Stretching back through the show's run, the Supernatural mythos has come far from the Winchesters just expelling demons. In the first season, the existence of angels was only hinted at. Flash forward a few years and Sam and Dean encounter their first descendant of Heaven, Castiel, whose true form is said to be as large as the Chrysler Building. Since season 4, angels have become routine fare for the Winchesters, although the celestial entities often far exceed the duo's typical foes in pure strength.

At the top of the heap are the archangels, the first four supreme creations of God, brought into existence briefly after the beginning of existence itself. After that, various tiers of power divide the guardians of Heaven, categorizing them into such classes as Seraphim, Cherubs, Grigori, and the dreaded Nephilim. Sometime after the creation of mankind, God asked his angels to become the protective watchers of Earth,...