Castiel

Means "shield of God" in Hebrew via El theophory in the Bible, which is the practice of embedding the name of a god or a deity in, usually, a proper name. Castiel is sometimes considered a variant of Cassiel. The name Castiel does not appear in the Bible, nor does it appear until around the 13th century. Later texts say Castiel is an angel who presides over Thursdays, and it is likely he came to be based on an older mythological character (likely Cassiel).

In the CW television show 'Supernatural', Castiel is the name of a protagonist portrayed by actor Misha Collins. Castiel is an angel who befriends the main protagonists Sam and Dean Winchester. Modern usage of the name may be due to this character.