The best friend of Utsuya Madoka since the second year of middle school. Nitogi cherishes Utsuya, having feelings for her; however, she will not confess as she doesn't want to risk losing Utsuya as a friend. During her middle school years, she accidentally caused a fire that ended Utsuya's mother's life. Now, she does all she can to protect Utsuya, not wanting her to be hurt by anyone.
In order to protect Utsuya, Nitogi murders anyone who has the potential to hurt Utsuya.