高宮 紗月

The protagonist's mysterious older sister who controls the dark side of the school.

A third-year female student at Tatsuryou Academy. She is Ryo's older sister, and like Ryo, she is a descendant of the school's founder. She is a brilliant, sociable, and talented girl.

However, she has a mysterious charisma that never ceases to attract people, and due to her lineage she is famous not only within the school but also outside of it. She is a central figure in the "behind the scenes" of the school, that centers around the old school building.