The X-Men rose from obscurity to the top of the Marvel Universe. They've been Marvel's bestselling comics for years, and there was a time when the X-Men's events were the center of Marvel's publishing schedule. The X-Men fell from grace for a time, with almost fifteen years of editorially mandated stagnation, but they've come roaring back during the Krakoa Era. Since then, the X-Men have gone back to being Marvel's hottest property.
Over the years, the X-Men have had many big event stories that are very important to the team's development. The X-Men and change go hand in hand, and the most important X-Men events have let the team evolve into something new. Anything can happen during an X-Men event, which is why fans love them so much.
10 Powers Of X
By Jonathan Hickman, R.B. Silva, Adriano Di Benedetto, Marte Gracia, and Clayton Cowles
Powers of X showed readers alternate realities, although that wasn't clear right away. At first, the book seemed like a companion piece to House of X, showing readers the past and future for Marvel's merry mutants. However, Moira MacTaggert's secret was revealed in HoX, PoX's true shape became known and readers got to see two different futures from two of Moira's lives.
Powers of X wasn't as groundbreaking as its sister book, but it's still extremely important to the overall story of the Krakoa Era, thanks to revealing the important events in the past that helped Krakoa become a reality. It also highlighted two terrible futures that underlined the tragedy of mutantkind: that mutants always lost. It's an amazing book that's much more important than its reputation as a supplementary book makes it seem.
9 X-Men: The Twelve
The '90s were an interesting time for the X-Men. The books sold like hotcakes, to the extent that X-Men comics kept Marvel going as the company's financials cratered. The art was gorgeous even after the Image founders left, but the stories don't get a lot of love. A big reason for this was that there were so many long-term plots with no resolution, something that frustrated readers to no end. As the decade closed out, though, it was time for answers.
X-Men: The Twelve was a crossover event that ran through Uncanny X-Men, X-Men, Wolverine, X-Men, and Cable, pitting the X-Men against Apocalypse as his plans for obtaining godlike power came to fruition. The story revolved around the mystery of the Twelve, who they were, and why Apocalypse wanted them. This story has a mixed reputation, but it closed out the '90s in epic fashion, wiping the slate clean and readying the X-Men for the new millennium.
8 Mutant Massacre
Mutant Massacre was the big summer crossover of 1986, running through Uncanny X-Men, X-Factor, New Mutants, Thor, Power Pack, and Daredevil. The Morlocks were a group of mutants whose powers changed their appearances, forcing them to live underground. Mutant Massacre featured Mister Sinister sending the Marauders into the sewer tunnels of Manhattan to slaughter the Morlocks, who Sinister felt were genetic dead ends.
The X-Men and their allies spring into action, but the fight went badly for several members of the team. The biggest loss involved the Angel's wings being cut off. Mutant Massacre reminded readers how dangerous being a mutant could be and heaped change upon the X-Men and their allies in a way that wasn't prevalent at Marvel at the time. It was also the first time the X-Men headlined Marvel's big summer crossover, something that would happen several more times in coming years.
7 Inferno (2022)
By Jonathan Hickman, Valerio Schiti, Stefano Caselli, R.B. Silva, Adriano Di Benedetto, David Curiel, and Joe Sabino
Jonathan Hickman leaving the X-books divided the fanbase. Some fans were okay with it, some were angry about it, and some were completely indifferent. Hickman's last X-Men story was Inferno, a story which heavily dealt with the mutant triumvirate of Xavier, Magneto, and Moira MacTaggert and the machine duumvirate of Nimrod and Omega Sentinel.
In the middle of all of that, Mystique resurrects Destiny, and Xavier and Magneto let Emma Frost in on Moira MacTaggert's secret. These events put them all on a collision course, with an ending that changed the Krakoa Era going forward. The one-two punch of Hickman leaving and massive change to Krakoa make this event very important to X-Men history.
6 Fall Of The Mutants
By Chris Claremont, Marc Silvestri, Dan Green, Glynis Oliver, and Tom Orzechowski
Fall of The Mutants is an odd event. It crossed through all the mutant books of 1988, however saying it "crossed" is incorrect. Fall of The Mutants had no overarching story. Instead, it was about each mutant team encountering a situation that would break them and change. Uncanny X-Men #225-227 was the most important part, as the X-Men went to Dallas, Texas to discover why Destiny said she foresaw their deaths there.
