Shou Marui captains Aota Academy's girls' volleyball team as their left-front attacker and most skilled offensive player. She embodies leadership with modesty, a down-to-earth nature, affection, athleticism, playfulness, responsibility, and spirited energy. Uniquely among teammates, she instantly warms to coach Ou Motoura, embracing him as their trainer while nurturing an early crush.

Shou shares a sisterly bond with teammate and setter Kumi Marui. She excels at integrating newcomers like Fumie Shiratori and Hitomi Kido, reinforcing team unity during crises such as Motoura’s absence.

In the sequel OVA, Shou accompanies the squad to a hot spring resort training camp before nationals, where rivals orchestrate external threats against the group. Her individual actions, backstory, and character evolution remain consistent with her documented traits and role.