Ai Nishimura is a high school student and supporting character who appears as a classmate of the main protagonists, Yuuki Hase and Kaori Fujimiya. She is best known as a close friend of Saki Yamagishi, another key figure in their social circle. Her birthday is on November 9th.

In terms of personality, Ai is portrayed as a good coordinator and social facilitator. She demonstrates a natural ability to read the dynamics of the people around her and takes an active interest in the relationships forming within her class. Along with her friend Makiko Kujo, Ai is shown to be very interested in the developing bond between Yuuki and Kaori, observing their interactions with curiosity and support.

Her primary role in the story is as a supportive friend and classmate. While not a central figure in the main conflict regarding Kaori's memory loss, she contributes to the warm and inclusive atmosphere of the friend group. Her main connection is to Saki Yamagishi, whom she befriends and spends time with. Through this relationship, she becomes part of the larger circle that includes Yuuki and Kaori, often participating in group activities and lunches.

Ai does not undergo a significant personal development arc, as her function is to provide steady, reliable support to the main characters and to help reinforce the themes of friendship and connection that are central to the story. Her notable ability lies in her social coordination, helping to keep the group dynamic smooth and ensuring that everyone, particularly the more timid or socially anxious characters, feels included.