Odin

"I don't know what everybody's getting so worked up about. It's just a couple of angels having a slap-fight."

- Odin referring to Michael and Lucifer.

Odin  was the chief pagan deity of the Norse pantheon. While on Earth he took the form of an elderly American man in a bomber jacket and a strong Midwest accent.

Powers and Abilities
As a deity, Odin possessed several abilities common to his kind But as the king of the Norse gods, he was probably one of the most powerful pagan gods that have appeared in the show.
 * Immortality - As a god, Odin was not subject to old age or natural death and was probably over 5000 years old.
 * Invulnerability - Odin was immune to conventional weapons.
 * Super strength - Odin possessed superhuman strength, though he was still killed by the archangel Lucifer.
 * Weather Manipulation - Odin was able to lure Sam and Dean to him and the other gods by creating a storm.
 * Madic - As the god of madic, Odin possess incredible magical powers and knowledge.

Season 5
Odin was one of the gods who met with the other deities, to try to work out a way to stop the Apocalypse. He was of a laid back disposition towards the whole thing, believing it to be a "slap fight between a couple of angels".

This casual arrogance cost him his life when Lucifer killed him in the Elysian Fields Hotel hallway, presumably in a violent manner.

Trivia

 * It is unknown why he or Baldur did not see through Gabriel's disguise; it is possible that Gabriel had the ability to change their perception.
 * Odin claimed both the existence of Jormungandr and Fenrir. Additionally, he also mocked Zao Shen's world turtle, indicating it may also be existing or existed at one point in time.
 * Odin is said to be killed by the giant wolf Fenris during the battle of Ragnarok.  The Maw of Fenris was a werewolf cult in which Garth's mother-in-law and her relatives were members of in Sharp Teeth.

Appearances

 * Season 5
 * Hammer of the Gods
 * Season 9
 * Sharp Teeth (mentioned only)