Kazuichi "Pin" Arai

Birthday is July 25th. Blood type B.

A teacher at Kitahoro High School. Teaches physical education and is the baseball team coach. Single. Initially, he was the assistant homeroom teacher for Sawako's class, but became the homeroom teacher after the previous teacher, Mr. Arai, retired at the end of the first semester of freshman year. He continued as Sawako's homeroom teacher during their sophomore and junior years.

Nickname is "Pin." He is from the same youth baseball team coached by Kazehaya's father and has known Kazehaya, Ryu, and Chizuru since they were young. He was a notable player from Kitahoro High School's baseball team, even getting scouted by a professional baseball team, but chose to become a teacher because he wanted to coach high school baseball (as it is common in the area for teachers to be coaches).

He is unaware of it, but he has a sixth sense.

Confident in his ways, he often exhibits unconventional behavior not typical of an educator, but he also provides reliable advice to students struggling with love or career choices.

He particularly had many interactions and consultations with Ayane. Close to graduation, Ayane confessed her feelings to him, but he turned her down, encouraging her to focus on her future.

His motto is "I am the only master of my fate."