真澄 あい

Her name "Ai" is written as "哀", meaning sadness, sorrow, and pity.

A girl who calls herself a "sinner" who came to the small village of Tamasato to repent her sins. Upon finding out about Yuuto’s loneliness, Ai confided that she was abandoned by her parents. Gradually, they started dating, but, due to circumstances, rapidly broke up.