Fall of X

Fall of X is a Marvel Crossover comicbook event, created and published by Marvel Comics. Released to coincide with the 60th anniversary of X-Men, Avengers, and Iron Man, the crossover has prominent roles for all three.

Plot

Since their inception, the X-Men have fought for the rights of mutantkind, while also helping a human society that hates and fears mutants. But as threats to mutant existence have escalated, the X-Men have gradually taken a more militant stance, coming into open conflict with the Avengers twice.

To prevent future conflicts, Captain America forms the Unity Squad, comprised of Avengers and X-Men, to foster cooperation between the two teams. A major victory for mutant rights is achieved when the island nation of Krakoa becomes an official safe haven for mutants, maintaining a fragile peace with the other members of the United Nations. Every year, Krakoa hosts an event known as the Hellfire Gala, an official state dinner event where human and mutant minds convene.

Using their advanced technology, the mutants of Krakoa colonize the planet of Mars, which had recently been terraformed by the alien Ex Nihilo. This moves angers many other parties who had their own designs on the Red Planet, and as a counterreaction, former members of HYDRA, Advanced Idea Mechanics, and S.H.I.E.L.D. form the terrorist organization Orchis, which begins an intricate plot to discredit and destroy Krakoa.

You are cordially invited to the wedding of Tony Stark and Emma Frost

Meanwhile, Tony Stark has seen better days. Having divested himself from Stark Unlimited, he has nearly depleted his remaining fortune in a campaign to stop the arms dealing syndicate Source Control. Anticipating that another villain would attempt a hostile takeover of Stark Unlimited much like Obadiah Stane did in the past, Stark left primary ownership of the company in the hands of Zhong Wei, a trusted acquaintance he had befriended during the Armor Wars. However, Dr. Wei is murdered by Feilong, the Director of Operations for Orchis, giving Orchis control of Stark's company and technology. Using the resources of Stark Unlimited, Feilong creates the Stark Sentinels, a new breed of Sentinel with Iron Man's weapon and armor technologies. The Stark Sentinel prototype overpowers Iron Man's Model 70 armor, prompting the Armored Avenger to retreat and team with War Machine in an attempt to destroy the factory where the Sentinels are being created. They succeed, but this was only one of many factories where the Stark Sentinels are being produced. With the Avengers distracted by a False Flag Operation committed by agent provocateurs, Orchis unleashes a devastating attack on Krakoa, killing hundreds of thousands of mutants, forcing a small handful of survivors on the run.

As Iron Man joins the Hellfire Club (which his father was previously a member) to acquire the resources to defeat Feilong and the Stark Sentinels, Captain America assembles a new Unity Squad to avenge the mutants murdered by Orchis, and Doctor Doom offers asylum to any surviving mutant willing to serve in the Latverian army.

Meanwhile, the displaced previous leader of the Hellfire Club, Sebastian Shaw, seeks to reclaim his organization, and he has created his own Iron Man-inspired suit of armor, the Hellfire armor, to give him the edge.

Notes

• For much of Marvel's publication history, the Avengers have been neutral in the X-Men's fight for mutant rights. This event changes that, as Captain America, Iron Man, and Thor are openly fighting alongside their mutant allies.
• First appearance of the Model 72 armor.