Origin:
* Fusion of Minds: Onslaught is born from the combined psychic energies of Professor Xavier, Magneto, and the mutant-hating villain, the Juggernaut (who was being controlled by Xavier at the time).
* Triggering Event: This fusion occurs during a climactic battle between Xavier and Magneto. Xavier, attempting to control Magneto, inadvertently draws in the Juggernaut's psychic energy, creating a powerful, unstable psychic entity.
* Transformation: Onslaught manifests as a physical being, possessing immense psychic power and a warped version of Xavier's ideals, twisted into a desire for complete control and domination.
Characteristics:
* Immense Power: Onslaught is one of the most powerful psychic entities in the Marvel Universe, capable of manipulating matter, reality warping, and controlling minds.
* Manipulative: He uses his power to manipulate events, control people, and create chaos.
* Ruthless: He has no qualms about destroying those who stand in his way.
* Driven by Control: He desires total control, believing himself to be the only one capable of bringing order to the world.
Notable Events:
* "Onslaught" Saga: The X-Men's major battle against Onslaught is a major storyline in Marvel Comics. The X-Men are severely weakened and defeated, and the world is left vulnerable.
* The Death of Franklin Richards: Franklin Richards, a powerful mutant child, is a key factor in Onslaught's defeat. Onslaught attempts to absorb Franklin's power, but Franklin uses his powers to create a reality in which Onslaught no longer exists.
* Return: Onslaught has returned in various forms, including as a mental entity residing within Xavier's mind.
Overall: Onslaught represents a profound exploration of the dangers of unchecked power and the struggle between order and chaos. He is a formidable adversary to the X-Men and a chilling reminder of the dark potential of psychic abilities.