Naoshi Haruki  

, 陽日 直獅

Haruki Naoshima, 24 years old, is Tsukiko's homeroom teacher at high school. He enjoys working with Iku as his student teacher because it reminds him of the youthful energy that he missed out on during his own high school days. When a student transfers to the class, Naoshima feels guilty for not being able to help and believes he has failed as a teacher.