Original title: 悪魔聖女 ～デーモンガール・ステップ～
Ruti is a demon who was vanquished a long time ago and a part of him was sealed away. Now in the present, he was resurrected by the pitiful Kyouka who mistakened him for a sex toy. He hatched a plan to train her as the evil mahou shoujo Dark Cherry and collect magical energy to fully regain his form. However, three figures of justice stood in their way: mahou shoujos Melody Queen, Lionel and Aya.