A divorced single mother who works at a lunchbox shop and previously as a club hostess. She is portrayed as a pretty and personable woman with a narrow focus primarily on her and her daughter's problems.

Yasuko's abusive ex-husband who is depicted as a cruel and selfish character. His past as a successful businessman ended after he was caught embezzling funds.

A diligent and observant police detective with the Tokyo Police known for his intelligence and intuition. He shares a long-standing friendship with Yukawa and seeks the truth in difficult cases.

A physicist at Imperial University known for his attractive appearance and analytical skills. He shares close friendships with Kusanagi and Ishigami, and his methods and demeanor are reminiscent of Sherlock Holmes.