An 8-year-old boy (1st grade) of mixed race, though he doesn't know his specific heritage. He frequently gets into fights because other children pick on him for his appearance. He harbors a strong dislike for those who bully him for being mixed-race. His personality is a bit prickly and he has a 'tsundere' side, but he is said to become quite kind once he opens up. His dream is to become a police officer. He decided on this goal because a doctor he liked once told him, "Our little Rei would make a great Public Security officer." (Past) One day, while receiving treatment from a doctor named Elena Miyano, Rei fell in love at first sight. Since then, he has adored her and would visit her clinic whenever he was injured. It's even said he would sometimes get hurt on purpose just to see her. However, the doctor suddenly disappeared one day, and he hasn't been able to see her since.