Yuki Yuna is a Hero S2: The Washio Sumi Chapter
Two years before "Yuki Yuna is a Hero." Sumi Washio is only in 6th grade, but she's a hero who was chosen by Shinjyu to save the world. Sumi fulfills her role while cherishing her precious regular life with her classmates, Sonoko Nogi and Gin Minowa.