Born October 10, 1997. A student at the police academy and Kai's roommate. The complete opposite of Kai, he is a physical type who rushes in before thinking. Kai calls him "Jiro-chan." He is generally poor at academics. On the other hand, he is an all-around athlete and a powerhouse capable of defeating even experienced martial artists. He often puts himself in danger by acting without thinking or confuses others with insensitive remarks, but he has an innocent and friendly personality. Like Kai, he has a weakness for beautiful women, and when it comes to romance, his brain works faster than Kai's. His older brother Taro, who also aimed to be a police officer, died in an accident just before entering the academy a year ago; Jiro decided to become a cop to carry on his late brother's will. Although he can be a bit dim-witted, he possesses a kindness that makes him unable to ignore people in trouble, just like Kai. Because of this, he frequently gets caught up in incidents alongside Kai.

Born November 30, 1995. A student at the police academy and an intellectual type who carefully plans things out before acting. Jiro calls him "Kai-kun." He attended an all-boys high school. After graduating from university, he joined a private company as a new recruit but quit because he couldn't keep up with the excellence of those around him. After working part-time jobs, he remembered his childhood dream of "wanting to be a hero" and resolved to become a police officer (the age limit is 30). He is good at studying and has excellent grades at the academy. He also has sharp intuition. Furthermore, he is skilled in martial arts, holding a 3rd-dan rank in Kendo, yet he was no match for the beginner Jiro. Although he is inexperienced in romance, he seems to have a weakness for beautiful women. While he may seem unapproachable and overly serious, he has a kind heart and cannot leave someone in trouble alone. As a result, he often gets involved in incidents, and his glasses are broken every time. He frequently suffers injuries, such as spraining his ankle during training or throwing out his back. At first, he was bewildered and troubled by Jiro's insensitive and reckless behavior, but their bond strengthened after Jiro helped him when he sprained his ankle during training.