His name is Legion, for he is many. A fragmented, multi-personalities individual, he is clinically insane and dangerous to all those around him. His personalities have fragmented into three distinct personalities, that of himself, Ian, and Lucas.

David is the son of Charles Xavier, who until recently had been unaware of his existence. His mother is Gabrielle Haller, who divorced Xavier shortly before David was born. She kept the knowledge of David's existence from Charles, mostly because she didn't want to complicate their simple lives. Gabrielle and Charles did not part on the best of terms, and David (and Lucas) bear a great grudge against the father they never knew. David is a teenage boy who speaks with an American accent. He never openly used any powers as himself.

Ian is the most docile of the three, being mute and generally doing little. He appears to be a boy of about 9 and his loyalty goes with Lucas. His powers focus mainly on the pyrotechnic abilities.

Lucas looks to be a Scottish male in his early to mid twenties. He is the most dangerous. Completely greedy, scheming and power mad, Lucas seems to be in control of the more considerable powers at David's disposal. His telepathy and telekinesis are much stronger than anything the X-Men have dealt with to date.

Lucas conspired, using Ian as his accomplice and David as his pawn, to have his father meld them into one. He wanted to be free of their unpredictable changes from one personality to another and knew that Xavier was the only person powerful enough to rid him of the others. After Xavier's failed attempt to help David, Lucas gained control of their body and was last seen flying off into the horizon. But it is very likely he will be back, sooner or later.