Aki generally appears to be a very stoic person. He acts mature and sometimes blunt to the point of rudeness when he’s with his fellow Devil Hunters, but he was actually fairly softhearted. He has a tendency to get attached to others easily, and hates to see people get hurt, especially his close friends.

He lost his friend Himeno in a mission against some devils. He lost his family to the gun devil when he was only a child.

He has severe PTSD and depression. He has blue eyes and black hair