Fox and Marvel should never pass up on an opportunity to introduce another great villain for future use in to the X-Men franchise and that's why X-Men: Apocalypse should be seen as the ideal chance to bring Mister Sinister in to the live action world. Apocalypse was key in Mister Sinister coming in to existence. In The Further Adventures of Cyclops and Phoenix, Apocalypse meets Nathaniel Essex, a British scientist in Victorian London, 1859. Through meeting Essex, Apocalypse learns the technical term for beings like him - mutants. Apocalypse persuades Essex and numerous members of the Hellfire Club (which already exists in Fox's X-Men universe) into working for him, intending to use them in his first major plan for world domination. He transforms Essex into Mister Sinister via his own advanced technology and demands that he creates a plague to ravage and transmute the global population, which causes Sinister to turn on him and create a plague that attacks only Apocalypse. This leads in to Apocalypse going in to hiding and hibernating, from which he is later awakened by his own followers to deal with Dracula, who, for the record, would be awesome in the X-Men universe.
