Satoko is a younger classmate in Keiichi's school. She has a distinctive style of speech, ending all of her sentences with ~wa, and is known for her boastful laugh. In spite of her young age, she seems to have an impressive arm strength and is quite clever in setting up traps, and likes to practice on Keiichi. Although her personality is quite energetic and mischievous during the events of the games, Satoko's past was full of trauma; her parents died in an accident, she was abused by her foster parents, and her beloved brother Satoshi disappeared. However, in Matsuribayashi-hen, Irie suggested she killed her parents, as she had a bad relationship with them and felt threatened, and so to her it was an act of self-defense.