Jotaro is the son of Usagi and Mariko, Usagi's ex-girlfriend. However, Mariko asked Usagi to promise that he would not share this fact with Jotaro for the fear that it could break the bond between Jotaro and Kenichi, his step father.

Like Usagi, Jotaro is naturally skilled with the sword. Following Usagi's advice, Jotaro sought the instruction of Katsuichi sensei. Katsuichi has observed that once Jotaro develops self-discipline, Jotaro may very well become his finest student.