Malraugin was one of the Balrogs created by Morgoth. He served in the Valaraukar, an order of Balrogs in Morgoth's service. He was also one of those that fought in many battles of the War of the Jewels, up to and including the War of Wrath. He somehow managed to survive Morgoth's defeat, fleeing east and taking refuge beneath the Misty Mountains. News of the disaster reached the Silvan elves of Lothlórien, who called Malraugin the Nameless Terror (not knowing its true nature at the time), and who began to refer to Khazad-dûm as Moria (dark abyss).