Most aliens are from different planets, who have a source of origin near the Solar System and in the Milky Way Galaxy, although, unlike the Marvel Universe, alien colonies are common within the solar system. The Dominators are an imperialistic race of terrorist aliens who control most of the unknown cosmos in order to extract genetic resources from planets. The caste is also collectively known as the Dominion. Other aliens in the outlying galaxies control armadas like the Khunds, Gordanians, Thanagarians, Spider Guild and, most recently, the Reach. Even though the majority of the DC Universe is policed by the Green Lantern Corps, and later the United Planets, most rogue races strive to conquer the known universe.