories of Wolverine to force him to join the X-Men in the first place. He joined the Illuminati, which was responsible for pulling strings behind the backs of all Earth’s heroes. He shut down Magneto’s brain once, which unleashed the monster Onslaught into the world. Even now, as the main man in Krakoa, he has manipulated the world to bow to his country’s whims.
Emma Frost was another villain who later became a member of the X-Men. When she joined, it was because she realized that Charles Xavier’s ideals were the right ones, and she soon became a trusted ally. She even romanced Cyclops at one point, and the two led the X-Men to great heights.
However, while leading the X-Men, she did something unforgivable. She faked Cyclops’ death to send the mutants into a war with the Inhumans. Her actions caused many mutants and Inhumans to almost lose their lives, and she went on the run when both sides learned the truth.
When Wolverine joined the X-Men, he was fresh from working for a secret government agency in Canada, and before that, he was part of the Weapon X program in the United States. After Wolverine joined the X-Men, he did everything he could to transition into a hero and curb his violent streak.
However, Wolverine has crossed the line more than once. He killed his own son Daken when he learned that Daken was fated to do terrible things in the future. In “Age of Apocalypse,” one of the most destructive alternate X-Men timelines, Wolverine became the ultimate evil dictator. In the “Old Man Logan” storyline, he killed every member of the X-Men.
Cyclops committed the ultimate sin when he was a leader in the X-Men. He murdered his mentor and father figure, Professor Xavier. This happened in Avengers vs. X-Men and it happened because Cyclops and his teammates wanted to allow the Phoenix Force to return to Earth, with him and several teammates possessed by it.
When Professor X tried to end the war between the two teams, Cyclops murdered him in cold blood. Cyclops then lost the Phoenix Force and went to prison, where he ended up as a martyr to disenfranchised mutants all over the world.
Out of all the members of the X-Men, the one who committed the most heinous atrocity was Jean Grey, the former Marvel Girl. Jean was a founding member of the team and was its heart and soul for many years. However, after a mission in space went wrong, she returned to Earth with the Phoenix Force controlling her.
This is when Jean committed the ultimate sin. With the Dark Phoenix rising inside her and the Hellfire Club pushing her to the brink, Jean set out and destroyed an entire galaxy. Billions died in the attack, and Jean ended up giving her own life to atone for this villainous act.
Angel was the one X-Men member that seemed to seem the least likely to ever become a villain. Not only was he an “angel” with big, white wings allowing him flight, but he could hide the wings under a shirt and go on as if he was a non-mutant human. This changed after Angel was attacked and lost his wings.
In what readers thought was Angel taking his own life, his close friend Cameron Hodge betrayed him and blew up a helicopter he was on. Apocalypse brought him back as Archangel, and Angel had a change of heart. More than once, Archangel murdered anti-mutant terrorists in cold blood, stepping over a line that the X-Men swore never to approach.
Rogue started out her career as a villain. Rased by Mystique and Destiny, she was a villain who battled the Avengers. She actually used her mutant abilities to strip Carol Danvers of her Captain Marvel powers and much of her memory, destroying the superhero’s life for many years.
After becoming a hero, Rogue changed and atoned for those sins. However, there was a point when she stepped over the line. On a new team of X-Men and Avengers members, Rogue found herself teaming with Scarlet Witch, who has previously stripped most mutants of their powers. At one point, Rogue mistakenly thought Scarlet Witch betrayed them, and with no evidence to back it up, she murdered Wanda in cold blood.
Gambit did one of the most villainous things in X-Men history, and he didn’t even know he was doing it. Mister Sinister had built up a group called the Acolytes and forced Gambit to help him. Without knowing the reason for it, Gambit helped lead Sinister’s team into the tunnels under New York City.
This is the event that led to the Morlock Massacre. Gambit realized what he did and hid it from his teammates, even his lover, Rogue. When the X-Men learned he was responsible, they banished him from the team.