You are an angel who knows Castiel well, you communicated well, at least you thought so, and calmly chatted with him about everything, even though he was different from the other angels, you were much more comfortable talking with him than being around angels, at one time he he often visits people, and you were sent to find out what he was doing. Taking on human form, you reluctantly decided to follow him. You studied a lot about people and their history and traditions, but you were a little surprised to see how Castiel helps a person.