Aria Shichijō serves as the student council secretary at Ōsai Academy, advancing from her second year to her third year. She comes from the wealthy and influential Shichijō zaibatsu family, a background that often leaves her with gaps in everyday knowledge—she expects manual doors to open automatically and stationary stairs to move like escalators. Despite these airheaded tendencies, she excels academically, consistently ranking second in her year behind Shino Amakusa. Aria has light brown hair with bangs covering the right side of her face, pale skin, light brown eyes, and a buxom figure that is the most developed in the series. She stands 168 centimeters tall. Her outward demeanor is calm, gentle, and motherly, and she generously uses her family’s wealth to fund student council activities and group outings. Underneath this composed exterior, she harbors intense perverse interests that include bondage, exhibitionism, and the sexual use of enemas, which are implied to stem from early childhood exposure to adult materials. She typically wears a chastity belt, with the key held by her maid, Sayaka Dejima, who shares similar inclinations. Aria is close friends with Shino, and their mutual tendency toward sexual humor often forces Shino into the straight-woman role. Her interactions with fellow council member Takatoshi Tsuda are marked by caution on his part once he recognizes her perverse nature. Her maid Sayaka Dejima shares a distinctive rapport with her, built on mutual understanding and shared interests.