Legion's origins are unrevealed. He may be, like other members of the Special Executive, a Gallifreyan mutate, spawned in the Looms of Rassilon, or he may be a creation of the Gallifreyans. The leader of the Special Executive, "The Steward", sought to bring Fascination into his group, despite the fact that Cobweb predicted that it would not occur for another 300 years. Thug accompanied them on this adventure and was reunited Legion, whom he embraced as a friend or relative. Braddock went berserk upon awakening in the Dimensional Development Court. Legion was one of the SE who tried, and failed, to subdue Braddock. After punching one of Legion's counterparts and seeing them all develop nosebleeds, Captain Britain said, "Let's see what happens when I break one of your backs!" Legion was not in favor of the idea. He was also present at the trial of Saturnyne, in which Mandragon obliterated the entire dimension of Earth-238 from existence. This not only killed trillions of trillions, but also wiped out any evidence of Saturnyne's innocence. Saturnyne was sentenced to death, and Braddock went berserk, battling the security forces of the DDC. At Wardog's direction, Legion leapt to Braddock's side. Legion and the rest of the SE continued the struggle until Wardog led them to teleport to Earth-616 to escape. They took up temporary residence in Braddock manor. The events on Earth-616 began to parallel those of Earth-238, the Crooked World. Mad Jim Jaspers power and influence began to affect reality, and the deadly Fury closed in on Captains Britain and UK. Meanwhile, Legion played himself in chess, which ended in stalemate after stalemate. Cobweb was most annoyed. Legion and the SE joined the battle against the Fury. Correctly fearing the deadly power of the Fury, Oxo instructed Legion to back off and lose himself in the crowd. Legion responded, "But I am the crowd," as the Fury slew one of his counterparts. Legion and the others realized that he would only have days to weeks until his timeline caught up with that of his deceased future counterpart. Legion sat in shock over the body of his future counterpart during the struggle with the Fury. Zeitgeist figured that he had three months at most "before he snuffs out forever." After the conclusion of the battle, Legion left with the rest of the SE. Cobweb saw the future image of herself scattering Legion's ashes.

Powers: Legion can double back on his own timeline, thereby summoning countless future counterparts, each separated by a split second. As such, Legion can form ten to twelve seeming duplicates of himself to accomplish multiple tasks at once, or to increase their fighting power. Legion is powerfully muscled and is usually engaged in hand-to-hand combat, possibly superhuman, strength and excellent fighting skills