Eons ago, the Arcane constructed the highly advanced computer complex known as Dominus along with the first examples of the complicated "Ultra-Robots" that were until only recently needed to operate it. To conquer a planet, the Arcane would establish a secret base there and would eventually teleport Dominus and its robots to that base. Dominus would be modified each time so that it could affect the minds of the specific race inhabiting the planet to be conquered; in each case this modification process took a number of Earth years. Finally, when Dominus was ready, it would blanket the planet with rays that deadened the wills of the planet's natives so that they could easily be enslaved by the Arcane.

For years the Quist known on Earth as Lucifer successfully used Dominus to carry out conquests for the Arcane. Lucifer eventually undertook the conquest of Earth. Decades ago, he clashed with the superhuman mutant Charles Xavier, and years later engaged in conflict with Xavier and the team of mutants that Xavier had founded, the original X-Men.

Lucifer established a base hidden within a mesa in the Southwestern United States, to which Dominus was transported by the Arcane. Xavier and the five original X-Men tracked Lucifer to his hidden lair after Lucifer had launched a long-distance attack on Xavier. By the time they arrived there. Dominus had been fully modified to affect the minds of Earth people, and many "Ultra-Robots" needed to operate it had been teteported to Lucifer's headquarters. The robots were making the final preparations to begin using Dominus to project its will-deadening rays all over Earth. Xavier and his X-Men were captured, but the five young mutants escaped and succeeded in wrecking most of the robots. As a result, Dominus could not be operated. and the Arcane's attempted conquest of Earth was thwarted. The ruler of the Arcane, known as the Supreme One, teleported Dominus back to their home planet. Quistalium, and exiled Lucifer to the so-called "Nameless Dimension." Lucifer subsequently clashed with other Earth champions, and the rulers of the Arcane, deciding that Lucifer was thereby attracting too much attention to their race, allegedly had Lucifer "terminated."

The Arcane made further improvements on Dominus so that it could operate without the Ultra-Robots. However, in this redesigning Dominus, the Arcane made Dominus so powerful that it became the master of the Arcane themselves. The sentient Dominus returned to Earth, establishing a secret base within a mountain in Arizona, and preparing to conquer the planet.

When the West Coast Avengers arrived in the area, searching for Bonita Juarez once known as Firebird and now known as Esperita, Dominus sent its Earth minions to fight them. These minions were the human Sunstroke and three creatures created by Dominus through advanced technology: Butte, Cactus, and Gila. The West Coast Avengers defeated Dominus's minions but were then confronted by a Quist whose mind was controlled by Dominus, and through whom Dominus spoke. (The West Coast Avengers assumed that the alien humanoid they saw was the real Dominus.) Dominus manipulated the West Coast Avengers into standing on a platform that was actually the time machine invented by Doctor Doom, which Dominus had located. Dominus used the machine to send the West Coast Avengers back in time to the Nineteenth Century. Because the time machine was damaged, the West Coast Avengers would be unable to return to their own time using it: the time machine could now only travel into the past, not into the future.

Nevertheless, the West Coast Avengers succeeded in returning to their own time and tracked down Dominus to its lair. Dominus sent Sunstroke and numerous duplicates of Butte, Cactus, and Gila to battle the West Coast Avengers, but the West Coast Avengers defeated them all. But Dominus, revealing itself to be a machine, used its rays to deaden the wills of the West Coast Avengers. However, the West Coast Avengers' ally Moon Knight was not stopped by the rays due to his own multiple personality, each dose of Dominus's will-deadening rays only affected one of Moon Knights personalities. Unable to comprehend Moon Knights seeming immunity to the rays, Dominus went mad. The central core of the Dominus complex fled, launching itself into outer space.

Presumably, since it takes years for Dominus to undergo modification, Dominus will not return to Earth in the immediate future.

First Appearance: X-MEN # 21