A calm and intelligent boy who lives alone. Like Imari, Shirou is seen as somewhat odd. He intends to become a detective like Kiyotaka and apparently does not worry about the consequences of pursuing this path. His obsession with Yukine Amanae and Kiyotaka stems from an incident where he was kidnapped by murderer with long black hair (like Yukine). Helpless and unable to act, Shirou watched as Kiyotaka arrived and save him by telling the murderer that she could die and the woman committed suicide. Shirou's desire to reach Kiyotaka is to see if Kiyotaka's decision was right, but he feels the only way to achieve this is to reach the detective's level. After dropping out of school, he dates Yukine Amanae after she reveals a mutual interest in Kiyotaka. When Yukine's role as a serial killer is discovered, he turns her into the police. However, he continues to investigate Yukine with Ryoko in hopes of saving Yukine.