Aki generally appeares to be a very stoic person. He acts mature and sometimes blunt to the point of rudeness when he is with his fellow Devil Hunters, but he is actually fairly softhearted. He has a tendency to get attached to others easily, and hates to see people get hurt, especially his close friends. Unlike many of his associates, he is described by Himeno as being a "normal person", in the sense that he still grieves for those lost and has not become jaded enough to close his feelings off. Despite this, he is very determined and his primary motivation for killing the Gun Devil is revenge for his family. He is, however, entirely willing to put his own life on the line to save other people despite his own fear of death and even at risk to his ultimate goal.