Occupation Biology researcher Shuu Hagiwara is a teacher and the ex-boyfriend of Hina Tachibana due to fact that Shuu is married, therefore his relationship with Hina for the last two years is an illicit affair and he also seems to have a good friendship with Reiji Kiriya. Shuu is a friendly and thoughtful person who has a playful side to him, owing to his puppets and ventriloquism skills. According to Reiji Kiriya, Shuu was constantly sad and fatigued with having to deal with his wife. Because of his unhappy marriage, Shu was ready to take risks with his affair with Hina Tachibana. Unfortunately, he has been indecisive on ending the marriage for some time. When he noticed that Natsuo Fujii was in love with her as well, Shuu was a bit vexed, but nonetheless let Hina choose between him or Natsuo.