Mr SinisterI shan't say too much about him, as he's a pretty big villain in the Marvel Universe and other's may want to use him or implement him into their own backgrounds. Quite simply, Gambit hasn't paid his debt fully, and Mr. Sinister isn't pleased with that. If he and Gambit were to meet again, it would prove destructive for all in the area, to say the least.
Bella Donna BoudreauxHead of the Assassin's Guild in New Orleans; childhood friend of Gambit's, and also his Ex-wife. Following her brother's death at the hands of Gambit, and his refusal to take her with him in his exile, Bella Donna took up the mantel of leader for her Guild. Over the years, she tried several times to get Gambit back to New Orleans and to her, as she still loved him. Recently, she has gone missing, and is presumed dead - now, a fight for power in New Orleans has begun.
Julien BoudreauxBella Donna's older brother. Following the marriage of Gambit and his sister, the union that was to bring peace between the guild's, he refused to let it happen. Challenging his brother-in-law to a duel, the two battled, Gambit winning and accidentally killing Julien as his mutant powers manifested, turning a simple knife thrown at Julien into a kinetically-charged bomb. Gambit was exiled; Julien, presumed dead. However, rumours have spread of his apparent resurrection. Some people believe he never really died, instead faking his death to have Gambit exiled, and then hiding for several years as a soldier in Vietnam. Whatever the cause, the assassin is back, wanting to re-take control, and exact revenge on Gambit.
The Marauders The super-powered mercenary group created by Mr. Sinister and Gambit's ex-affiliates. After having left the group both injured and disgusted by their actions, animosity remains between the members and Gambit. Notable members include Sabretooth, Vertigo, Prism, Malice, and Riptide, among others.