Yamanami Juubee

He is the father of Masamune and Minaho. Worried about his daughter's feelings for her brother, he sends her abroad to study, but in exchange he must allow her to be assigned as his homeroom teacher.

He is a strict but overly lenient father. He advises Masamune on what to do, but also enjoys teasing him. He is quite busy, and often doesn't come home leaving the two alone for months. However, he worries about the two of them, and acts as an eccentric detective.

He is a complete nuisance to both his children.