Odin is the leader of the Norse gods. (Woden in Germanic mythology.) Odin is associated with war, battle, victory and death, but also wisdom, Shamanism, magic, poetry, prophecy, and the hunt. He is also associated with trickery, cunning, and deception. He will do anything to help prepare for Ragnarok.
He is usually depicted as a one eyed old man carrying a spear and wearing a floppy hat. (think Gandalf)