Ryoma is a hard-boiled dandy character. Though he looks like a child, it's been said that his life experience would put an adult to shame. He has a coolness that common high school students don't have, heightened by his very deep, mature voice. He is the calmest, composed, and an unperturbed person in the Killing Game. He isn't shaken by murders nor even if he is personally harmed. He often mentions how he refuses to do something "uncool" and doesn't want to show his softer side.

Voice reference: https://www.youtube.com/watch?v=PhyacTkJhvU