Koushi is a handsome, intelligent, yet physically weak seventeen-year-old high school student who is the son of Unken Inuzuka, a martial arts master and member of one of the twelve Zodiac Master families of Japan. His family is associated with the dog of the Chinese zodiac. However, against his father's wishes, he wants nothing to do with martial arts. He has avoided training ever since being terrorized by bullies at a young age, which initially caused him to freeze every time that he sees violence. Due to this, he wants to someday become a prosecutor so that he will be able to punish crimes effectively. As such, he is constantly seen reading books on laws and codes that govern Japan. Whenever he finds himself about to get into a fight, he recites several laws that his attacker is about to break as well as the consequences, in an attempt to dissuade the attacker, which is not always effective. He seems to believe that martial arts do not have any realistically applicable power and the rule of law can be used as a weapon against enemies.