Abyss was a mutant, alias Nils Styger, with the ability to absorb things into a pocket dimension contained within his body. A mutate from Genosha, Abyss contracted the Legacy Virus, and served as lab assistant and bodyguard to Dr. Renee Majcoomb, a scientist. He was later cured with the rest of mutantkind, but wound up a sort-of prisoner of the X-Corps. Alongside the X-Corps, he defeated Mystique by absorbing her. Most recently, he was summoned by the demon Azazel, who sought teleporting mutants' aid to invade Earth. Abyss expelled Mystique when he tried to use his powers in Azazel's dimension, and was used by Polaris to destroy the demon's castle. Abyss is on his own once more.