Draugluin was the sire of the werewolves of Angband, the dread wolf of Sauron, whom Sauron kept on Tol-in-Gaurhoth, the Isle of Werewolves. That isle was Tol Sirion, where Finrod had built a watchtower, until Sauron took it and filled it with fear.1,2
When Finrod Felagund and Beren, disguised as Orcs on the quest for the Silmaril, were taken by Sauron, they and their companions were thrown into the pits beneath the tower, and from time to time a werewolf devoured one of the companions.2
Lúthien came to the isle with the hound Huan to free Beren. Sauron sent his wolves out one by one to the bridge, and Huan slew them all. Then Sauron sent Draugluin. The fight between the two was long and fierce, but at last Draugluin fled back into the tower and died at Sauron's feet, telling his master that Huan was there.2
Sauron then took the shape of a werewolf himself and came out to the bridge, and Huan overcame him too. Sauron yielded the tower to Lúthien and fled.2
Draugluin's body served one more purpose. Huan brought the hide of Draugluin and the bat-fell of the vampire Thuringwethil from the isle, and in these shapes, by Lúthien's arts, Beren and Lúthien passed through Anfauglith to the gates of Angband.2
Sources
Citations name the chapter rather than the page, so they work in any edition. The colour of each note shows what kind of source it is.
- Edited posthumously The Silmarillion, Unfinished Tales and Tolkien's late writings on the Elder Days, assembled by Christopher Tolkien from his father's papers.
- Edited posthumously The Silmarillion, Quenta Silmarillion, ch. 18, “Of the Ruin of Beleriand and the Fall of Fingolfin”
- Edited posthumously The Silmarillion, Quenta Silmarillion, ch. 19, “Of Beren and Lúthien”