Woden, or Odin, first appeared in episode XXXVII: The Birth of Evil, was portrayed as the powerful Norse god of war, wisdom, battle, and death and seemed to carry an air of benevolence and wisdom as well as respect an awe at the power he wields. His appearance was similar to a viking as he was wearing a golden-white tunic, a large helmet with wings he also had a blond beard and an eye patch over one eye. During the battle against the dark creature in space, he rode on his eight-legged horse Sleipnir.
Millions or billions of years before Jack was even born, Odin, along with his fellow gods, Ra and Vishnu, were battling a great evil entity somewhere at the strange outer space. Their divine weapons injured and burnt the great evil in the same way as Jack's katana did, but, given the regeneration power the entity possessed, the attempts to destroy it was extremely difficult, since the substance was difficult to destroy even through the use of collaborative attacks. In the battle, Odin cut off a part of the entity with his Gungnir but the divine power of it didn't destroy the severed part completely, allowing it to drifted away from the scene, unnoticed by them.
For eons, the part floated in the outer space and accidentally (or fated?) to land on prehistoric earth, wiping out all the dinosaurs, and then appeared as a pool of tar.
Powers and Equipment
As a God, Odin wields a great amount of power enough to destroy a being as powerful as Aku;something only fellow deities, or those who could wield the mystical sword could accomplish.
Gungnir blasts: Odin wields a powerful spear, called Gungnir, that he uses to channel his power in the form blue meteor like blasts that are capable of damaging Aku.
Eyebeams: Odin, along with Ra and Vishnu are capable of summoning the very essence of purity and righteousness from within the Emperor.
Shapeshifting: As a god, Odin are able to change his form and appearance at will, e.g. a Buddhist monk.
Cosmic Knowledge: He is aware of Aku's rise on Earth. He assumes the form of a Buddhist monk and forges the Emperor's essence of virtue into a katana, showing that he is knowledgeable of Japanese culture and Buddhism, and also his respect of them.
Immortality: As a divine god, like any spirit or soul, Odin is immortal and cannot apparently die.
Astral projection: During the forging scene, he is capable of projecting his spirit in a form of a Buddhist monk to forge the katana, while his main body is seen behind, glowing in blue.
Transmutation: He and His fellow gods transmuted strength and purity of Emperor of Japan's soul into a steel katana.