Mari Kurihara is a third year student at Hachimitsu Academy and the president of the Underground Student Council, a secret organization that governs the school from behind the scenes. She is also the daughter of the school chairman and the older sister of Chiyo Kurihara. Mari is known among students for her wealth, beauty, and social power, and she is frequently described as one of the most beautiful girls in the school. Her nickname is Crow User Mari, reflecting her unusual ability to control and communicate with crows, which she uses for intimidation, surveillance, and assistance.

Mari is proud, dignified, and exudes a natural sense of authority that earns her widespread admiration and respect. She initially harbors a deep and open disdain for men, rooted in a strained relationship with her perverted father. This misandry drives much of her early antagonism toward the male students. However, beneath her stern and cold exterior, she possesses a genuinely kind and nurturing side. She showed this kindness when she helped a younger Meiko Shiraki gain confidence and prevented Kate Takenomiya from bullying her in middle school. Mari’s catchphrase, As long as I’m here, underscores her protective nature toward her friends and subordinates.

Her motivations center on maintaining the traditional environment of Hachimitsu Academy and opposing the admission of male students, which she sees as a threat. As the head of the Underground Student Council, she devises elaborate schemes to enforce her vision, including using the school prison to punish rule breakers. Despite her authoritarian approach, her commitment and intelligence earn her loyalty from followers and grudging respect from rivals.

In the story, Mari begins as the main antagonist during the boys’ imprisonment, orchestrating their punishment. Over time, she transitions into a supporting character who allies with the boys and becomes the lead protagonist during the Sports Festival arc. This shift marks a significant character development: she learns to socialize and empathize with the male students and begins to reconcile her feelings toward her estranged father.

Key relationships include her close sisterly bond with Chiyo Kurihara, whom she shared her childhood with and remains protective of. Her friendship with Meiko Shiraki is central, as Mari acts as both a mentor and a confidante, helping Meiko grow into a confident and capable member of the Underground Student Council. Mari also confronts Kate Takenomiya over bullying, reflecting her protective nature.

Development is most notable in the exploration of her backstory, particularly her difficult relationship with her father, which adds layers to her character and explains her initial misandry. Through the series, she begins to soften, reconciling with family members and the male protagonists, and grows emotionally as she learns to trust and cooperate with others.

Mari’s notable abilities include her exceptional intelligence and strategic thinking, athleticism and physical prowess, mastery of aikido, and her unique crow manipulation. She also demonstrates strong leadership and charisma, allowing her to command the Underground Student Council effectively. Her calm and controlled demeanor, combined with her cunning, makes her a formidable opponent and a valuable ally.