Akira Koizumi is a high school student with striking blue hair, red eyes, and a petite frame that belies her forceful personality. She cultivates an air of icy mystery at school, fueling rumors about possible lesbian inclinations or compensated dating with older men. This speculation partly stems from her participation in a circle conducting phone pranks; posing as "Alice," she lured men to public locations for amusement, meticulously avoiding actual sexual encounters.

Deep-seated low self-esteem and a profound distrust of others, particularly men she views as shallow, underlie her aggressive defensiveness. She pushes people away and lives independently, reinforcing her isolation.

Her dynamic with Keisuke Saji ignites when he stumbles upon her "Alice" secret. To ensure his silence, she spends an evening with him, culminating in a sexual encounter where she loses her virginity. This becomes a pivotal moment. Saji's persistent pursuit and authentic affection begin chipping away at her emotional barriers. Though she frequently reacts violently to his overtly perverse actions and publicly denies romantic feelings, genuine affection for him grows. Privately, she acknowledges his sincerity and starts relying on his steadfast support, struggling to express this vulnerability openly.

Across the series, Akira evolves significantly: She learns to lower her defenses, accepting that Saji's devotion is genuine care, not transactional. Friendships with Ryoko and Maki, combined with Saji's influence, help her confront loneliness and self-worth issues, leading her to choose staying in Japan over further isolation. She also possesses a covertly perverse side, occasionally engaging in teasing or sexually suggestive behavior, especially with Saji, though such impulses easily embarrass her.