5. Madelyne Pryor
Marvel ComicsMadelyne Pryor is a clone of existing X-Men movie character Jean Grey and, now that Jean Grey has been confirmed as alive in the timeline (see the end of Days of Future Past for details), she would be a very personal antagonist to the character and would make for a fantastic on-screen rivalry that could bring Grey back to prominence in the franchise. Pryor was created by the evil Mister Sinister (we'll get to him later) with the aim being to have her reproduce with Scott Summers (Cyclops) to create an incredibly powerful child that Sinister could manipulate for his own means. Being a clone of Jean Grey, Pryor possesses the same powers as the powerful mutant. These include telekinesis, telepathy and teleportation and, being a Jean Grey-level character, she is a major threat to the X-Men. Pryor's development would see her become the Goblin Queen - having been influenced by the evil, magical demon Sym - which resulted in her powers being magically enhanced and also gave her various magical abilities of her own (such as the ability to warp reality itself). Having Pryor in the X-Men movie universe would make for an emotional and intriguing storyline - and her introduction could also be a way to introduce magic to the franchise (and the fact that a hot redhead would have to play her would do the character's popularity no harm either).