1960s
Ego once told Thor that his existence was the result of a scientist merging with a planet when that planet's sun went nova.[10]
Inside the Black Galaxy, Ego's ambitions turn towards conquest. He starts absorbing space vessels and other planets to gather strength. This behavior attracted the attention of the Rigellian Colonizers, who feared that the nearby Ego would consume their homeworld. They asked the help of the thunder god Thor, to defeat Ego. Accompanied by a Rigellian Recorder, Thor encountered Ego, who forced him into his body and created Anti-body minions to attack him, intending to test their strength and planning to send them across the universe to conquer other worlds. Thor fought them off and stunned Ego with a powerful storm. Feeling humiliated by his defeat, Ego vowed never to leave the Black Galaxy.[11] Several months later, a weakened Galactus invaded Ego's space and sought to replenish his energy by consuming Ego. Thor aided Ego in battling Galactus and drove Galactus off.[12] In gratitude, Ego takes in the Wanderers, a group of various alien races whose planets had been the first to be devoured by Galactus billions of years ago.[13]
1970s
The Rigellian Tana Nile took a sample of Ego to fertilize sterile worlds being considered for habitation.[14] However, this drives Ego insane, and it soon gives in to its primordial urges and absorbs the Wanderers, which causes Thor to side with a returning Galactus. Assisted by Hercules and Firelord, Thor holds Ego off until Galactus attaches a massive starship engine to Ego's south pole, which drives him constantly through space and prevents him from being a threat to other planets and populated sections of the universe.[15]
1980s
Years later, Ego gains control of the engine and tracks Galactus to Earth, seeking vengeance. Unable to locate him, Ego attacks Earth. He causes massive destruction, which is later undone by a reality-altering mutant. The Fantastic Four attempted to defeat Ego by removing the power cell from one of the attached propulsion engines, which the Thing attempts to throw into Ego's "brain". In response, an angered Ego attempts to counter with his remaining engines but is propelled into the Sun.[16]
Ego, however, slowly reforms from a few surviving particles and repairs the propulsion unit.[12] Ego then digests a number of Dire Wraiths, to replenish its energy reserves, and battles the Space Knight Rom.[17]
Ego later joins the Elders of the Universe in a plan to destroy Galactus. Ego is sidelined before the confrontation when he is defeated by the
1990s
Ego attacks a Korbinite fleet and fights the hero Beta Ray Bill. Ego reveals to Bill that Galactus's propulsion unit is driving Ego mad, and the fleet subsequently destroys the propulsion unit.[20] A sentient bio-verse, initially described as "Super-Ego", then begins to consume Ego, but Ego eventually escapes.[21]
2000s
Driven mad by the Supreme Intelligence, Ego lashes out at other planets, destroying them while trying to 'awaken' others like itself, until it is defeated in a battle with Professor X, the Silver Surfer and Cadre K.[22] Ego is subsequently captured and sent to Earth as an "infant" in spore form.[23] As Ego grows, it begins to consume the Earth, with the Supreme Intelligence intending to allow it to grow so that the Kree can take control of Ego and use it as a weapon against the rest of the universe. Quasar absorbs it to prevent this.[24]
When Quasar dies during the Annihilation war,[25] Ego was released back into the Universe, only to be approached by the Worldmind to join the new Nova Corps.[26]
2010s
Ego learns he was one of two entities created by the Stranger for a science experiment, and that his brother Alter-Ego has been held in captivity by the Collector since birth.[12] While Ego seeks a similar entity to itself, the Stranger has arranged for Alter-Ego to hate Ego, intending to learn through their battle if freedom or captivity breeds a stronger will. Alter-Ego is wounded and loses mass when Ego is forced to attack it in self-defense, but Thor intervenes before Ego can strike a killing blow. The fragments of Alter-Ego form into a moon of Ego, and the two begin to travel together as a family.[12][29]
When Ego is infested by large insect-like creatures he hires Rocket Raccoon to eradicate them.[30]
Galactus, changed into the Life-Bringer by the Ultimates, encounters Ego after regaining his strength after a battle with the new universal construct Lagos. Ego attacks Galactus as he journeys to his inner brain at the center of the planet, however loses control of his constructs, which realize that Galactus is not a threat.
2020s
Ego later allows a Skrull cult called the Brethren of the Forgotten Flame to take shelter in its surface.[34] However, the Guardians of the Galaxy discover that the cult is committing a mass sacrifice, encasing Ego in a dark shell. After breaking free of the shell, Ego is possessed by the cult's object of worship, Dormammu.[35]
