Arisa Takamizawa attends Sakuragaoka High School alongside classmates Hina Setoguchi and Kotaro Enomoto. Noticing Hina’s budding attraction to Koyuki Ayase, she deliberately interferes to create distance between them, aiming to steer Hina toward Kotaro. Driven by a desire to clarify Hina’s romantic intentions, her meddling inadvertently escalates tensions, causing Hina to perceive her as a rival.

Her relationship with Hina shifts during a fast-food outing when Arisa grows uneasy after encountering a former classmate who transferred schools. Hina diffuses the discomfort by sharing half her pie, sparking a grateful connection that begins to mend their friction. Later, Arisa publicly defends Hina during a strained café conversation, an act that solidifies their growing friendship.

Arisa clashes persistently with Ken Shibasaki, dismissing his lighthearted demeanor as unserious. She openly critiques his behavior in group settings, reinforcing her straightforward, principled nature. Beyond these conflicts, she actively nudges Kotaro to pursue Hina following Koyuki’s rejection, emphasizing her vested interest in their romantic outcome.

A montage depicting classmates’ activities briefly references her part-time role as a shrine maiden. While her family history and personal past remain unaddressed, her actions consistently reflect pragmatism, loyalty to friends, and a readiness to confront those whose actions clash with her values.