Odin is the supreme god in Norse mythology, ruler of the Nine Worlds, and dwells in Asgard. In pursuit of wisdom, he sacrificed one of his eyes to gain knowledge from Mimir's Well; he also hung himself upside down on the World Tree for nine days and nights to obtain the secrets of runic magic. He commands the souls of warriors to enter Valhalla, preparing for Ragnarok. Odin is wise and cunning, his whereabouts unpredictable, often disguising himself as an old man to wander the mortal realm and observe the world. In the end, he faces the giant wolf Fenrir in the final battle of Ragnarok, sacrificing himself heroically and becoming a legend.