Earth-4321

The Universe from Marvel: The End, in which the pharoah Akhenaten is conscripted by the Celestial Order. After several thousand years, he returns to Earth to become its absolute monarch (having slain almost all of the heroes). Thanos managed to reach the source of his (and the Order's) power, the Heart of the Universe.

He claimed the power for himself, retroactively writing the Order and Akhenaten out of history. However, he then learned that the Universe had a fatal flaw, which only grew worse as he tried to repair it. Bemoaning that the Creator had made him the butt of a cruel joke, Thanos ultimately sacrificed himself to set the Universe right. He made certain, however, that the history of the saved universe would have no hint of his sacrifice, so that one could ever credit the great nihilist for saving the entire universe.^[1]

In the distant future (some 300-400,000 years in the future), after humanity had wiped out and repopulated the planet^[2] Hydra of Earth-1720 used it as a base as there was no variant of any of them. The Exiles tracked them down to this reality and confronted them.^[3]