Yamato is the daughter of Kaidou. Born as Kaidou's daughter and groomed from a young age to be his heir, Yamato instead developed a profound admiration for the legendary samurai Kouzuki Oden. After Oden's death, Yamato decided to become like him, impersonating him and adopting his mannerisms. As a result of this desire to emulate Oden, Yamato decided to disguise as man and identify as Kaidou's son, with her father and the Beasts Pirates referring to her as such as well.