Loki and Angrboda make babies and have 3 fearfully hideous and strong children. The first was the serpent Jormungand, and the second was the death-goddess Hel. The third was the wolf Fenrir.
In order to keep these monsters at bay, they threw Jomungand into the ocean, where he encircled Midgard, the world of humankind. Hel they relegated to the underworld. Fenrir, however, inspired too much fear in them for them to let him out from under their watchful eyes, so they reared the pup themselves in their stronghold, Asgard.
Only Tyr, the indefatigable upholder of law and honor, dared to approach Fenrir to feed him. Fenrir grew at an alarming rate, however, and soon the gods decided that his stay in Asgard had to be temporary. Knowing well how much devastation he would cause if he were allowed to roam free, the gods attempted to bind him with various chains.
At last, the gods sent a messenger down to Svartalfheim, the realm of the dwarves. The dwarves, being the most skilled craftspeople in the cosmos, were able to forge a chain whose strength couldn’t be equaled; it was wrought from the sound of a cat’s footsteps, the beard of a woman, the roots of mountains, the breath of a fish, and the spittle of a bird.
When the gods presented Fenrir with the curiously light and supple chain, the wolf suspected trickery and refused to be bound with it unless one of the gods would lay his or her hand in his jaws as a pledge of good faith. The brave Tyr, volunteered to fulfill the wolf’s demand. And, sure enough, when Fenrir discovered that he was unable to escape from the chain, he chomped off and swallowed Tyr’s hand.
The fettered beast was then transported to some suitably lonely and desolate place. The chain was tied to a boulder and a sword was placed in the wolf’s jaws to hold them open. As he howled wildly and ceaselessly, a foamy river called “Expectation” flowed from his drooling mouth. And there, in that sordid state, he remained – until Ragnarok.