"Supergirl" will kick off The CW's four-part crossover on Nov. 28. YouTube/The CW Television Network

A new trailer of “Supergirl” was just released, and it introduced the show’s audience to the Dominators. As the tipping point of The CW’s four-part crossover draws nearer, it is vital to get an understanding of the invading alien race.

Watch the “Heroes vs Aliens: The Dominators” trailer

READ: The CW crossover to begin on Nov. 28 with 'Supergirl,' followed by 'The Flash,' 'Arrow' and 'Legends Of Tomorrow'

Created in 1967 by Jim Shooter as part of the “Adventure Comics” world, the Dominators belong to an empire called Dominion. In this empire, social status is denoted by the size of a red circle on an individual’s forehead. Described as emotionless and calculating, the aliens' main goal is to use their knowledge of genetic manipulation in order to enhance their own abilities. The same were illustrated by Shooter and Jim Mooney, which Deadline has noted as the inspiration of The CW.

After the Dominators were introduced, they were used just sparingly until their return for a three-part miniseries in 1989, entitled “Invasion.” Not only did the comic bring back the alien race, but it did so in the 20th and 30th centuries, as noted by CBR. Furthermore, the miniseries touched just about every DC universe that existed at the time -- which is fitting for The CW crossover.

In “Invasion,” the Dominators gathered other alien races to fight in their battle and were the true masterminds behind the war. It was their belief that mankind had a metagene in their DNA, which would eventually activate in all humans. Once this metagene is activated, humans would have access to a wide range of superpowers, which was of course a threat that the Dominators would prefer to extinguish first.

READ: 'Supergirl' season 2 episode 7 spoilers: Kara goes head-to-head with Cyborg Superman; James Olsen takes on a new identity as ‘Guardian’ in ‘The Darkest Places’

The CW crossover begins on Nov. 28 with an episode of “Supergirl.” It will continue on in the week’s episodes of “The Flash,” “Arrow” and “DC’s Legends Of Tomorrow.” Australian audiences can catch the same on Fox 8.