The Dominators are a race of bipedal extra-terrestrial creatures existing on Earth-1 in the Arrow-verse (another version exists on Earth-38). They serve as the main antagonists of the 2016 Arrow-verse film Heroes V Aliens!".
The Dominators are fearsome aliens with advanced technology who venture across the universe, looking for potential threats. They speak in an alien language but can communicate with other species through their telepathic powers.
In 1951 on Earth-1, the Dominators learned of the Earth-born meta-humans, the Justice Society of America. They perceived them to be a potential threat, and so, in the town of Redmond, Oregon, a Dominator ship hovered over a track of uninhabited land, idly. Human military troops arrived, but the Dominators subsequently attack them, killing some and taking a few to be probed for information. A truce was maintained between the Earth's leaders and the Dominators afterward, and they left Earth behind.
65 years later, in late 2016, the Dominators became aware of the meta-human population created by Eobard Thawne's particle accelerator accident, causing some of Central City's citizens becoming meta-humans, including Barry Allen/The Flash, who, in early 2016, used his time-traveling powers to save his mother Nora Allen, creating the "Flashpoint" timeline. After he fixed his mistake and restored the timeline, the Dominators came to Earth to find him, fearing that he would use his powers to once again tear apart the space-time continuum.
A Dominator dropship crashed outside Central City, which Barry found. Dominator soldiers poured out of it, allowing them to enact their plans. The next day, Barry brought A.R.G.U.S. leader Lyla Diggle to S.T.A.R. Labs, where she informed Team Flash of the Dominator threat and their attack in 1951. She also got them to listen to a Dominator message intercepted recently, in which they warn people that any action against them as done in the past will be met with punishment. To face their new foes, Team Flash reaches out, contacting Team Arrow in Star City and the Legends team. Barry and Cisco Ramon/Vibe bring Supergirl of Earth-38 over to Earth-1 as well, where she tells them that Dominators from Earth-38 attacked her home-planet Krypton before she was born, taking people and leaving, just like in Redmond. While they prepare to face their foes, the Dominators are shown at a warehouse in Central City with a mind-control device, as one of them makes contact with another Dominator on their mothership, who tells them to bring the human leader, whom they perceived to be the President of the United States. The next day, a Dominator ship flies by an airport and kidnaps him, then returns to the warehouse.
A portion of the heroes go to the warehouse that night, including Supergirl, where they find the President tied-up and needing help. A Dominator appears overhead and speaks to them telepathically, then uses a laser weapon to disintegrate the President. Realizing that this is a trap, the heroes try to attack, but the Dominator activates the mind-control device, and thus they return to S.T.A.R. Labs to attack their comrades. However, Oliver Queen/Green Arrow and Wally West, who recently acquired super-speed, manage to fight them off. Barry lures Supergirl to the warehouse and tricks her into destroying the mind-control machine, freeing them. Just as they return to S.T.A.R. Labs to wrap things up, Ray Palmer/Atom, Thea Queen/Speedy, Sara Lance/White Canary, John Diggle/Spartan and Oliver all disappear in a stream of orange light, having been teleported away.
Oliver, Ray, Sara, Diggle, and Thea find themselves in a parallel reality in which Oliver, Robert, and Sara never boarded the Queen's Gambit and never became the Green Arrow. This "shared hallucination" was created by machines on the Dominator mothership that kept them in an unconscious state, similar to sleep, in order to probe their minds and gain information on Earth's meta-human populace and military weaknesses. Meanwhile on Earth, Team Arrow's remainder (Curtis Holt/Mr. Terrific, Felicity Smoak, Rene Ramirez/Wild Dog and Rory Regan/Ragman) worked with Cisco to hack a Dominator communication device, hoping to learn the aliens' language and find their friends. Curtis used a "3PO processor" on the device, but this caused it to explode due to interaction with foreign technology. To get more headway, they track down Laura Washington/Cyberwoman, who stole technology from NASA and used it to make herself a dangerous cyborg with laser weaponry.
In the hallucination, Oliver is engaged to Laurel Lance (Black Canary before her death), Ray is engaged to Felicity, Diggle is the Green Arrow in Oliver's place, and Sara and Thea are intended to be bridesmaids for Oliver and Laurel. However, Oliver and Diggle eventually notice the Smoak Technologies building in the city, and the fake Felicity's claim that she never owned a company leads them to feel confused. Diggle, remembering fragments of the real-world just like Oliver, manages to draw a crude Dominator face (resembling their comic-book incarnation). Now aware of where they are, they realize that the Dominators will do anything to stop them from escaping; suddenly, an incarnation of Oliver's previous nemesis Deathstroke appears, but Sara kills him with his own sword. Sara manages to make Ray remember the real-world later. In the real-world, Team Arrow, Barry and Supergirl go to Cyberwoman's last-known location and defeat her, removing a device on her arm. They use it to translate a Dominator transmission, which apparently has similarities to an ancient Hebrew dialect, and after finding the heroes' location to be in negative coordinates, they realize where they are; on the Dominator mothership.
