A scientist from the planet of Colu, whose green-skinned humanoid inhabitants possess an intelligence far surpassing that of humans, Brainiac, or Vril Dox, abandoned his homeworld to explore the universe in search of infinite knowledge and, if knowledge is indeed power, infinite power. For decades, Brainiac had replicated the process of miniaturizing and bottling the greatest cities of every alien civilization he encountered, before destroying the planet that created them, all in the name of his mad hunger for omniscience. Among the worlds ended by Brainiac was Krypton, whose lunar colony Kandor was placed alongside at least two copycat cities in his collection. Meanwhile, Brainiac slowly recreated himself as a living computer, replacing much of his biological components with cybernetic equivalents. Years later, a swarm of nanobots was deployed on Brainiac's behalf to scout out the Earth in preparation for the real Brainiac's arrival. Taking control of the mind of a sideshow mentalist with real psychic powers named Milton Fine, this Brainiac drone was met with opposition from Superman. Other Brainiac drones, each initially believed to be the true Brainiac in some form, appeared on Earth in an antagonistic role to Superman and the Justice League of America, oftentimes in alliance with Lex Luthor. It was only recently that Superman and Supergirl encountered Brainiac's true form and stopped him from shrinking Metropolis and destroying the solar system by inducing the Sun to explode. Now a more dangerous foe than ever to the Man of Tomorrow and his allies, Brainiac desires the knowledge to unlock the secrets of the Multiverse, targeting Earth, the central point of each parallel universe, to acquire it.
- Brainiac is the primary antagonist responsible for the events leading up to the influx of Future Lex Luthor's exobytes upon the world's inhabitants.
- Catching the planet unaware, Brainiac manages to encase a large majority of Metropolis and Gotham City in energy fields in preparation for digitisation. Unable to stop him, the Justice League turns to the new exobyte-empowered heroes to turn the tide.
- In the Batcave Raids, Brainiac has located and infiltrated the Batcave in order to obtain Earth's knowledge through the Batcomputer. Players will fight Brainiac's Avatar of Tech, which is the embodiment of what he's learned of Earth's technology, before fighting a robotic drone of Brainiac himself. When defeated, Calculator and Oracle hack into Brainiac's systems and place him in a bottle.
- In the Fortress of Solitude Raids, Brainiac invades Superman's fortress in order to steal the kryptonian Sunstone Crystals hidden there. Superman and Luthor are forced to team up in order to prevent Brainiac from acquiring the crystals and players will have to eventually fight his Avatar of Meta, made from the sunstones.
- In the Themyscira Raid, Brainiac has taken a source of magic called the Flame of Change and has built an Avatar of Magic around it, using the Flame's power to strengthen his troops. Heroes and villains will travel to the island to aid Wonder Woman and Circe in defeating Brainiac's newest Avatar.
- In The Prime Battleground raid, heroes and villains will have their final confrontation with Brainiac as he unleashes his Prime Avatars onto the world.
- In the Return to the Nexus Operation Brainiac attempts a resurgence to retake the Nexus of Reality.
- Brainiac first appeared in Action Comics #242 (July 1958)
- Brainiac is voiced by Corey Burton, who had previously voiced the character in Superman: The Animated Series, Justice League, Justice League Unlimited, and Legion of Super Heroes.
- Brainiac boasts a 12th level intellect, whereas humans only possess a 6th level intellect.
- Vril Dox II; aka Brainiac 2, is the clone son of Brainiac. While as cold-hearted and manipulative as his "father", Brainiac 2 freed his home planet from the ruling dictators and became the founder and long-time leader of the interstellar police organization known as L.E.G.I.O.N., which was created following the destruction of the Green Lantern Corps by Parallax (Hal Jordan). Vril later has a son, named Lyrl Dox; aka Brainiac 3.
- Brainiac also has a descendent in the 30th and 31st centuries named Querl Dox; aka Brainiac 5, who worked with the Legion of Super Heroes to atone for his great-great-grandfather's misdeeds. Brainiac 5's ingenuity with technology led to the invention of, amongst other things, the Legion's flight rings and the force field belt which became his signature device in combat. He has also managed to designed various methods of time travel to enable the team to travel to the 20th and 21st centuries.
- Brainiac as he appears in DC Universe Online appears alongside other versions of the character in the comic book Convergence #0 (April, 2015).