10 Marvel Supervillains Who Almost Destroyed The Avengers

Michael Korvac started life as a simple man working as a technician in Earth-691 alternate universe in 3007. When his version of Earth gets conquered by the alien Brotherhood of Badoon, Korvac sells out the human race in favor of saving his own skin, working alongside the aliens. He remains briefly in their good graces, until they find him asleep at his work post one day, the punishment for which in this culture is apparently being turned into a cyborg.

Thus, Korvac becomes a powerful cyborg, capable of absorbing any type of information or energy. Through a long series of events, he winds up traveling back in time to the present day, absorbing the Grandmaster's powers, and then ultimately absorbing Galactus' powers.

This lead to the Korvac Saga, a comic run in which the Avengers and the Guardians of the Galaxy teamed up in an attempt to stop this massively overpowered god-like villain. Their efforts all ultimately failed, as Korvac brutally slaughters wave after wave of heroes, with only a handful remaining alive. In a final confrontation with Thor, Iron Man, and Vision, Korvac commits suicide and restores the universe to its former state, bringing all of the characters back to life.