User blog comment:Gcheung28/Submit Questions for Supernatural at SDCC/@comment-12891159-20130729185854/@comment-3045936-20130729221926

I always thought that as they barely got a new season for season 4, a  the ratings for season 3 were ok but not great. That, they decided to add angels then, as they already made it to where human souls, became demons. Kind of hard to say, that fallen angels were the original demons after that.