Fenrir

The Great Wolf Fenrir is an S-Rank magic beast. It perished in the Demon Wolf's Garden, where its magical influence still lingers.

Norse Mythology
In Norse Mythology, Fenrir (alternatively called Fenrisúlfr) was a wolf of calamity birthed by the trickster god Loki and a giantess, Angerboda. He is a brother of the same mother to the serpent Jormungand and underworld goddess Hel. With the knowledge Loki will only bring destruction with his bountiful strength, the gods decided to chain him. Convinced it is a test of strength by conniving gods, Fenrir breaks free of the fetters easily. In response, the gods had the dwarves forge the strongest chains ever built and presented the light-looking chains to Fenrir. Fenrir, now suspicious, only agreed to the "test of strength" a third time on the condition one of the gods placed his or her hand in his mouth. The only god brave enough to step up, knowing he or she would lose a hand, was Tyr. Sure enough, he lost his hand, and the howling Fenrir had his jaws propped open with a sword. Chains now tied to a boulder, Fenrir's drool from howling created a foamy river called Expectation. When Ragnarök arrived, Fenrir broke from his chains and devoured everything in his path. He kills the chief god Odin, whose son Vidar slays him in vengeance. Another side to the story is Fenrir may have committed no evil originally, but did after he was chained.