|Appearance||Period 14: From The Land Of Mirrors|
Kumi has dark colored hair at shoulder length with curled ends. Her thin, curled bangs are tented at her forehead. She has slightly curved eyes and a beauty mark by the lower corner of her mouth. She wears a school uniform with the blazer around her waist.
Kumi is a playful girl who enjoys teasing her friends and playing tricks on Miyuki, due to how easily scared she is.
Kumi began to tell Miyuki about the legend surrounding the Land of Mirrors and teases how easily scared she is until a boy bumps into her. She introduces him as Araya and remarks on how good looking he is, but he's also really weird. She got annoyed after Miyuki suddenly tapped the mirror where she had been standing, and after scolding her for doing this she suggested they take off and tried to calm the suddenly worried Miyuki.
The following day, she shows up with an injury and startles Miyuki when she points out the injury was because of her. She insists its nothing, observant of how worried Miyuki is when after class, she calls Nako over and they leave to go and check out the mirror again. By the time Miyuki finds them she is horrified to see them acting strange again. Kumi suggests they return to class but after Miyuki claims she neess the restroom she and Nako go on ahead.
Eventually, by the time Miyuki takes a swing at the mirror Kumi calls for her with Nako. They quickly apologize and explain how they were only playing a joke on her. They convinced their whole class to join them but they didn't mean to make it go this far, and they had intended on telling her until she ran from the Resource Room. Miyuki is entirely confused and she points out how Kumi's mole shifted sides, and how she gained a sudden injury- but Kumi explains that this is due to her using a marker and covering up her actual beauty mark; and the injury was purely coincidental. While everyone expresses relief, Miyuki suddenly notices that Kumi's injury looked like a crack as several more begin to form on her and her friends, and one by one they suddenly begin to shatter and bust apart until all that remains is an entirely broken mirror.
Miyuki and Kumi are then shown standing before the busted mirror with a baseball bat. Kumi criticizes her for doing this and she is sure their teachers will be angry when they find out, but Miyuki argues that Kumi was the one who told her to do this and shouldn't get all the blame. While joining their friends, Kumi brings up the story about the land of mirrors.