Hiroshi Mishimaki coaches the Shiratama Middle School soft tennis team, where players affectionately call him "Mishi." As a former national champion in soft tennis, his approach to coaching is notably relaxed, occasionally appearing lazy. He consumes alcohol, evidenced by an extensive drinking session with the vice principal. Yet beneath this demeanor lies sincere dedication: Mishimaki genuinely cares for each team member and strongly desires their success. He harbors a significant fear of supernatural phenomena, reacting to Yayoi Hiragishi's spirit interactions by fleeing to churches or Shinto shrines for refuge. Additionally, he is the cousin of Shiki Nishioka, the team's former captain who now attends high school.