The undead Hyperion became the defacto leader of the evil Squadron Supreme and was romantically involved with the woman who was altered to be Power Princess (much like how the real Hyperion and Power Princess share a relationship).
When the Guardsman Alpha Team were sent to investigate he was weakened by some Argonite stored in Project PEGASUS. Fearing the possibility of more Argonite, Hyperion was forced to leave the Squadron Supreme behind and travel into the Earth's core and thus escape Project PEGASUS.
While rampaging across Kansas, devouring most of the population, he was confronted by Kansas' superhero team The Harvesters. Dispatching of most of the team with relative ease, Hyperion collapsed from Mad Cow Disease he had received from eating tainted cows. Whether Hyperion survived this affliction or not wasn't revealed.