A demon becomes a heroic, angelic/holy being. A demon with a good heart that was once evil. They may still act mean but is really a good person or at least trying to learn to become a good person. Thousands of years in hell has ingrained them to violence and they have to constancy fast back their evil violet urges and treat people with kindness. The more goodness and kindness they express the stronger holy power they can wield as they transform from demon to angel.