Manabu Horikita, older brother to Suzune Horikita, served as Student Council President during his time at Advanced Nurturing High School. He possesses a tall, well-built frame, short black hair swept left, violet eyes, and wears square-rimmed glasses alongside the standard uniform. His martial arts expertise includes a 5th-Dan in karate and a 4th-Dan in aikido—high ranks for his age—demonstrated when he attacked Kiyotaka Ayanokōji, who evaded the strikes. Serious, intelligent, and deeply dedicated to his presidential role, Manabu prioritizes his reputation and legacy. This drove his initial contempt for Suzune’s placement in Class D, viewing it as a threat to his standing. He demanded her withdrawal to avoid tarnishing his name and nearly assaulted her before Ayanokōji intervened. Despite his stern demeanor, he acknowledges talent, praising Arisu Sakayanagi and Kōhei Katsuragi academically. He also develops respect for Ayanokōji post-confrontation, offering him a Student Council position—which Ayanokōji declined. Perceptive, Manabu deduces Ayanokōji manipulated entrance exams for uniform mediocrity and suspects his involvement in resolving Ken Sudō’s complaint. He challenges authority openly, criticizing Sae Chabashira during Sudō’s disciplinary hearing. His leadership employs intimidation when necessary, like quelling a near-fight at the pool by reminding students they remained on school grounds. Manabu’s relationship with Suzune starts adversarial due to her Class D status. He criticizes her antisocial tendencies and academic performance but shows subtle shifts witnessing her determination to elevate Class D, particularly during her speech about reaching Class A. Post-graduation, their dynamic evolves when Suzune calls him "the one person she could trust" confronting Kikyō Kushida. Rising to Student Council President earned Manabu widespread respect. His family background is minimally detailed, though Suzune’s childhood portrait implies a closer past bond. After graduating, he worries about the school’s direction under new president Nagumo Miyabi, fearing abusive power. He enlists Ayanokōji’s help to investigate Nagumo, leveraging their prior connection. In his final school days, Manabu meets Ayanokōji privately, expressing regret over not curbing Nagumo’s influence. He hints at viewing Ayanokōji as a protégé, though their collaboration remains unresolved, reflecting his enduring investment in the school’s future and recognition of Ayanokōji’s capabilities. Manabu’s overarching motivation is leaving a legacy of excellence, aspiring to be remembered as a role model who elevated the institution.