History ComicBook / Onslaught

* EnemyWithin[=/=]EnemyWithout: Xavier's evil side had already manifested in physical form once before in the ''X-Men vs Franchise/{{Micronauts}}'' series.

* ArcWelding: The opening of ''Onslaught: X-Men'' does this to the traitor tape that was a part of Bishop's backstory, revealing that Jean sent it after Onslaught attacked X-Men--and hence that the X-traitor was none other than Professor X himself, not that he was the first to die (while he didn't die, either, Jean believed it was Juggernaut). The story also had Onslaught use an element from the early comics ([[TeacherStudentRomance Professor Xavier having the hots for Jean]]) to try to lure Jean to his side.
* AWizardDidIt: Though other mutant heroes couldn't enter Onslaught's field (they'd get possessed) the Avenger's Scarlet Witch was able to make an exception for herself with her powers.

[[quoteright:250:http://static.tvtropes.org/pmwiki/pub/images/onslaught_001.jpg]]

* GenreSavvy: None of the heroes are dumb enough to blindly trust Doom, but the more pressing threat keeps them distracted. Iron Man and Hawkeye, however, stay focused and are ready when Doom tries something.

* CapcomVsWhatever: Onslaught served as the final boss of the first Marvel Vs. Capcom game, where he was the resident SNKBoss.

''"Know my name and fear it! I am Onslaught!"''

Thanks to the [[ComicBook/RedSkull Red Skull]]'s clone grafting Professor X's brain onto his own, and Magneto subsequently crushing his head in, he became Red Onslaught, kicking off the Autumn 2014 event ''ComicBook/{{AXIS}}''.

* DangerouslyGenreSavvy: Onslaught knows everything Xavier knows, meaning he can anticipate how many of the various heroes will act.

* WouldHurtaChild: Apocalypse's idea to end the crisis was to kill Franklin Richards. Needless to say both Cable and [[MamaBear the Invisible Woman]] put an end to that plan.

* Would Hurt a Child: Apocalypse's idea to end the crisis was to kill Franklin Richards. Needless to say both Cable and [[MamaBear the Invisible Woman]] put an end to that plan.

* WouldHurtaChild: Apocalypse's idea to end the crisis was to kill Franklin Richards. Needless to say both Cable and [[MamaBear the Invisible Woman]] put an end to that plan.

** ComicBook/{{Apocalypse}} does try to help against Onslaught, though Cable and the Invisible Woman stops him from trying to kill the latter's son.

* EvenEvilHasStandards: Despite the fact his method involve murdering a child, even ComicBook/{{Apocalypse}} is horrified by Onslaught's actions.

** It becomes unintentional FridgeBrilliance after TheReveal of Onslaught's identity: If you become evil and all-powerful, one of your first targets would be the invincible-til-now man who has bullied and tried to kill you from childhood to the present day.

* EnemyMine: Doom sides with the heroes and helps them against Onslaught. When he tries to collect an energy sample for his own ends, though, Hawkeye and Iron Man take him down.

* ArcWelding: The opening of ''Onslaught: X-Men'' does this to the traitor tape that was a part of Bishop's backstory, revealing that Jean sent it after Onslaught attacked X-Men--and hence that the X-traitor was none other than Professor X himself, not that he was the first to die (while he didn't die, either, Jean believed it was Juggernaut). The story also had Onslaught use an element from the early comics ([[TeacherStudentRomance Professor Xavier having the hots for Jean]]) to try to lure Jean to his side.

* ArcWelding: The opening of ''Onslaught: X-Men'' does this to the traitor tape that was a part of Bishop's backstory, revealing that Jean sent it after Onslaught attacked X-Men--and hence that the X-traitor was none other than Professor X himself, not that he was the first to die (while he didn't die, either, Jean believed it was Juggernaut). The story also had Onslaught use an element from the early comics ([[TeacherStudentRomance Professor Xavier having the hots for Jean]]) to try to lure Jean to his side.

