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 had lost the use of her legs, along with some of her memories, allegedly due to a car accident.

In her hero form, she uses guns and sniping rifles for long-range combat and her ribbons serve as appendages for moving around. She also has three familiars, Gyoubudanaki, Aobouzu, and Shiranui. As a result of using her Mankai form, she loses her hearing in her left ear.
Sumi Washio
At the end it is revealed that Mimori was once a hero during elementary school under the adopted name of Sumi Washio. She initially used a bow and arrow before gaining her rifles. The upgrade also gives her a fairy companion called Aobouzu. After losing her legs and memory to the Mankai form, she was returned by Taisha to her original family to eventually serve as a hero once more. The only remaining link to her past is a ribbon given to her by Sonoko, her best friend and fellow hero at the time.