This led them to Forge and his enemy, the Adversary, a powerful magical enemy from Indigenous legend. The X-Men succeeded in their battle against the Adversary, but faked their deaths by walking through the Siege Perilous. Merlin's daughter Roma made them invisible to cameras and surveillance equipment, and they'd make their base in Australia, kicking off the Outback era of the X-Men.
5 Inferno (1989)
Inferno is an '80s X-Men masterpiece. Marvel's big 1989 summer crossover, it ran through Uncanny X-Men, New Mutants, X-Factor, X-Terminators, Excalibur, Avengers, Daredevil, Power Pack, Fantastic Four, Spectacular Spider-Man, Amazing Spider-Man, Web Of Spider-Man, and Damage Control. The story revolved around S'ym and N'astirh of Limbo teaming with Madelyne Pryor to invade the Earth, starting with New York City.
The X-Men comics were the bestselling Marvel comics by 1989, so having them be the center of the publisher's biggest crossover that year was a no-brainer. This story ended the Madelyne Pryor subplot that had been running through the X-Men books and set the X-Men comics in new directions. However, this was the first linewide X-Men crossover, making Mutant Massacre look quaint by comparison.
4 Days Of Future Past
By Chris Claremont, John Byrne, Terry Austin, Glynis Wein, and Tom Orzechowski
Days Of Future Past set a terrible precedent for the X-Men books. This story took readers to a horrifying alternate reality, one where the Mutant Registration Act had led to the rise of Sentinels. Soon, these mutant-hunting machines would kill all the superheroes and take over the world, with only a small group of X-Men standing in their way. The team sends Kate Pryde into the past, taking over her younger body so she can help the X-Men foil the assassination of Senator Robert Kelly, the event that led to the MRA passing.
This story isn't an event like modern readers understand them, but a two issue story running through Uncanny X-Men #141-142. However, its introduction of a future controlled by Sentinels became a key part of X-Men mythology. It's basically the default future of the X-Men. Any alternate future stories that came after drew inspiration from this X-Men classic.
3 The Dark Phoenix Saga
By Chris Claremont, John Byrne, Terry Austin, Bob Sharon, and Tom Orzechowski
Running through Uncanny X-Men #129-138, The Dark Phoenix Saga is an undisputed classic. The story of the fall of Jean Grey into the Dark Phoenix is a tale full of pathos and action, as the X-Men battle their most beloved friend. It pays off over two years of stories, and readers still talk about The Dark Phoenix Saga's shocker of an ending decades later.
The Dark Phoenix Saga closed out the Phoenix storyline in epic fashion. It signaled a turning point in the history of the X-Men and helped cement the Phoenix Force's place in the history of the Marvel Universe. This story is the best of the best.
2 House Of X
By Jonathan Hickman, Pepe Larraz, Marte Gracia, and Clayton Cowles
House of X was revolutionary. After years of Marvel marginalizing the X-Men because Disney didn't own their film rights, the purchase of 20th Century Fox brought the mutants home. Marvel pushed the X-Men again, and they did that by getting Jonathan Hickman to come up with an entirely new status quo for the X-Men, kicking off the Krakoa Era.
House of X revolves around the establishment of the mutant nation of Krakoa, Moira MacTaggert's secret, and the X-Men's battle against the Orchis Initiative. It kicked off an entirely new era of the X-Men, immensely changing the status quo. On top of all of that, it's a brilliant story.
1 The Age Of Apocalypse
The Age of Apocalypse has aged gracefully. Fans didn't know how to react when Marvel announced that the X-Men books were being canceled and replaced in 1995. What readers got was the best alternate universe story in Marvel history. The accidental death of Professor X at Legion's hands created a timeline where Apocalypse conquered North and South America and started a genetic war.
The Age of Apocalypse is a classic. It shook up the sometimes staid X-Men tales of the '90s and gave readers some classic redesigns of their favorite characters. It also put Apocalypse on the map, making him the Thanos of Marvel's mutant comics. Running through nine miniseries and two bookend issues, The Age of Apocalypse proved itself to be an epic unlike any other.