|Powers and Abilities||Mind Control|
He used his mind-controlling powers to unlock the gates that had sealed the ancient mutant Apocalypse away and arrange for his return.
He was a part of a carnival that visited Bayville, called the Circus of Mystery. He used Jean Grey, Nightcrawler, Spyke, and Shadowcat to steal three Tibetan rings from the early Han Dynasty. He successfully obtained the rings and unlocks the first of three gateways.
Mesmero then used Gambit, one of Magneto's Acolytes, to steal half of a spider stone from the home of Angel. Furious, Magneto chased Mesmero to London, hoping to prevent him from acquiring the other half of the stone, but nevertheless the two halves are combined and the stone transforms into a giant green spider. Magneto destroyed the spider only to learn that the spider was a guardian. Destroying it was just what Mesmero had wanted, opening the second gate to free his master.
To open the third and final gate, Mesmero enlisted the help of Mystique, over whom his powers had no control. He controlled her foster daughter, Rogue, and forced her to absorb the powers of all of her fellow X-Men, as well as members of the Brotherhood of Mutants and the Acolytes. Mesmero deceived Mystique into opening the third gate, then forced Rogue to awaken Apocalypse by "feeding" him the powers she had stolen earlier.
However, once Apocalypse was reawakened, he lost interest in his former loyal servant, and the X-Men found Mesmero some time later, back in his tent at the carnival. Charles Xavier was able to learn Apocalypse's plan by scanning Mesmero's mind.
It is unknown what happened to Mesmero afterwards.
Powers and Abilities
Mesmero was voiced by Ron Halder.
Mesmero fills the role taken by Mister Sinister in the comics as the assistant to Apocalypse. In X-Men, that role was initially filled by Mystique. The only time Mister Sinister has been the assistant to Apocalypse is in Wolverine and the X-Men.
In the Comics
His real name is Vincent and his last name is unknown.
He was an assistant to Magneto.