Yuuko Kokonoe  

, 九重 ゆうこ

Yuuko is a third-year student at Yukihiro's school and serves as the chairperson of the staircase club. She has an outgoing personality, was previously part of the track and field team representing the school in hurdle events, but later left to establish the staircase club after being introduced to it by Kengo. Despite her petite stature, she is incredibly fast when running, earning her the nickname "Silent Bullet" (静かなる弾丸, Shizukanaru Dangan).