Spoilers for AXE: Judgment Day #4 follow!
AXE: Judgment Day #4 included a shocking death in the X-Men world. Shocking deaths sadly dominate the X-Men's history in Marvel Comics, with teammates, friends, and enemies all falling in unexpected circumstances. These tragic deaths not only mark X-Men comic book history, but they likely also forecast their eventual MCU destiny.
The greatest X-Men stories feature unforeseen sacrifices but the most shocking deaths often occur during stories where the stakes don't hint at such an outcome. They also often befall beloved characters or even brand-new ones, dashing fan expectations before they get an opportunity to truly solidify.
Magneto
Once among the best X-Men villains ever, Magneto heroically gives his life in AXE: Judgment Day #4, fending off the Eternals on Arrako. Already grievously wounded by Uranos, Magneto falls after using his magnetic power to turn the Eternals' machines against them. The fall of a mutant icon becomes even more profound considering this one may be permanent.
Magneto declined to participate in the Krakoa Resurrection Protocols that have given mutants effective immortality. He deleted the one copy of his backed consciousness on Cerebro, meaning his death is likely irreversible, at least by the means fans expect.
Professor X
Comic book fans know Professor X has died a time or two in his tenure with the X-Men. Perhaps the most shocking death came at the most unexpected time. 2019's X-Force #1, launched just after the House of X miniseries reset the mutant status quo, ended with the mutant leader brutally assassinated on Krakoa.
The unexpected death at the outset of this new era surprised many but also reinforced the new rules for the X-Men. Death shifts in its power and meaning, with many X-Men dying many times already since the Resurrection Protocols were put into place.
The Scarlet Witch
The Scarlet Witch's erasure of most mutants in existence in House of M provided many suspects for her murder in The Trial of Magneto, but her death still proved shocking. Among the most powerful magical beings in the Marvel Universe, few people on Krakoa could kill her or would even try.
Her death ultimately proved more surprising than it initially appeared after it was revealed that she orchestrated her own death to help bring back mutants who died before the protocols were activated. By going through the resurrection process herself, she created a mutant afterlife beyond space and time.
Blink
Blink dies in X-Men #37, just a few short issues after her debut in Uncanny X-Men #317. She heroically sacrifices her life saving her fellow young mutants from the Phalanx, but she built up enough fan appreciation in her short comic book career to leave readers wanting more.
An alternate-reality Blink returned in Age of Apocalypse, among the best X-Men comic book storylines ever. She later joined the Exiles team, traveling through the multiverse on adventures that likely bring her to the MCU thanks to its unfolding Multiverse Saga.
Courtney Ross
Courtney Ross appeared to be a key supporting character in Excalibur when the book debuted in 1988. But in issue #5, she died shockingly at the issue's end. Even more shocking, her own evil variant, Opal Luna Sat-Yr-9 (Saturnyne) killed her and took her place without anyone realizing the truth.
Courtney's death proved especially bitter for prospective fans, as she had just overcome Arcade and his Murderworld, and was poised to become a fun, vital part of Excalibur's world.\
Moira MacTaggert
Few twists in X-Men history rival the reveal that Moira MacTaggert was a mutant all along. Her death led to the shocking revelation that Moira had died many times before and carried over memories from each life. This allowed her to try and engineer a path for mutant survival into the far future, with varying results.
Her death and secret power completely upended the mutant status quo, leading to the experiment on Krakoa and the current war between the Eternals and X-Men, with humanity caught in the middle.
Madelyne Pryor
Madelyne Pryor effectively replaced Jean Grey in the comics, so much so that Cyclops left her in a disgraceful moment when Jean Grey returned. That doesn't make her death any less shocking or tragic. Madelyne died during Inferno after she transformed into the Goblin Queen and tried to destroy the world.
Mister Sinister cloned her from Jean Grey and manipulated her into turning evil, further complicating her character. Madelyne clones still exist in the comics and so does the threat that the Goblin Queen returns.
The X-Men (Fall Of The Mutants)
The entire X-Men team appears to die in The Fall of the Mutants, a major crossover event from the late 1980s. The team collided with forces beyond their control after the Mutant Registration Act becomes law. They meet their fate however through unlikely circumstances when Forge casts a spell to kill a demon he once summoned to save his friends in Vietnam.
This spell kills the X-Men instantly but Roma, a powerful mystical entity from Otherworld, intervenes. She brings them back to life but maintains the illusion that they died, as their sacrifice had a major impact on the perception of mutants in America.
All The X-Men (Old Man Logan)
The X-Men die for real in Old Man Logan, set in one of the darkest future timelines in Marvel Comics. Wolverine kills the entire team in a blind rage induced by Mysterio. Before Logan realizes what happened, he's massacred his friends and colleagues. This leads to a dystopian future with few heroes at all.
The X-Men's shocking death in this alternate reality mirrors their fate in others, such as Days of Future Past. In that dark timeline, Sentinels killed virtually the entire team, including Wolverine.
Thunderbird
X-Men fans know Blink wasn't the first new recruit to die right after joining. Thunderbird helped found the All-New, All-Different team in Giant-Size X-Men #1 in 1975. Two issues later, in X-Men #95, he died in shocking fashion. Thunderbird jumped on the plane that Count Nefaria escaped in after a battle, but the plane exploded, killing the mutant.
Thunderbird's tragic end proved a sober reminder of how dangerous life for mutants could be. It also represented a rare permanent death in comic books, with the character remaining dead until just recently when the Scarlet Witch's actions on Krakoa made it possible for him to return.