Originally Posted by
Sutekh
1) Mutants have recently spent time in Limbo/Hell, so some sort of mystical threat or taint or demonic affliction / uprising tied to those mutants could be the next 'everybody vs. X' event. If the various mutants have become or are being used as 'weak points' and demonic events are occurring because of their presence in an area (including fun stuff like random portals to Hell opening up, or mutants being possessed), the supernatural community, led by Dr. Strange, Voodoo, Shaman, Scarlet Witch, etc. could be the forces aligning against them, along with various other heroes.
2) Someone's been messing with time, again, and future and / or past versions of characters are appearing and disappearing. Some sort of 'time-keepers' are trying to prevent an Incursion-level time-quake by getting rid of all the time-displaced mutants, including Cable, Bishop, Rachel Summers, the O5 X-teens, etc. as well as time-manipulating or meddling X-peeps, like Beast, Tempus, Kiden Nixon, Legion, Ilyanna, Timeslip, Lacuna, etc. etc. Members of the superhero community getting involved could include people with time machines or 'cosmic consciousness,' ranging from Infamous Doom to Reed Richards to Quasar to a reborn Genis-Vell (who, last seen, was scattered across time).
3) The High Evolutionary. He's already tried to wipe out mutants at least twice. His new idea will be to relocate them all to Counter-Earth (at first, voluntarily, then by force, perhaps unleashing a 'mutant cure virus' that will depower anyone who tries to stay), and, for a year or so, X-stories will be utterly divorced from Avengers/Champions/etc. continuity, as they are on different Earths. But Counter-Earth is unstable, and if it explodes, mutantkind could go down with the ship!
4) X vs. X! The top 1% winners of the genetic lottery versus everyone else! Forge goes mental and designs a satellite-based version of his No More Mutants gun (first used on Storm), and starts randomly zapping whole sections of the planet with his 'Mutant Cure,' all because Storm broke up with him, and he thinks mutants suck. Mutants who hate being mutants, because they are ugly freaks with little or no powers, persecuted for the awesome 'power' of leaving a trail of paralyzing mucus behind them, or smelling like a dead skunk, or having radioactive tentacles where your genitals should be, will be eager to bathe in the rays of his Satellite of Self-Loathing, while the cool mutants who look like underwear models, live in a mansion and have amazing superhero powers will be all 'How can you betray your heritage, sewer-dwelling rat-eating race-traitors?'