In Norse mythology, Fenrir is the giant wolf prophesied to kill Odin during Ragnarök.
Fenrir, also called Fenrisúlfr or the Fenris-wolf, is the son of the god Loki and the giantess Angrboða. His siblings include Hel, ruler of the underworld, and Jörmungandr, the Midgard Serpent. The gods fear Fenrir because prophecies foretell the destruction he will cause.
They try to restrain him with increasingly strong bonds. The magical ribbon Gleipnir finally holds him, but only after the god Týr places his hand in Fenrir’s mouth as a pledge. When the wolf realizes the gods have deceived him, he bites off Týr’s hand.
At Ragnarök, Fenrir breaks free and swallows Odin. Odin’s son Víðarr then avenges him and kills the wolf, traditionally by forcing open Fenrir’s jaws. Fenrir is distinct from Sköll and Hati, wolves associated with chasing the Sun and Moon, and from Garmr, the monstrous hound who fights Týr.