In Norse mythology, the monstrous wolf who is Loki’s son and destined to kill Odin is Fenrir.
Fenrir is one of the three famous children of Loki and the jötunn Angrboða, alongside Hel and Jörmungandr. The gods grew fearful after prophecies foretold the destruction associated with Loki’s children, so they brought Fenrir to Asgard and tried to restrain him.
The gods’ first chains failed, but the dwarfs forged Gleipnir, a magical fetter made from paradoxical ingredients such as a cat’s footfall and a bird’s spittle. Fenrir agreed to be bound only if a god placed a hand in his mouth as a pledge. When the gods would not release him, Fenrir bit off Týr’s hand.
At Ragnarök, Fenrir breaks free and fights Odin at Vígríðr. The wolf swallows and kills Odin, fulfilling the prophecy, but Odin’s son Víðarr avenges him and destroys Fenrir. Garmr is a separate monstrous canine in the surviving texts, while Jörmungandr is Loki’s serpent child and Sköll is one of Fenrir’s wolf offspring.