The most sly and ruthless of the sons of Feanor, he was the organiser of the attempt to abduct Luthien so he could marry her and take over Doriath, thereby strengthening his forces enough to attack Angband. He also usurped rulership of Nargothrond from Orodreth after Finrod's disappearance. These acts were the main reason for the absence of forces from Nargothrond and Doriath at the Nirnaeth Arnoediad.
He also took part in battles to regain the Silmaril taken by Elwe, and he was slain, along with Curufin and Caranthir, in the battle against Elwing's forces. The sons of Feanor had waylaid the harmless elves in Arvernien in order to regain the jewel, which they refused to hand over.