Arashiko Yuno is a main character in the story, a high school student and classmate of Tarō Sado. She is also a member of the Second Volunteer Club, an organization where students work to confront their personal problems. Her own challenge is a severe case of androphobia, the fear of men, which deeply influences nearly every aspect of her life. This condition stems from a traumatic incident during her junior high years, when she was forced into a relationship with an older student named Yoshioka. After she scratched his face when he tried to force a kiss on her, he responded by violently assaulting her. This event instilled in her a subconscious, defensive belief that she must strike a man before he can strike her.

As a result of this trauma, Arashiko is generally shy, insecure, and withdrawn, often appearing quiet and distant to those who do not know her. Her phobia makes ordinary social interactions with male classmates nearly impossible, and she reacts with instinctive, brutal violence towards any boy who accidentally touches her. This reaction is not malicious but a reflexive, uncontrollable defense mechanism. Despite her frail appearance, she displays explosive, superhuman strength when she is on the attack, fueled by her fear. However, away from her triggers, she has a gentler side. She loves animals, with a particular fondness for visiting the zoo, a place that holds happy memories for her from a time when her family was more harmonious.

Arashiko’s most significant and complicated relationship is with Tarō Sado. Ironically, it was her phobia that first connected them years earlier. When he tried to confess his feelings to her in junior high, her fearful reaction caused her to strike him, an event that awakened Tarō's latent masochistic nature. Now in high school, despite her fear, she has developed a genuine crush on him. She finds herself caught between her desire for closeness and her phobia, leading to comedic yet heartfelt situations where she will inadvertently hit him, apologize profusely, and then try again. Her role in the Second Volunteer Club is central to her motivation, as she actively seeks to cure her androphobia with the help of her friends, allowing her to live a more normal life and pursue her feelings for Tarō.

Within the club, she is close to the other female members, including Mio Isurugi and the club advisor Michiru Onigawara, who provide her with support and encouragement. Her development is a slow but progressive journey to overcome her past. She pushes her own boundaries, at one point training intensely to become more assertive and even challenging Mio to a competition for a date with Tarō. In later developments, her courage allows her to confess her feelings, and she is able to begin a romantic relationship with Tarō, even though her androphobia remains an obstacle she must continue to work through. Her character is defined by this struggle, embodying both the fragility of trauma and a resilient will to find happiness and human connection.