Fall-Out
Stryfe and Apocalypse were both supposed to have remained dead after the story but both would be brought back to life. Excluding the Age of Apocalypse storyline, Apocalypse would return in Cable #19. Stryfe meanwhile would return as a ghost who possessed Cable. The story ended with Cable freeing himself from Stryfe's control, sending Stryfe's spirit to Hell for all eternity. Stryfe reappeared when his ghost attempted to escape Hell by possessing X-Force member Warpath but was foiled by the members of X-Force.
Ultimately Stryfe would be brought back to life as a time anomaly, having shown up out of the blue alongside the Dark Riders during a crossover between Cable and X-Man and would go on to bedevil the X-Men until his most recent death during the Gambit/Bishop mini-series. Stryfe would yet again return after M-Day and seemed to perish again, although it is unknown if it is a Stryfe from another reality.
The major long-term result of X-Cutioner's Song was the Legacy Virus. Stryfe had earlier given Mister Sinister a canister that he claimed contained two thousand years worth of genetic material from the Summers bloodline. When Sinister opened it after Stryfe was apparently killed by Cable, he found nothing inside. Far worse than that, the canister actually contained a plague, Stryfe's "Legacy" to the world. The virus, presumably from the future, was 100% fatal and struck only mutants but later infected the human doctor and long-time X-Men ally, Moira MacTaggert. MacTaggert would ultimately develop a cure just before her death, though it would cost the mutant Peter Rasputin (Colossus) his life, due to the cure requiring a mutant to die in order to activate it.
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