Oblivion is a cosmic entity in the Marvel universe who is in reality merely another part of Lady Death - however unlike her, he embodies non-existence rather than mortality and is dedicated to destroying all that exists.
Oblivion is a cosmic abstract entity and another aspect of Death, a personification of death. Oblivion represents non-existence and is a counter force to the expanding universe.
Oblivion came into existence together with the cosmic entities Eternity, Infinity and Death when the universe was created and these beings see each other as siblings. Another being, known as Galactus was born later, from the ashes of the previous universe and is also seen as a sibling by these beings. Oblivion has a very close relationship with Death and the two may be different aspects of the same being, just as Infinity and Eternity are. Just like Eternity and Death have a strong rivalry, Oblivion has a strong rivalry with Infinity, a rivalry usually fought through avatars.
Oblivion usually resides inside a pocket dimension, known as the Outer Void.
Oblivion has a daughter, the being known as Mirage, who assumed the human form of Marge Smith. As Marge Smith, Mirage tried to turn Robert Drake (Iceman), against her father. In return, Oblivion used three aliens known as White Light, the Idiot and Kali to attack his daughter. He also tried to turn Iceman against Mirage, but in the end Iceman convinced the two to settle their differences peacefully.
In his rivalry with Infinity, Oblivion empowered Maelstrom as his avatar and sent him his agent, Deathurge to assist him. As Oblivion's agent, Maelstrom tried to destroy the whole universe, but he was stopped by Quasar, the avatar of Infinity. Oblivion, Infinity, Death, and Eternity then came to a new agreement.
Maelstrom returned to life later and came into conflict with the Great Lakes Avengers. During this conflict, Deathurge was sent repeatedly to collect the souls of Great Lakes Avengers who died. When he tried to claim the soul of Squirrel Girl's sidekick Monkey Joe, Mr. Immortal used the opportunity to grab Deathurge, now just the size and shape of a squirrel, and defeat him. The recently deceased Doorman en
countered Oblivion, who made him his new agent, telling him that Deathurge had failed him. At Christmas, Deathurge tried to regain his position, but failed the test Oblivion gave him.
It is later expounded upon during a story involving the silver surfer and thor that oblivion is more than he first seemed. Oblivion explaines to the reader of the comic that the chaos king who recently tried to destroy everything was a part of his being and that he existed before and will exist after the universes have ended. He also implies that all of the chaos and destruction that occurs on every level of reality is at least partially influenced by him so that he may hasten the demise of reality and return existence to the quiet peace of nothingness.