The colony of Titanian Eternals was founded about 750,000 years ago in the aftermath of a devastating civil war among the first generation of Earth's Eternals. The EternalsUranos and Kronos led opposing factions, which clashed in a conflict of ideals over the Eternals' destiny as a people. Kronos' side prevailed, and Uranos and his surviving followers were exiled into space and landed on the planet Uranus. There, they discovered a supply depot guarded by KreeSentry #213. When the Eternals destroyed the Sentry and raided the outpost, the Kree armada came to investigate, thinking Earth's solar system to be devoid of intelligent life. The armada destroyed the Eternals’ spacecraft, forcing them to crash on the moon Titan, where they hid from the Kree. There, the small group of survivors formed a colony beneath the surface of the moon, employing artificial life systems. These Eternals eventually fell prey to internal strife, and all of them but Sui-San were killed. Mentor, who had gone into voluntary exile, arrived on Titan, and the two Eternals began to repopulate the Titan colony. These new Titanian Eternals achieved much scientifically and socially, not the least of which was ISAAC, an immense computer system that could monitor and maintain all of the life support functions of the inner world. Under A'lars' leadership, Titan became a haven for peace. Then, A'lars sired the last two of his numerous children: Eros and Thanos. Thanos was born a mutant, and grew up with dark visions of conquest and destruction. Thanos left Titan, recruited an army of mercenaries, and returned to attack. Only a hundred of Titan's thousands of inhabitants survived, and Sui-San perished in the slaughter. Eventually, the Titanians rebuilt the colony and restored it to a place of meditation and the pursuit of knowledge.
Named inhabitants of Titan
Chaos - Cloned being created by ISAAC, while acting under Thanos’ control.
The Cotati - Refugees from Hala under the protection of the Priests of Pama.
Demeityr - Young Titan companion of Sundragon.
Dionysus - Cloned being created by ISAAC, while acting under Thanos’ control.
Moondragon - Adopted by Mentor and raised on Titan
Phyla-Vell - Cloned child of Mar-Vell and Elysius. Sister of Genis-Vell. Known as Captain Marvel, Quasar, and Martyr, the avatar of Oblivion. She's also the step-sister of Dorrek VIII.
Priests of Pama - Pacifistic Kree who protect the Cotati
Shastra -
Starfox - Hedonistic Avenger who is Thanos’ brother.
Stellarax - Cloned nihilistic terrorist created by ISAAC, while acting under Thanos’ control.
Sui-San - Mother of Starfox and Thanos. She was the last living follower of Uranos on Titan until she was vivisected by her son Thanos.
Sundragon - Cousin of Moondragon and companion of Demeityr.
Mar-Vell's grave and Genis-Vell's memorial monument are on the surface of the moon.
In other media
Television
In the Avengers Assemble episode "Thanos Rising," Falcon finds footage of Titan being firebombed while searching through Uatu the Watcher's computer.
Titan appears in the Guardians of the Galaxy episode "Titan Up." This is where Thanos trains his followers at and is where Sam Alexander's father Jesse is being held prisoner.
Film
Titan appears in '. In the film, Titan is a habitable exoplanet. The planet was left in ruin due to overpopulation which Thanos tried to prevent by offering a solution to his people which was exterminating half the population. Iron Man, Doctor Strange, Spider-Man, and the present Guardians of the Galaxy including Star-Lord, Drax, Mantis, and Nebula battle Thanos on Titan to protect the Eye of Agamotto, which contains the Time Stone. It is on Titan just prior to their battle when Strange used the Time Stone to go into the future and see millions of possible outcomes from their conflict with Thanos, but only one in which they win. As Iron Man is about to be killed by Thanos, Strange surrenders the Time Stone in exchange for Thanos sparing his life. Later, Thanos activates the Infinity Gauntlet after acquiring all six Infinity Stones and half of all life in the universe disintegrates. Iron Man and Nebula are the only ones on Titan who survive.
In ', Titan briefly appears when Doctor Strange opens a portal to Earth and allows him and the ressurected Star-Lord, Drax, Mantis and Spider-Man to join the Avengers in battle against Thanos and his army.