Coming from the outer cosmos of the DC Universe, they are highly technologically advanced, and live in a rigid hierarchical society, in which one's caste is determined by the size of a red circle on one's forehead.

crossover event involving many of DC's superhero comics set in the present, written primarily by Keith Giffen and Bill Mantlo and featuring art by Todd McFarlane.

[4] Originally depicted as having light blue skin with a white circle on the forehead denoting their social rank,[5] their later more villainous designs with yellow skin and a red circle – introduced in the 1970s[4] and accentuated in the 1980s[4] – has drawn comparisons to "Yellow Peril" stereotypes of east Asians, citing features such as "bald heads, slanted, narrow eyes, long, claw-like fingernails, and dressed in robes".

Their primary motivation for this was their concern at the genetic potential of humanity, as evidenced by the large number of super-powered beings on the Earth of the DC Universe, also known as the metagene.

After freeing them, Valor helped settle these modified humans on various worlds which eventually became many of the homeworlds of members of the Legion of Super-Heroes, such as Bismoll, Cargg, and Braal, amongst others.

Later, during the Earthwar, the war expanded involving the Khunds, the Dark Circle, and even Mordru, but at the end of it a peace treaty was finally achieved with the Dominion.

Their role was known only to a few, including Dirk Morgna (Sun Boy), a now former Legionnaire who was hired by the Dominator controlled EarthGov as a public relations liaison.

Meanwhile, on Earth, there was an underground resistance movement including ex-Invisible Kid Jacques Foccart, the former Legion of Substitute Heroes, and their unlikely ally Universo.

This backfired when an insane Dev-Em seized control of the system, and though he was prevented by the members of the Legion and a time-lost Superman from detonating it, one of the Linear Men eventually did, causing a huge catastrophe on Earth.

[volume & issue needed] In the "Threeboot" version of Legion continuity, the Dominators were inspired to invade Earth when a time travelling Booster Gold inadvertently led them to believe that fifty-two planets were planning an attack on the Dominion.

They managed to seize control of Earth's technology, and sent genetically modified warriors (created using gene grafts from the former members of Terror Firma) through a stargate.