Sonoko Nogi

園子乃木, そのっち, Sonocchi
Nogi Sonoko is one of the three main characters of the light novel Washio Sumi is a Hero. At the time of the story taking place shes an elementary school 6thyear student chosen by Taisha to fight Vertexes as a Hero along with Minowa Gin and Washio Sumi. Source: Yuki Yuna is a Hero Wiki