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. Aki has an undeniably strong hatred for devils, fiends and hybrid alike, and when killing them, he has no second thought. He sees them as pests, and holds a grudge against them due to the death of his family caused by the Gun Devil.