The origin of Super Villians: Onslaught (Marvel Comics) - Onslaught (DC Comics) TWO-FER!!!

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https://en.wikipedia.org/wiki/Onslaught_(Marvel_Comics)

Onslaught is a fictional character appearing in American comic books published by Marvel Comics.

Onslaught was written as a sentient psionic entity created from the consciousness of two mutants: Professor Charles Xavier and Magneto. During a battle between the X-Men and Magneto's Acolytes, Professor Xavier used his telepathic powers to shut down Magneto's mind, rendering him catatonic. It was explained through the Onslaught crossover series that the darkest aspect of Magneto's mind escaped into Xavier's subconscious, where it "merged" with Xavier's own darker nature to eventually grow into a separate persona of its own.

Publication history
The character first appeared in cameo in X-Men: Prime #1 (July 1995), named in Uncanny X-Men #322 and made his first full appearance in X-Men vol. 2, #53 (June 1996) where he was co-created by writers Scott Lobdell, Mark Waid, and artist Andy Kubert.[1] He was written and introduced as a villain that was part of the effect of events in the 1993 "Fatal Attractions" storyline. Onslaught's introduction into X-Men storylines caused its own crossover event across multiple Marvel comic book titles (including X-Men and Uncanny X-Men issues, and Cable issues).

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https://en.wikipedia.org/wiki/Onslaught_(DC_Comics)

The Onslaught are a fictional team of state sponsored super powered Quraci terrorists published by DC Comics. They first appeared in Suicide Squad #1, and were created by John Ostrander and Luke McDonnell.

History
The Onslaught is a team of super-powered international terrorists-for-hire operating out of the outlaw nation of Qurac. The team was created and guided by Qurac's President Marlos and had accepted, as its first commission, the assignment of killing the President of the United States. Former Suicide Squad member Jess Bright, now a Soviet operative named Koshchei helped bio-engineer candidates for the team. At its inception, the Jihad was infiltrated by Nemesis and Nightshade, members of the advance team of the Suicide Squad, and was the target of a preemptive attack by the Squad (as seen in Suicide Squad #1 and #2).[1]

After their first clash with the Suicide Squad, Raza Kattuah now calling himself Rustam formed a second team based in an old World War II fortress called Jotunheim in southern Qurac. The name translates as "Land of the Giants", because the Germans believed only a race of giants could have built those mountains. Rustam used this team to terrorize civilians in New York City. Ravan, Ifrit and Agni were captured. Manticore and Jaculi were killed, but Rustam and Badb were able to escape. Ravan was eventually recruited by the Suicide Squad. Rick Flag carried out an unauthorized solo mission to Qurac which resulted in the destruction of Jotunheim, killing Rustam and countless Jihad members. The man known as Kobra would later kill Ravan while engaged in single combat.[1]

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