amato is the son 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 Kozuki 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 become a man and identify as Kaidou's son, with his father and the Beasts Pirates referring to him as such as well.[4]

This path has put Yamato at odds with Kaidou, with much of his life being spent imprisoned on Onigashima. Yamato befriended Portgas D. Ace during his visit to Wano Country, and after learning of Ace's death waited for the arrival of his sworn brother, Monkey D. Luffy.[9] Initially desiring to join Luffy's crew,[10] Yamato ultimately decided to remain behind in Wano to help protect it from outside forces, though he still intends to join them in the future.[11] Yamato greatly admires the legendary samurai Kozuki Oden to the point of even proclaiming to carry his identity. Yamato has self-identified as Oden on multiple occasions and has even emulated his gender, proclaiming to be the son of Kaidou due to Oden being a man.[4] Although initially carrying doubts as to how to present as Oden,[14] Yamato has steadily expressed a straightforward attitude regarding this identity as time has gone on, even proclaiming this as such to Oden's son Momonosuke, to the boy's horror.[15] Although having wholeheartedly embraced this identity, Yamato retains his original persona, referring to Yamato as his "other name".[2] Yamato does not seem to like being misnamed, having quickly corrected Luffy when given a nickname.[16]

Having read of the great exploits documented by Oden in his logbook, which he considers his "bible",[4] Yamato dreams of leaving Wano Country's confines and setting out to sea with the Straw Hat Pirates, much like Oden did with the Whitebeard and Roger Pirates decades before.[9] Yamato also wishes to fulfill the goals that Oden had, namely opening Wano'