Wanting to bring in Christian mythology to the series, the writers created the angel Castiel. With Kripke wanting to keep the introduction of an angel a secret, the character was instead described as a demon during auditions. Misha Collins was cast as the character. Making his debut in the fourth-season premiere, Castiel resurrects Dean from Hell after his death in the third season, and comes to be an ally of the Winchesters. The character was originally intended for only a six-episode story arc, but the role was later expanded. Collins was promoted to a series regular for the fifth and sixth season, something Collins believes to be mainly due to fan support. Collins was downgraded to recurring status for the seventh and eighth seasons, but returned to series regular status for seasons nine and ten.