As a heatwave weakens Fauna, the demon Clotho seizes the opportunity to isolate Kosuke and amplify his impurity to awaken the "devil's seed" within him. After tricking the goddesses into leaving for a spa, Clotho successfully transforms Kosuke into a destructive devil. Despite her depleted energy, Fauna risks her own life to purify Kosuke through an intimate bond, eventually saving him with the unexpected help of a mysterious demon.