In the hallucination, Thea remembers the real-world but wants to stay behind. The others realize that the Smoak Technologies building must be the way out, but appearing before them to stop them are many of the villains they have faced over the years; Deathstroke, Damien Darhk, Malcolm Merlyn, a member of Darkh's "Ghosts" group (likely Andy Diggle, John's brother) and a Deathstroke goon (presumably the same one that killed Ray's fiance Anna in the real-world). Thea jumps in to fight, with the resulting battle being won by the heroes. After Oliver tells the fake Laurel why he has to leave, they head to the Smoak Technologies building, where they find a portal back to the real world. After going through it, they wake up on the Dominator mothership and sneak around to elude their alien captors. Along the way, Ray memorizes a phrase used by a passing Dominator. After escaping on a Dominator dropship, they are promptly-pursued by more dropships, who fired a barrage of lasers at them. The Waverider, the Legends' timeship, arrives and saves them, having been told by Team Arrow where to find them. They realize that none of them being meta-humans is why they were taken; meta-humans could fight back against the aliens, but they were just normal people. Ray repeats the Dominator phrase from before, which AI Gideon translates as "We are nearing completion of the weapon", and also tells them that the mothership is heading for Earth.
DC's Legends of Tomorrow
As the mothership approaches Earth, the heroes return and realize that they can learn the Dominators' motives by meeting one in person that won't attack them. Promptly, Cisco, Felicity, Amaya Jiwe/Vixen, Mick Rory and Nate Heywood/Commander Steel use the Waverider to go to Redmond, Oregon in 1951, when the Dominators first arrived. Nate, Mick and Amaya exit the ship and leave Cisco and Felicity on-board and see the Dominators dragging human soldiers underneath their ship to be teleported up into the ship for probing. They run onto the scene after all but one of the Dominators are teleported onto the ship and Mick uses his flamethrower to leave him incapacitated. Suddenly, NSA agents arrive led by Agent "Glasses" Smith, who knock out the time-travelers and take them to a nearby lab for experimentation, bringing the Dominator along too. They wake up in a room with the Dominator and try to talk to him, but the NSA take him away for experimentation. In a lab room, Agent Smith and a scientist inject the Dominator with unknown drugs when the heroes are freed by Felicity and Cisco, who left the Waverider to save them. Realizing that they can prove the Dominators wrong about humanity being monsters, they save the captive Dominator and rebuild the dropship that Oliver and his friends used to escape the mothership in 2016. The Dominator uses the dropship to return to his brethren, leaving behind a communication device for Cisco.
In the present, Oliver, Barry, Sara, and Ray arrange to have the new President meet them to explain what they know, but an elderly Agent Smith arrives instead with an NSA crew to kidnap them. After defeating them, they get Smith to explain that the Dominators came because of Barry's reckless creation of "Flashpoint", which put the timeline at risk of destruction. He says that he's worked out a deal with the aliens; if Barry surrenders himself to the Dominators, they will leave Earth alone. If he refuses to comply, they will drop a "meta-bomb" on Central City, wiping out the entire city's meta-human population. On the Waverider, back from 1951, Cisco uses the communication device to listen to a hologram of the Dominator they saved before. The Dominator explains that they'll take Barry, but kill all meta-humans if he doesn't listen, just as Smith says. Cisco assumed that saving him before would change the Dominators' view on humanity, but he was shocked to learn that it doesn't matter at all.
Dominator ships appear across the world, the one carrying the "meta-bomb" hovering over Central City due to its heavy meta-human populace. The heroes then gather up on a building rooftop in the city to fight a squad of Dominators, while Barry and Supergirl eventually split off to plant devices made by Martin Stein/Firestorm that would cause all Dominators to experience serious mental stress and agony. At the same time, the meta-bomb is dropped, and Cisco and Sara try to use the Waverider tractor beam to stop it, but it only slows it down. Stein fuses with Jefferson "Jax" Jackson to become Firestorm, and they fly up to the bomb and hopefully transmogrify it into the water. Despite Jax's doubt that he could do it, he pulled it off with Stein, turning it to water and saving the meta-humans. Meanwhile, Felicity activates Stein's devices, causing the Dominators great agony and forcing them to retreat.
After the Legends have broken time, a dominator-baby is displaced in time and found on Earth by a young Ray Palmer. Lacking friends, Ray takes him in which proves to be a problem when the baby's mother comes to Earth in search of her child. While Sara is captured by the Mother Dominator and the beast sets out to find her child at Palmer's house, the baby is captured by a government organization. Nate and Amaya can lure away the mother dominator while the grown-up Ray and Zari save the baby. They reunite the two, after which the two Dominator's teleport away from Earth.
- Their language was described in the Arrow portion of the crossover as being like that of an ancient Hebrew dialect, suggesting that they have been to Earth long before 1951.
- One Dominator appears as a slaver in the second season of Supergirl.
- Zari saving Ray and the young Dominator by using her wind-powers to levitate Ray's bike is a reference to a famous moment in E.T.
- In the 2017 Arrowverse crossover, Kara fights another stray Dominator shortly before heading to Earth-1 for Barry's and Iris' wedding. After knocking out the Dominator, she says "These guys are so last years", referring to the fact that the Dominators were fought in the 2016 crossover.