He is a second-year student at Mihama Academy who is known as "Ace number ", receiving this name after his master, a former assassin for a Japanese government agency and black ops employed by Ichigaya, passed away. Growing tired of his aimless existence, he desires a normal school life. He is characterized as cool, philosophical, and minimalist, maintaining a realistic outlook on life.
Though he occasionally relies on orthodox military methods, Yuuji considers himself cowardly and prefers to plan and scout before taking action. He disguises himself as an exchange student from Canada at his new school and is a physically fit young man.
Yuuji is a good-looking and somewhat intimidating young man with short black hair and sharp black eyes. Due to a lifetime of physical training, Yuuji is athletic, although his body is covered with scars from his career as an operative.
Yuuji is a cold and reserved guy who is inured to a lifetime of violence. He usually doesn't care about people's opinion and is known for his sardonic humor. Yuuji admits that he isn't a brave person, and often prepares contingencies prior to engaging the enemy.
He likes to read books, a habit that was ingrained into him by Kazuki Kazami and Asako Kusakabe. This is also partially to do with the "safety pin" Asako placed on him to keep him from killing.
