Justin Martyr on Angels, Demons, and the Devil from the series Justin Martyr: The Man and His Theology by Robert Alan King is a booklet with over 3,100 words. This booklet discusses Justin's beliefs about angels, demons, and Satan. This includes a thorough examination of his views on how demons are working in the spiritual world to wreck havoc upon mankind. Robert Alan King is an ordained minister through Calvary Chapel who has spent years studying the writings of Justin Martyr.