Castiel

Possibly a variant of Cassiel. It is the name of an angel in the grimoire the Heptameron, a work that is sometimes (probably incorrectly) attributed to the 13th-century philosopher Pietro d'Abano. It was also the name of a character (an angel) on the American television series Supernatural (2005-2020). The creator Eric Kripke chose it after an internet search revealed that Castiel was an angel associated with Thursdays, the day the show aired [1].