Luminoth is a conjunction of two words: luminous and moth. They are a tall and very intelligent race on the planet Aether. However, their origin lies on no planet but rather among the stars. According to their historical documents, they have met the Chozo and similar sentient races with whom they appear to have formed a not only a mutual admiration, but an exchange of technology and ideas. It was in fact the Chozo who inspired their quest for a planet to call home. They upgrade Samus Aran's Power suit in the Nintendo GameCube video game Metroid Prime 2: Echoes in order to help protect her in battle.

U-Mos is the last Sentinel of the Luminoth and the only guide in her mission. The Luminoth race was almost completely wiped out in their war with the Ing, creatures hailing from Aether's twisted mirror, Dark Aether. To Protect the last few members of their race, U-Mos ordered all remaining living Luminoth to be contained in stasis tanks within the Great Temple until the Ing are taken care of.