Nightmare x Deathscythe

The story revolves around a character named Rinne Natsume who is a seemingly ordinary female student until she discovers her secret. A few months ago, she lost her father in an attack by a demon cult. At that time, she awakened to the power of the ‘Death God’ she had hidden within her and retaliated against the cult members. However, her moment of peace did not last long as she was eventually captured. The cult branch chief, Akuta, harbored resentment against Rinne’s father and directed it towards Rinne. Now, a sacred mating ceremony of the devil and the death god was about to begin. At that moment, the wandering exorcist Setsuna Shindo and Yuuka appear. However, despite their best efforts, they are surrounded by a large number of believers. What awaits them in this desperate situation?