Merge:Planet X

Planet X was the name of the seventh storyline in Grant Morrison's run on the Marvel Comics X-Men title New X-Men. It was preceded by Assault on Weapon Plus and followed by Here Comes Tomorrow, with the latter serving as the coda to Morrison's run.

Plot
Xorn revealed that he was Magneto in disguise (becoming referred to as "Xorneto" by comic book fans) and that he had worked to undermine the X-Men ever since joining them:

Magneto had taught anti-human philosophy to students at the Xavier Institute and dealt the mutant-power enhancing drug Kick, helping to cause Quentin Quire to incite the riot at the X-Mansion and kill off Sophie of the Stepford Cuckoos. It was also hinted that Magneto was the mole in the institute providing information to the Weapon program. Esme of the Cuckoos, without Sophie there to stop her, was then seemingly able to kill Emma Frost, which in turn caused Cyclops to run away from the Institute after his affair with Emma had been discovered. He then joined Wolverine and Fantomex in a search for the Weapon Plus headquarters. After the Weapon Plus space station Cyclops, Wolverine, and Fantomex had found exploded, Professor X sent Jean Grey, Beast, and the restored Emma Frost to rescue them. Magneto was then able to capture Professor X without any inteference from the X-Men.

Magneto revealed that he had not actually healed Xavier's legs, but rather had been keeping Xavier up with magnetic control over nanobots in Xavier's bloodstream. Magneto then took over New York City, and surrounded himself with his mutant followers, both former members of the Brotherhood of Evil Mutants, as well as teenagers from the Xavier Institute. Magneto planned to reverse Earth's magnetic field and remake the planet as "Planet X" in which mutants, the possessors of the "X-gene", ruled over ordinary humans.

In the end, Magneto was defeated, but only after he had destroyed the X-Mansion and devastated New York City. Wolverine decapitated Magneto after Magneto killed Jean Grey. The end of the story jumps forward 150 years in time to a place on the moon, where an astronaut finds something called, "the Phoenix Egg."

Major consequences

 * Xorn was revealed to be Magneto (later retconned to be an impersonator).
 * Jean Grey was killed by Magneto.
 * Magneto was killed by Wolverine.
 * Humans became even less trusting of mutants in the wake of the extensive damage to New York City.
 * Esme of the Stepford Cuckoos was killed by Magneto, leaving them the Three-in-One.

Behind the scenes
Grant Morrison had intended Xorn to be the real Magneto. However, Marvel reversed several of Morrison's decisions after the "Planet X" arc, reconstructing the school immediately and reintroducing Magneto (in Chris Claremont's new Excalibur book), establishing that Magneto had never left Genosha after its destruction. Marvel also introduced a new Xorn (in Chuck Austen's X-Men), establishing that the new Xorn was the brother of the original and that the original had been possessed by some (unrevealed) force, widely believed to be Sublime, a conscious, highly evolved and intelligent bacteria colony. Some confusion has arisen, however, due to the somewhat chaotic way Marvel went about these reversals, in two separate comics, and without providing complete answers as of yet. Morrison has expressed surprise due to the various retcons and explanations for the events of the story that emerged after his departure from Marvel. In exasperation during an interview, Morrison said "Here's how to explain what happened - XORN was NEVER REAL, he was a DISGUISE for MAGNETO who went MAD ON DRUGS and DIED...but we know he always COMES BACK, somehow, so expect a dramatic return sooner or later, True Believers!"

A number of X-Men readers have indicated strong feelings for and against these changes on various comic book message boards. Grant Morrison fans have posted complaints about what they see as Marvel maliciously unwinding Morrison's story. Just as many X-Men fans, however, believe that Morrison's portrayal of Magneto, a character who is a Jewish Holocaust survivor, as a Nazi-like dictator who would herd people into crematoriums, was equally malicious.

When asked to comment on this, Grant Morrison responded: "What people often forget, of course, is that Magneto, unlike the lovely Sir Ian McKellen, is a mad old terrorist twat. No matter how he justifies his stupid, brutal behaviour, or how anyone else tries to justify it, in the end he's just an old bastard with daft, old ideas based on violence and coercion. I really wanted to make that clear at this time." Morrison also stated that the arc was intended as a statement on the rigidly elastic nature of the status quo in franchise comics, and that the arc had taken such dark leanings because of "loved ones dropping like flies" at the time of writing.