Fenris (also Fenrir, Fenrisúlfr) the giant wolf was the son of the evil god Loki in the Norse mythology. The gods feared his strength and bounded him with a mystical ribbon. While struggling to free himself he bit off the hand of the god Tyr. He now waits for the time of his freedom, Ragnarok, where ,it is prophetised, that he will fight and slain Odin. At the end of the battle Odin's son Víðarr will kill Fenrir and have his revenge for his father's death.

source: Poetic edda 13th century