Uldor

called the Accursed, son of Ulfang the Black.

An Easterling who swore alleigance to Caranthir but became the 'leader in treason' and broke that oath in the NirnaethArnoediad. He delayed Maedhros from entering the battle with false warnings of assault from Angband, and he and the men who followed him went over to the side of Morgoth, attacking the host of Maedhros. He was slain by Maglor.