Kai Yukino

Yukino is the newest teacher at Hoozuki Island school, being in charge of health and physical education. She is a 2-dan in kendo. She was neglected by her parents, and due to her friend Mai being incarcerated for child abuse, Yukino herself decides to become a teacher to understand the relationship between children and adults. She wants to help students in any way, but they are distrusting of her along with the other adults.

(Source: Wikipedia, edited)