Wolf of Hell.
The Red Maw.
Jaws of Thirst.
Greatest of all wolves. Door warden of Angband. Morgoth chose one of the whelps of Draugluin and fitted him with living flesh and gave powers to him. Carcharoth grew fast: huge and hungry was he lying before the throne of Morgoth, and he became filled with a devouring spirit, tormented terrible and strong. Morgoth sent him to lay in watch before the gates of Angband to guard them.
In F.A.466, Beren and Luthien came to the gates where Carcharoth guarded the Doors of Hell. Beren was clad in the pelt of Draugluin and Luthien wore the cloak of Thuringwethil. Luthien commanded Carcharoth to sleep and he fell as one struck by lightning. When Beren and Luthien returned from the deep of Hell, they were waylaid at the gate by Carcharoth who had awakened. He attacked Luthien, but Beren tried to stop him by running in front of her lifting the Silmaril with his right hand. Carcharoth bit off Beren's hand at the wrist, and swallowed both the hand and Silmaril. The Silmaril filled his insides with a flame of anguish and seared his accused flesh: howling, he fled before them. Carcharoth became so filled with terrible madness that all living fled far away. In his madness, Carcharoth ran in a frenzy from the North and passed Taur-nu-Fuin. At length, he burst into Doriath from the eastern side of the river Esgalduin.
As Carcharoth drew near to Menegroth, a hunting party was gathered to destroy the dangerous wolf. Thingol, Mablung, Beleg, Beren and Húan rode forth in the morning. They crossed the river, and came upon Carcharoth in a valley at the falls of Esgalduin. Húan chased Carcharoth out of hiding and Carcharoth leapt upon Thingol. Beren strode before Carcharoth with a spear but Carcharoth avoided it. Carcharoth fell, with Beren biting into his breast. At that moment, Húan attacked Carcharoth from behind and they fought to the death. Húan slew Carcharoth but was mortally wounded himself.