Castiel is an angel from Heaven. He is a "Valkyrie"-type angel (an eldritch being created by God for combat, unlike the more peaceful "Goddess" angels). He came down to Earth to help the Winchester brothers, Sam and Dean, fight demons, ghosts, vampires, werewolves, and the forces of darkness. He has vast divine powers at his disposal, and a wealth of information about the supernatural and the divine. Despite his often surly demeanor, he is still noble and friendly, and wants to protect the innocent and defeat the forces of evil, no matter the cost.
A magic spell brought him to the Scooby Doo Universe, where he helped Scooby and his friends defeat an evil ghost.
