Chizuko Hori, a first-year Odachi High student, serves as one of the sumo club’s managers. Her black hair flows into a chest-length fishtail braid over her left shoulder, accented by forehead bangs and chin-length side strands. Oval glasses frame her dark gray eyes, complementing her standard school uniform.

Introverted yet observant, Chizuko contrasts with her outgoing sister Honoka, though their bond remains unshaken. A pivotal train incident—where club member Hinomaru Ushio rescues her from harassment—ignites her admiration for him, driving her to join the sumo club as repayment. Her sharp historical knowledge, especially in Japanese history, bridges her rapport with Hinomaru and bolsters her managerial contributions.

During Chiba Prefecture’s Inter-High qualifiers, Chizuko documents matches and shares videos to amplify the club’s reach. Her efforts attract schoolwide attention, boosting resources and fan engagement. This initiative sparks tension with Reina Gojo, the reluctant co-manager, who views Chizuko’s proactive approach as a challenge.

Outside sumo, Chizuko paints watercolors and harbors unexpected swiftness despite her quiet demeanor. Post-timeskip, she continues supporting the club at 19, though her exact activities remain undefined. Familial ties and academic prowess subtly shape her character without overt exploration.

Her name, derived from the kanji for "thousand," "crane," and "child," mirrors traditional symbolism. Additional notes highlight her blood type A and strategic social media use, which catalyzes the club’s expansion through documented progress.