Nami Hayase captains Hikawa Junior High's girls' volleyball team as its top player, excelling as a central defender and receiver. She begins cold, arrogant, and dismissive of new teammates, especially the protagonist, embodying an Alpha Bitch persona with a clique of followers and rejecting admirers. Her rivalry extends beyond volleyball into a romantic competition for the boys' team captain's attention.

Her dynamic with the abusive coach, Daimon, is complex. Initially favored, she endures his violent training methods, including repeated physical punishment. A pivotal moment occurs when she defends a teammate against Daimon's brutality, revealing underlying loyalty. Repeated defeats and growing teammate isolation trigger a Jerkass Realization. This leads to significant development: a Heel–Face Turn transforms her from antagonist into the protagonist's closest friend and confidante, a friendship enduring even on opposing professional teams.

Transitioning to a Daimon-coached professional team, she excels as a top receiver and server, renowned for her "swallow's flight" serve. Daimon eventually sidelines her for newer players, diminishing her prominence. During national team selections for the 1988 Seoul Olympics, she is assigned to National Team B, contributing as a reliable defender. She navigates internal conflicts, including clashes with an abrasive teammate, maintaining a steady focus on team cohesion.

In the 2008 sequel *New Attacker You!*, set years later in China, she appears as a recruited player for the Dragon Ladies. Her involvement is minimal, with no substantive development or background expansion. The narrative shifts to new characters, leaving her a peripheral figure without further exploration of her journey or relationships.