|Appearance||Period 43: Marionette's Lover|
Riri is an average looking or "plain" teenage girl with big, innocent eyes and short dark-colored hair that slightly frames her face.
Junko appears to be an uneasy and shy girl who keeps to herself and is fairly quiet. She admires her friend Lala, but having also known her boyfriend for so long, she feels heavy remorse for having developed feelings for him.
As gentle as she appears, she is shown at the ending to be manipulative and like Lala, cares greatly about her own happiness. But she adores Aki and is very happy to be with him. It is implied she is a yandere.
With no interest in the marionette someone gave her for her birthday, Lala tossed it in Junko's direction and suggested she use it as she was the only girl in their group without a boyfriend. She was later shocked to discover an intimate text from Junko sent to Aki, asking him what he liked as a side dish because of the bento she was preparing for him.
Lala could barely believe that Aki and Junko could ever have some sort of relationship, but throughout the day when she begins seeing proof of her worries, she takes the puppet back and begins using it in order to get revenge. First she has Aki ignore Junko, and later she lovingly dotes on Aki until noticing Junko storm out of the classroom. But as she begins to get consumed with thoughts of revenge, she is approached by Junko later who asks to speak to her. Lala agrees before confronting her with what she knows, and in tears Junko confesses to what she suspects. She admits to having had feelings for him since they were first years, and she often gave him advice whenever he would stress out. She knew she had to leave him alone but she couldn't help it, and they are very happy.
She asks Lala to forgive her, but after Lala begins to briskly respond they are joined by Aki, who confirms Lala's fears. They leave the room after he coldly tells her off for only caring about herself and how he refuses to follow her commands any longer.
After Lala's incident, Junko is shown observing a page on the puppet and she muses that Lala ended up doing what she expected her to, and now she can finally be happy with their relationship out in the open. Her odd behavior causes Aki concern as she latches onto his arm, and they take off for home.
- She greatly resembles Riri Itou.