Fenrir (or Fenris) is a gigantic and terrible monster in the shape of a wolf. He is the eldest child of Loki and the giantess Angrboda. The gods learned of a prophecy which stated that the wolf and his family would one day be responsible for the destruction of the world. They caught the wolf and locked him in a cage. Only the god of war, Tyr, dared to feed and take care of the wolf.