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. 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, including Colossus's sister, Illyana Rasputin, causing Colossus to leave the X-Men. It 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.