User blog comment:Monkey d strawhat/Demons in one piece/@comment-4161592-20120319183720

My answer is NO.

Oda himself said that he' s not a very religious person, not much religion stuff involved in here anyway. Again there wont be real demons/spirits appearing as characters, they could be mentioned actually for any sort of legend or myth for example, but not take place or participate in the story of One Piece.