User blog comment:ImperiexSeed/Supernatural Mysteries/@comment-1509826-20120313193555/@comment-3481504-20120313204108

Not sure, but I'm certain no such confirmation was given in an interview, I could be wrong here, but I doubt it.

If I were to take a guess, maybe magic or the gods, but again, nothing's for sure. About how The Trickster become an angel., I think they found he was too powerful to be one, and with the Archangels in the fifth season, decided to make him one.