Mesmero

Mesmero was a member of the Bayville's circus called the Circus of Mystery. To be able to unlock Apocalypse's gateways, he used his mind controlling abilities to control Jean, Nightcrawler, Spyke, and Kitty Pryde to steal three Tibetan rings from the Han Dynasty. These rings have unlocked Apocalypse's first passageway.

Mesmero then used Gambit to steal a half spider stone from Angel. Magneto then chased him in London to prevent the half stone to be ignited to its other half but the two halves were united forming a gigantic green spider, Magneto was able to destroy the spider. He then discovered that the spider was a guardian of the second gateway and with it destroyed, the secong pasageway was opened.

Mesmero then asked help from Mystique and controlled Rogue to absorb the powers of her co-X-Men members, the Brotherhood and the Acolytes. It caused panic to other people to that place. By using the powers that Rogue have absorbed, she awakened Apocalypse. It then opened the third passageway. When Apocalypse was awakened, he lost interest to his loyal servant. He was then found in his carnival and were tortured by the X-Men to know Apocalypse's plans with Professor X reading his mind.

Mesmero was Apocalypse’s servant, who made it his mission in life to resurrect his master, no matter what or who he had to go through to get it. Possessing the power to make others do whatever he wished, Mesmero entered the minds of several X-Men and used them to steal rings that were part of a key to free Apocalypse.

He later used Gambit in order to steal an ancient artefact from Warren Worthington, and irked the ire of Magneto by using his henchmen. When Worthington went to Xavier after the spider stone was stolen, Mesmero now had both The X-Men and Magneto’s Acolytes doing their all to prevent him from resurrecting Apocalypse. He later used Rogue and Mystique to do his bidding for him and finally freed his master.

Apocalypse then completely abandoned him, and when he finally did make his move, Mesmero revealed his plan to The X-Men after a little help from Wolverine.

History
At first, Mesmero was a small crook. He would go to society parties and use his powers to make guests to give him all of their possesions and forget about them. Magneto found Mesmero and wanted him to make Polaris believe that she was the daughter of Magneto. Mesmero succeeded, but it was revealed by a Sentinel the Magneto that gave the orders to Mesmero was actually a robot. Mesmero attacked and hyponized the X-Men into believing that they were Circus performers. Beast freed the X-Men and stopped Mesmero. Mesmero then was rendered unconsious by Magneto. He was then stranded in South America.

Mesmero later went to England to make money legally as a Hypnotist. The Fenris twins found him and forced him to work for them. Mesmero hypnotised Excalibur into protecting him from Fenris. Shadowcat broke free of Mesmero's control over the team, and Excalibur defeated Fenris. Mesmero then traveled to New York City and he tried to hypnotise the city to do his bidding. He was stopped by Spider-Man. One time he tricked Dark Riders into thinking they threw him off a cliff. At one point he was captured an sent to a special prison. He hypnotised his way out, but Sentinels were sent after him. He panicked and took hostages. Alpha Flight came and defeated both the Sentinels and Mesmero.

He later joined Weapon X because he was promised that his powers would be increased. After he agreed his powers were increased so much that he could hypnotise a whole crowd just by glancing at the crowd. Mesmero visited his dying mother, he hypnotised doctors to do as much as they could but she still was not going to live. He then hypnotised his mother into believing she was as healthy as she would ever be. Right before she died, she told her son that she knew that she had been hypnotised. Mesmero lost confidence in himself and he lost his powers. Agent Brent Jackson then spent much time helping Mesmero gain his confidence back. Eventually he regained his confidense and his powers. Then M-Day came and he lost his powers for good. He was now forced into poverty.

When all hope was lost, he gained a relationship with a woman who saved his life. Sombody loved him, something that never happened without the help of his powers. He put his past behind him and he began living his life as Vincent.

Power
Mesmero was the most powerful hypnotic on the planet, but is depowered after M-Day.