Naoshi represents the Leo. He is Tsukiko Yahisa's homeroom teacher and the advisor for the archery club. Despite being the second oldest of the main characters, he is quite short (the shortest of all the main characters) and is often teased about it. He is hotheaded, energetic, and enjoys the "youth" part of high school. Because of that, a lot of students can't take him seriously and often play pranks on him. If Naoshi falls for the prank, they get to eat parts of his lunch, else they have to buy him food. He gets along very well with his students and is sometimes invited to play soccer. He is protective of his students, especially Tsukiko, since she is the only girl in the whole school. While not with his students, Naoshi is often in the Infirmary talking with Kotarou Hoshizuki and Iku Mizushima. Kotarou specifically asked him to take in Iku as the student teacher of his class. He likes to drink and is skilled with computers.
During his highschool life, he acted very differently. He was generally serious and spent much of his time studying. Naoshi's best friend, Hiroki, got him to enjoy high school life, but Hiroki was hit by a car saving the girl he liked, falling into a deep coma. Because of this, Naoshi is afraid of love and hasn't fallen in love until he met Tsukiko.
Naoshi has orange hair and yellow-coloured eyes. He wears a hoodless, multi-coloured jacket over a red shirt. He also wears saggy blue-black jeans.