Hirouin is the principal of Komatane Junior High School and the father of Hirouin Takane. As principal, he's a gentle and friendly person but, when he senses wrongdoing, he rushes out, puts on one of several silly costumes, and becomes the Secret Hero, ally of justice. Hirouin doesn't think anyone knows he's the secret hero but his huge, spherical head generally gives him away. Everyone except Misaki knows Hirouin is the Secret Hero.
Principal Hirouin knows about Futaba's secret, having had previous experience with Futaba's sister Futana, and often tries to help Futaba keep that secret.The name Hirouin [ΘμΟ°±‘] literally means `scarlet watchtower temple'.