Mafuyu was adopted by Tomo's father and decided to protect Tomo to repay her father for adopting her. Mafuyu and Tomo have been friends since childhood because of this, Mafuyu is very protective of Tomo and won't let anyone harm her, verbally or physically. Tomo loves Mafuyu dearly, and wishes for her to be happy. Also, she doesn't want to be a burden to her. Despite their smaller size, Tomo has a habit of playing with Mafuyu.