Dominators

"But what happens when a man like him inherits abilities like yours? We have seen it happen on countless other worlds, which is why we must exterminate your kind before the scourge of your planet becomes the scourge of ours..."

- The Dominator Leader

The Dominators are a hostile alien species first encountered in Adventure Comics Vol.1 #361.

The Dominators are a race of conquerors that live on their home world, Dominion, thousands of light years from Earth. The Dominator’s divide their society into a caste based structure with the superior caste elders being in charge of the Dominion. Hierarchy is determined by the size of the red disk worn on the forehead. Their society believes themselves to be highly evolved beings and any thoughts of further evolving their form’s is thought of as heresy.At some point, a low caste Dominator scientist studied the Metagene that seemed prevalent amongst the inhabitants of the planet Earth and concluded that the Human race along with its superheroes posed a threat to the future of the Dominion. This led to the Dominators embarking on an ambitious plan to contain the human threat.

TV appearance
The The Dominators made an appearance in the animated series Legion of Super Heroes.

The Dominators are villains in the Arrowverse. They are the main villains of the 2016 crossover of the TV shows The Flash, Arrow, Legends of Tomorrow and Supergirl. In 2016, the appearance of meta-humans draw the Dominators to earth as they fear that meta-humans might become a threat in the future. They land their ships on Earth and kidnap the US president. When a hero force consisting of Team Arrow, the Flash and his team, the Legends and Supergirl, sets out to save the president, the Dominators use a mind control device on them. They take control of all heroes, except the Flash and the Green Arrow, and also kill the president. Eventually, the heroes are pitted against Barry and Oliver and Barry manages to trick Supergirl into destroying the control device, saving all heroes from the Dominator influence. Although they cannot further control the heroes, the Dominators manage to teleport Oliver, Diggle, Thea, Felicity, Sara and Ray Palmer onto their mothership where they put the group in a collective hallucination. The group manages to escape the hallucination and flee back to earth, using an escape pod from the alien mothership. However, in the meantime the Dominators have created a weapon of mass destruction, threatening to destroy earth should Barry Allen, whom the Dominator deem the biggest threat, not surrender himself. They drop the bomb, which is picked up by the Waverider. At the same time, a group of Dominators fight the heroes but Barry places the high-frequency transmitting devices made by Martin Stein on the Dominators, and Felicity detonates them, effectively taking the Dominators out. After their defeat, the Dominators retreat from Earth.

Trivia

 * Supergirl knows the Dominators, claiming that the aliens have attacked Krypton.