Yuki Yuna is a Hero: The Washio Sumi Chapter

Era of the Gods, year 298, two years before "Yuki Yuna is a Hero." Sumi Washio(6th grade) who was chosen by the Shinjyu, is a hero who protects the world alongside her classmates, Sonoko Nogi and Gin Minowa. It seems like Sonoko and Gin are trouble-makers because they could be idiotic or too energetic. Sumi is excited that she should lead the other two, but... (Source: Amazon)