Mizuki Kudo (17 years old) 166cm / approx. 50kg. The leader of the First Tier girls and very vain. She is highly concerned with her status and how others perceive her. An athletic type who is also active in the track team.

Rikako Hatori (17 years old) 153cm / approx. 43kg. Short with a baby face. On the surface, she is a First Tier girl, but she is quite cynical about the relationships in class and questions the school caste system itself. She is skilled at the piano.

Moe Kokubun (17 years old) 160cm / approx. 48kg. Positioned as Mizuki's follower. The ace of the track team with high athletic ability. She begins to have doubts about her relationship with Mizuki and starts to distance herself later on.

Yuna Izumi (17 years old) 164cm / approx. 49kg. One of the First Tier girls. She usually hangs out with Mizuki, Moe, and Rikako, and is the type to go along with the atmosphere of the top of the school caste.

Age: 35 Height: Approx. 168cm (estimated) Weight: Low 50kg range (estimated) Personality: Calm, dignified, and indifferent to the gaze of others. She is quite free-spirited and the type to speak her mind clearly. She confronts the high schoolers' caste system and bullying from an adult perspective, piercing through to the heart of the issues. While usually aloof, she actually carries deep scars from her own past school life.

Masamitsu Tsuchiya (18 years old): 175cm / approx. 65kg. The leader of the First Tier boys. Forceful, tyrannical, and very dominant. While he mocks and corners others, he also has a side that reflects on his actions toward the end.

Osamu Yukawa (18 years old): 175cm / approx. 60kg. Light-hearted with a good vibe, he is the mood maker of the boys' group. While he goes along with Tsuchiya, he is actually the type who worries deeply about being betrayed by others.

Ren Azuma (17 years old) Height: Approx. 170cm (estimated) Weight: Approx. 55–58kg (estimated) Personality: Quiet and cool-headed. A First Tier boy who hangs out with Tsuchiya and Yukawa, but isn't the type to step forward and dominate like Tsuchiya. A boy with long hair and a somewhat unique aura.

Age: 17 Height: Approx. 165cm (estimated) Weight: Approx. 50kg (estimated) Personality: Quiet and reserved. She is isolated in class and tends to try to conform to those around her. She begins to change little by little through her involvement with Ayako.

Ai Yamashita — Former First Tier. She acts like a bright mood maker but is looked down upon and used by the First Tier girls. Ayako's second friend. Ryota Otake — A boy in a band. He is close friends with Teppei Saegusa and becomes Ayako's friend. Teppei Saegusa — Otake's bandmate. He is targeted by the First Tier boys due to his relationship with Otake. Ryo Akutsu — A quiet boy with excellent grades. He plays an important role outside of the school caste system. Hitomi Eto — A Second Tier girl. She worries about the relationships in class while interacting with Ayako and the others. Mai Yuki — A Second Tier female student.