Mr. Sinister's big screen debut is long overdue, and while he's a relatively newer addition to the X-Men's rogues gallery (he first appeared in 1987), the impact he's had on their lives has been massive. A geneticist fascinated with experimenting on mutants, Nathaniel Essex has been around since Victorian times, and has a twisted fascination with the Summers and Grey bloodlines, often trying to play God with their lives. One of Mr. Sinister's most despicable acts came before he was actually introduced though, and that was during the now iconic "Mutant Massacre" storyline. Deploying his Marauders to the underground home of the Morlocks (mutants with visible deformities who hid there because they were unable to hide in plain sight among humans), he ordered them to wipe them all out, and it instantly became clear just how twisted he is.
