Aki generally appeared to be a very stoic person. He acted mature and sometimes blunt to the point of rudeness when he is with his fellow Devil Hunters, but he was actually fairly softhearted. He doesn't like people who do not take their job seriously. Aki is ruthless, stating that he always makes sure the Devils he kills suffer. His air of cold detachment was a facade, and he had been seen to cry over the death of his comrades. Aki is afraid to lose those he truly cares about.