小野瀬 敦司

A prodigious teacher having become the headmaster of St. Claus at a young age. Atsushi is a hardworker who has put his everything into all he has achieved in his life.

He doesn't have a boastful or prideful personality, but instead, is mild-mannered and pacifistic. His students included, Atsushi is kind and polite to anybody. One of the reasons why he's popular amongst the students is because he tries to view things from their perspective rather than from "up above everyone else".

However, the number one reason he is popular appears to be because his calm demeanour and politeness exerts the alluring aura of a mature man, as well as his looks that keep his age a mystery.