The Fenrisulfr (Fenris-Wolf, Wolf of Fenrir, or Fenrir), was a monstrous wolf, one of the three offspring of Loki and the giantess Angrboda - the other two were the Jörmungandr (the Midgard Serpent) and Hel.

It was prophecised that the children of Loki and Angrboda would bring trouble to the Æsir so Odin had them brought to him, and after casting Jörmungandr into the sea and Hel into Niflheim, the land of the dead, Odin had the wolf raised among the Æsir, where only the god Týr dared go to him to give him meat.

"But when the gods saw how much he grew every day, and when all prophecies declared that he was fated to be their destruction, then the Æsir seized upon this way of escape: they made a very strong fetter, which they called Lædingr, and brought it before the Wolf, bidding him try his strength against the fetter."

"Allfather sent him who is called Skírnir, Freyr's messenger, down into the region of the Black Elves, to certain dwarves, and caused to be made the fetter named Gleipnir. It was made of six things: the noise a cat makes in foot-fall, the beard of a woman, the roots of a rock, the sinews of a bear, the breath of a fish, and the spittle of a bird. And though thou understand not these matters already, yet now thou mayest speedily find certain proof herein, that no lie is told thee: thou must have seen that a woman has no beard, and no sound comes from the leap of a cat, and there are no roots under a rock; and by my troth, all that I have told thee is equally true, though there be some things which thou canst not put to the test."

"The Wolf said: 'If ye bind me so that I shall not get free again, then ye will act in such a way that it will be late ere I receive help from you; I am unwilling that this band should be laid upon me. Yet rather than that ye should impugn my courage, let some one of you lay his hand in my mouth, for a pledge that this is done in good faith.' Each of the Æsir looked at his neighbor, and none was willing to part with his hand, until Týr stretched out his right hand and laid it in the Wolf's mouth. But when the Wolf lashed out, the fetter became hardened; and the more he struggled against it, the tighter the band was. Then all laughed except Týr: he lost his hand.

When the Æsir saw that the Wolf was fully bound, they took the chain that was fast to the fetter, and which is called Gelgja, and passed it through a great rock--it is called Gjöll--and fixed the rock deep down into the earth. Then they took a great stone and drove it yet deeper into the earth--it was called Thviti--and used the stone for a fastening-pin. The Wolf gaped terribly, and thrashed about and strove to bite them; they thrust into his mouth a certain sword: the guards caught in his lower jaw, and the point in the upper; that is his gag. He howls hideously, and slaver runs out of his mouth: that is the river called Ván; there he lies till the Weird of the Gods. (ie, Ragnarok)."