Naoto is tall and athletically-built. He has short, gray hair and dark gray eyes. He has tanned skin, and usually wears casual clothing.
Naoto is very mature and gentle. He is reserved and believes in not bothering people with his personal issues. He used to have anger problems as a child, but he learned to use them positively as he grew up, and only falls back on them when Diana curses him.
Naoto is a high school student working part-time in a conveyor-belt sushi restaurant.
In the past, Naoto was bullied due to being weak. After the bullies killed his pet goldfish, his grandmother comforted him and said that he must transform his feelings into strength to defend others.