Fenrir

Fenrir, sometimes Fenrisulfr, is a wolf out of Norse mythology. Fenrir is the offspring of the trickster god Loki and the giantess Angrboða. He had a brother named Jörmungandr and a sister who was called Hel. Fenrir, himself has two sons named Hati and Skoll. Hati is said to chase Máni, the god of the moon, while his brother chases the horses Árvakr and Alsviðr that pull the chariot of Sol, the Sun. The name Skoll has sometimes been used to refer directly to the wolf Fenrir and not to the son.

A prophecy informed the gods that the children of Loki and Angrboða would bring them great trouble. Jörmungandr was cast into the sea, where he grew so long that he could wrap around the world and touch the end of his tail thus earning the name the Midgard Serpent. Fenrir's sister, Hel, was sent to rule over the land of Hel, the Norse underworld. The god Odin then said that Fenrir would be raised among the Æsir, the principal gods of Morse mythology. Only the god Týr would feed the wolf.

Due to the prophecy and the wolf's own increasing strength, the gods tried to bind him. Fenrir let them chain him up twice, and broke out both times. Odin then contracted the dwarves to construct bindings that the wolf could not escape. They produced a chain made up of the sound of a cat's footfall, the beard of a woman, the roots of a mountain, bear's sinews, fish's breath, and bird's saliva. Fenrir let the gods put this chain on him as a test to see if he could break it. As a show of good faith on the part of the gods, Týr placed his hand in the wolf's mouth with the understanding that if the gods did not release him, Fenrir would take the hand. Fenrir struggled but could not get free. The gods denied to free him and the great wolf bit off Týr's hand.

It has already been foretold, however, that Fenrir will outgrow any bounds the gods place on him and that, at the time of the Ragnarök, he will devour the god Odin and his sons will succeed in their quests, attempting to swallow the Sun and the Moon.

Source
Fenrir; Wikipedia