Aya lives and works at the Arisugawa bathhouse, a traditional public bath run by her family. As the eldest sibling, she takes on a supportive role, helping maintain the business alongside Kaname. While she isn’t particularly focused on deep intellectual pursuits, Aya is known for her physical prowess, cheerful personality, and overall reliability.

She grew up in the same neighborhood as Nasa Yuzaki and watched him grow into a local genius, which left a strong impression on her. Even though their personalities differ, Aya has always supported Nasa and viewed him with admiration and curiosity.

Aya is a tall and athletic young woman with long dark-blue hair, often tied back in a ponytail, and dark brown or purplish eyes. She typically wears casual clothing or her bathhouse work uniform, appearing relaxed and confident. Her build and presence reflect her sporty nature, contrasting with her younger sister’s petite frame.

Though not overly concerned with fashion or appearance, Aya has a natural charm and often comes off as approachable and easy to talk to. Her body language is expressive, and she tends to smile frequently, making her a comforting presence in the story.

Aya is easygoing, upbeat, and sometimes a bit slow on the uptake. While not the most perceptive or intellectual, she has a strong moral compass and a kind heart. Her relaxed nature makes her popular with customers at the bathhouse, and she gets along well with most people she meets.

She’s also quite physically gifted, often playing sports or demonstrating surprising strength, which complements her work ethic in helping around the bathhouse. Aya is naturally supportive, showing pride in Nasa’s accomplishments and treating Tsukasa with warmth and curiosity.

She tends to be oblivious to subtle social cues, which sometimes makes her miss the deeper implications of what’s happening around her. However, her simplicity is part of her charm she brings light-hearted energy to every scene she’s in.

• Familiar Face from the Past
  Aya first appears as one of the bathhouse workers who is pleasantly surprised to learn that Nasa, whom she hasn’t seen in a while, has gotten married. While her younger sister Kaname reacts with sarcasm and curiosity, Aya’s response is pure joy and admiration. She expresses genuine support for Nasa’s sudden marriage and treats Tsukasa kindly from the start.

• Unintentional Insight
  Though not deeply involved in the mystery surrounding Tsukasa, Aya offers small moments of unintentional insight. Her comment, “This girl made me think of Nasa-kun for some reason,” subtly reinforces the thematic connection between Nasa and Tsukasa two characters who are more alike than they realize. Aya, without fully understanding it, perceives that same depth in Tsukasa that she sees in Nasa.

• Comedic Balance
  Aya contributes to the series’ slice-of-life and comedic tone. Her interactions with Kaname, who often bosses her around despite being younger, add a humorous sibling dynamic. While Kaname takes the role of the clever observer, Aya is the lovable muscle slightly clueless but always well-meaning.