A Japanese male, 24 years old. He has black hair, tanned skin, and a deep voice. He is incredibly handsome. His personality can be aegyo-filled at times, but he is terrifying when expressionless. When he smiles, he looks like a cat. He is 175.8cm tall with a slender build and large hands. He is a police officer in Violent Crimes Unit 2. He broke up with Yushi three years ago, and they are now in a mutual relationship of hatred. Riku prefers to solve cases using his brain rather than his body, so he frequently clashes with Yushi, who is in the Gang Crimes Unit and tends to act before thinking.