Aki generally appeared to be a very stoic person. He acted mature and sometimes blunt to the point of rudeness when he was with his fellow Devil Hunters, but he was actually fairly softhearted. He had a tendency to get attached to others easily, and hated to see people get hurt, especially his close friends especially one of his partner who died because of devil when he heard that his ex-partner have an a younger sister who sacrifices her life for her older brother in hospital