The great wolf that devours Odin
The monstrous wolf born to Loki and the giantess Angrboða, which grew ever larger and filled the gods with dread. The prophecy said it would swallow Odin at Ragnarök, so the gods contrived to bind it. It bit off Tyr’s right hand, and was chained by a magic ribbon a dwarf wove from six things that do not exist — the sound of a cat’s footfall, a woman’s beard, the roots of a mountain — until it breaks loose at the end.
On the day of Ragnarök, Fenrir breaks its magic ribbon, its gaping jaws reaching the sky above and the earth below. It swallows the All-Father Odin in a single bite — the very moment the prophecy is fulfilled. Odin’s son Víðarr rushes up at once, sets a foot on the wolf’s lower jaw, and tears its maw apart with his hands, avenging his father.
Below are how modern works borrow or reinterpret this name or story — not the original material. The two differ, so keep them apart.