Yuuna's best friend and fellow classmate and club member who lives next door to her and often prefers to be called by her family name. Mimori takes pride in her national heritage and is always ready to defend her country and protect its people. She has lost the use of her legs, along with some of her memories, allegedly due to a car accident.

Spoiler

Two years before the main story, Mimori was adopted by the Washio family because of her high aptitude as a Hero Candidate. She went by the name Sumi Washio for the entirety of her time adopted by the Washio family. After her Mankai caused her memory loss, she was promptly returned to the Tougou family and was conveniently relocated by the Taisha as a neighbor to Yuuna.