Amakusa Tsubaki

A third-year student who is the former president of the string orchestra club. She is in charge of the contrabass, though she rarely shows up to club activities. Tsubaki is a mysterious girl who rarely shows any emotions on her face, but she also has a mischievous side to her.

She is actually Mai and Nao's aunt; their deceased mother's much younger sister. However, she doesn't take it kindly if you call her an aunt.