As the founder of the X-Men, Professor Charles Xavier is the center of one of the longest-standing teams in the Marvel Universe. While he hasn't been acting quite like himself since he founded the nation of Krakoa, he is still directly responsible for creating a team that has saved the world and even the universe itself on numerous occasions.
Despite the best efforts of his students and his own mighty mutant powers, Xavier still hasn't always made it out of the X-Men's adventures alive. The X-Men are famous for dying and returning to life with alarming regularity, and Xavier himself is certainly no exception to that rule. Now, we're going to take a look back at all of the times Marvel almost killed Professor X off.
Battle with Grotesk
The first time Professor X seemingly died was in 1968's X-Men #42, by Roy Thomas and Don Heck. On a mission with the original five X-Men, Xavier seemingly met his end while attempting to stop the subhuman being Grotesk from using a machine to destroy the world. The machine exploded when Grotesk attempted to increase the power, and unfortunately both Grotesk and Xavier were caught in the blast.
Two years later, this death was revealed to not have been Xavier at all, but rather the shape-shifting Changeling posing in the professor's place. In reality, Xavier was working in secret beneath the X-Men’s mansion headquarters to enact a plan that would prevent an impending alien invasion.
The Brood Queen
At the conclusion of one of their first confrontations with the alien Brood, the X-Men suspect that Professor X has been implanted with a Brood egg. In Chris Claremont and Paul Smith's Uncanny X-Men #167, Kitty Pryde rushes to confront him but hesitates to act, reasoning that Xavier still looks human and has yet to begin to transform into one of the horrific aliens. However, her hesitation costs the professor his body, and he transforms into a Brood and attacks the X-Men in an instant.
The X-Men defeat the Brood/Xavier hybrid, and Xavier uses his dying breath to beg the X-Men to kill him before the Brood regains control. However, the X-Men instead elicit the help of Moira MacTaggert and the Starjammers, who transplant the professor’s mind into a newly cloned, Brood-free body.
Legion Quest
In the finale of the “Legion Quest” story, Professor X’s son, Legion, traveled back into the past in an effort to kill Magneto, reasoning that he could save Xavier's dream by killing Magneto before he becomes the X-Men's worst foe. As is often the case with plans of this nature, things don’t go exactly as intended in X-Men #41, by Fabian Nicieza, Andy Kubert and Ron Garney.
Legion succeeds in defeating Magneto, even though a team of X-Men traveled back in time in an attempt to stop him. But as he prepares to deal the death blow, Professor X protects his old friend and is killed in his stead. This death created the massively popular Age of Apocalypse timeline, and it wouldn't be undone until the end of that event.
Avengers vs. X-Men
During Avengers Vs. X-Men, Cyclops absorbed the absolute power of the Phoenix Force, only to be possessed and corrupted by its cosmic might. Taking on the combined forces of both the X-Men and the Avengers, Cyclops betrayed Emma Frost and stole her portion of the Phoenix, making himself the sole wielder of the power.
In Avengers vs. X-Men #11, by Brian Michael Bendis and Olivier Coipel, Professor Xavier attempted to stop his first student from allowing the power of the Phoenix from completely corrupting him, but even Xavier was no match for the unbridled power of the Phoenix. Cyclops unleashed the power of the Phoenix upon his former mentor, producing a psychic backlash that left the professor dead in the sand, and he would not return until another X-Men team rescued him from psychic limbo years later.
The Assassination on Krakoa
In House of X, Professor X returned with a new philosophy on how to approach the often torrid relationship between humans and mutants. With the help and influence of Moira MacTaggert, Xavier formed the first mutant nation on the island of Krakoa, uniting the majority of the mutant population.
This move immediately made many enemies of the human population, and several anti-mutant organizations were formed. One such organization, XENO, orchestrated a military assault against Krakoa that resulted in the professor being assassinated in Benjamin Percy and Joshua Cassara's X-Force #1. However, Xavier was subsequently resurrected by way of the island’s resurrection protocols, which bear a striking resemblance to the way that the Starjammers gave him a new lease on life years earlier.