When Mary Purcell was young her mutant power caused an explosion which killed her.
Mary Purcell bonded to Remy LeBeau so he would survive the time he spent in Antarctica. She believed she and Gambit were soul mates and became very jealous of him. She kept his from spending time with Rogue and warned him not to tell anyone about her presence.
She kidnapped Remy when she was discovered and took him to her home and told him what had happened to her. She tried to bond with him completely to make a new being of pure energy, but she was stopped by Rogue. Remy, who detonated the containment device that held her. It is possible that he killed her when this happened.