Odin — Old Norse Óðinn, from óðr meaning "fury," "inspiration" or "poetry" — is the chief of the Aesir gods in Norse mythology and the father of many divine and heroic figures. He is known by over 200 names in the Norse sources — each reflecting a different aspect or role: Allfather, Wanderer, One-Eyed, the Hanged God, Raven God, Lord of the Slain, Deceiver, God of the Gallows. This multiplicity of names is itself significant: Odin is a shape-shifter, a god who cannot be fixed or contained, who appears in different guises for different purposes.
He is typically depicted as a tall, old man with a long grey cloak, a broad-brimmed hat pulled low over his face, carrying the spear Gungnir — and with one eye, the other sacrificed at Mimir's well. His single eye sees everything in the physical world; the missing eye sees into the hidden depths. He travels through the nine worlds accompanied by his ravens Huginn (Thought) and Muninn (Memory), his wolves Geri and Freki, and rides the eight-legged horse Sleipnir — the fastest of all horses, born of Loki's shape-shifting and able to travel between worlds.
Unlike the Norse thunder god Thor — whose popularity and straightforwardness made him the most widely worshipped of the Norse gods among ordinary people — Odin was primarily the god of kings, warriors, poets and skalds. He is the patron of those who pursue excellence at extreme cost, who seek knowledge that ordinary mortals cannot bear, who operate at the edges of what is humanly possible. He is not a comfortable god to worship; his favours are capricious and his chosen ones tend to die young and gloriously.
His hall is Valhalla — the Hall of the Slain — where he gathers the finest warriors killed in battle, the Einherjar, to feast and fight each day in preparation for Ragnarök. The Valkyries — his battle-maidens — choose the worthy dead and carry them to Valhalla. But Odin's purpose in gathering this army is not triumphalist: he knows from the prophecy of the völva (the seeress) that at Ragnarök, the Einherjar will fight and lose. He gathers them not for victory but for the best possible defeat.