Kouichirou Ryuuzaki

Reina's father. He teaches Math at Tanaka and Reina's school "triple handicapped" with stage fright, anxiety neurosis, and anthropophobia. People mistake his taciturn behavior and murderous glare as him being angry at them, when in reality Kouichirou is the one who is scared of interacting with people. Kouichirou only became a math teacher because he liked to solve math problems and take an active part in people's lives. He is a typical father; seeing his daughter as a perfect little princess and calls her 'Rei' and 'sweetie'. He gets along fine with Tanaka viewing him as a helpful and trustworthy boy who is not afraid of him. He and his wife Ran, whom he met in high school, are still deeply in love with each other. When he was entering high school, he asked his younger brother how to change his image so that he would never be picked on. His younger brother helped him dye his hair blonde which is the typical telltale sign of a delinquent. The plan was a success: Everyone avoided him - mostly because they were afraid of his appearance. Ran, at the time a yankee and leader of her own gang, fell in love with him at first sight, and was the first person to confront and talk to Koichirou. Koichirou, pleased and surprised to find a person whom he could call a friend, eventually falls in love with her. [Summary from Wikipedia]