The Gambit Deluxe
Remy LeBeau is known for being the charming thief Gambit, who has the mutant ability to charge and explode inanimate items. Gambit was born into the Thieves Guild and went on to become a secret operative for the evil Mister Sinister. He was invited to the X-Men after befriending fellow mutant thief Storm, and given the chance to redeem himself.
Despite his moral disagreements with much of the X-behavior, Men's Gambit's fondness for lone children allowed him to fit in well with the team and form relationships with many of its members, particularly Rogue, with whom he established a romance.
The X-Men rejected his membership after the public revelation of his relationship with Sinister, though he later returned.