Maybe this is offtopic but I really want the origin of the X gene explored.I start from cosmological backdrop let's say there is a primordial phoenix force that created life as a legacy the X gene is like a marker this force leaves on humans so that they could be receptive to commune with the phoenix force,the opposite of the phoenix force is the first fallen a force that seeks out only a select genetic makeup that lacks the mark to perpetuate a pure distinct race that is immune to phoenix influence.So both races have unique abilities, Apocalypse and Selene were selected by the phoenix as immortal guardians of humanity but Selene fell in love with a member of the first fallen and she had to consume a death seed to be able to be one with his kind.She was tricked into doing so ,so that she could siphon life out of people to make them receptive to the FF.While she lost her soul rendering her immortal.Her soul through a ritual was transferred into Apocalypse her co immortal.This did not make him mortal but necessitated and explained why he needed host bodies because his essence is double charged and so burnt through his own initial body and another's he inhibits unless through celestial technology.That would give a background to the two externals.Explaining why Apocalypse loaths weakness and love and is still tied to his mission that once the X gene is dominant to summon the phoenix he will be free of his immortal burden.While Selene seeks death as she serves a being of annihilation of all phoenix created creatures.Through time those manifesting X gene became many and wanted to live without being beholden to Selene's treachery or Apocalypse's vengeance. All that being said sure we can have X-Men without Magneto or Xavier,once you have the bigger picture, other titular mutant figures can be substitutes for them and the cause can be expanded for example one can say Elixir is a leader of a mutant faction who wants to activate the healing gene in humanity but cannot heal mutants and so this puzzles him and leads him to discover something unique about mutants and he finds out the lore and secrets behind the mutant phenomenon