The X-Men suffer several attacks by minions of the seemingly omnipotent entity known only as "Onslaught", who appears to know them well. He is also the one behind the recent stealing of the [[MechaMooks Sentinel]] fleet from a government base. When Gambit and Jean Grey go undercover to learn more about an unrelated GovernmentConspiracy, they are exposed but get an unexpected help from Onslaught. Later he tries to bring Jean over his side by showing her [[HotForStudent the dark long-repressed thoughts of her mentor Charles Xavier]]. She refuses. Juggernaut, who was [[TheWorfEffect attacked by Onslaught as well]], comes to the X-Mansion and asks Jean to look for its true identity [[MindReading inside his head]]. She does and finds out that Onslaught is none other than Professor X.

* ArcWelding: The opening of ''Onslaught: X-Men'' does this to the traitor tape that was a part of Bishop's backstory, revealing that Jean sent it after Onslaught attacked X-Men--and hence that the X-traitor was none other than Professor X himself, not that he was the first to die (while he didn't die, either, Jean believed it was Juggernaut).

* OnceMoreWithClarity: As noted under "Arc Welding", we're shown the X-tratior tape in its entirety as the official start of the crossover.

* WhamEpisode: Many of Marvel's major heroes are thought dead (actually sent to a pocket world), all remaining heroes have to pick up the slack (opening the door for the {{Thunderbolts}} development), the X-Men are blamed for the whole mess, and Hulk is split from Banner.

The heroes (and SelfDemonstrating/DoctorDoom) eventually manage to defeat him but in order to do that most of them have to enter his non-corporeal form, which the X-Men then have to destroy, making it look like they killed them. Professor X is imprisoned for Onslaught's crimes and the anti-mutant sentiments become stronger than ever.

It turns out that when Xavier brainwashed SelfDemonstrating/{Magneto}} several months before (to cause him to stop being a threat after he cruelly stripped the adamantium off SelfDemonstrating/{{Wolverine}}'s bones), a part of the latter's psyche merged with his own mind. Under the stress of constant failures and new misfortunes the Professor became more and more frustrated, until he developed a split personality, which eventually [[SplitPersonalityTakeover took a life of its own]] and was able to manifest in the corporeal world. Onslaught nearly kills the X-Men before leaving to capture [[ComicBook/FantasticFour Franklin Richards]] and ComicBook/XMan in order to suck out their powers and become [[PhysicalGod a living god]]. That brings him into conflict with both the Avengers, who were approached by X-Man, and Franklin's family, the Fantastic Four. Despite that Onslaught successfully kidnaps both of his targets, encircles Manhattan with Sentinels and prepares to TakeOverTheWorld.

It turns out that when Xavier brainwashed {{Magneto}} several months before (to cause him to stop being a threat after he cruelly stripped the adamantium off {{Wolverine}}'s bones), a part of the latter's psyche merged with his own mind. Under the stress of constant failures and new misfortunes the Professor became more and more frustrated, until he developed a split personality, which eventually [[SplitPersonalityTakeover took a life of its own]] and was able to manifest in the corporeal world. Onslaught nearly kills the X-Men before leaving to capture [[ComicBook/FantasticFour Franklin Richards]] and ComicBook/XMan in order to suck out their powers and become [[PhysicalGod a living god]]. That brings him into conflict with both the Avengers, who were approached by X-Man, and Franklin's family, the Fantastic Four. Despite that Onslaught successfully kidnaps both of his targets, encircles Manhattan with Sentinels and prepares to TakeOverTheWorld.

* ArcWelding: The opening of ''Onslaught: X-Men'' does this to the traitor tape that was a part of Bishop's backstory, revealing that Jean sent it after Onslaught attacked X-Men--and hence that the X-traitor was none other than Professor X himself, not that he was the first two die.

* ADarkerMe: What happens when the dark sides of Xavier and Magneto combine.
* AGodAmI: Onslaught at one point actually calls himself a god.

* WhatHappenedToTheMouse: In an issue of Spider-Man, Peter Parker and [[ScarletSpider Ben Reilly]] defeat a few Sentinels and run off at the end of the issue to help the other heroes fight Onslaught. They never show up in any of the battles with no explanation.

(Unknown to anyone, the heroes survived as they were recreated by Franklin's powers in another world, with no memory of their previous lives, as seen in the sequel "HeroesReborn".)

The heroes (and DoctorDoom) eventually manage to defeat him but in order to do that most of them have to enter his non-corporeal form, which the X-Men then have to destroy, making it look like they killed them. Professor X is imprisoned for Onslaught's crimes and the anti-mutant sentiments become stronger than ever.