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, most 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. After killing a mafia organization with his own hands, Ryoma considers himself a killer, the kind of person other people should not get close to. While generally not appearing very aggressive, he is apparently willing to harm and even kill people if he believes they deserve it, and he occasionally gives others a very piercing look as a warning.