Yamato (ヤマト - "Yamato") somehow parachuted into the work. His first appearance was in chapter 983, where he saves Luffy from the attack of the Tobiroppo: Ulti and Page One. In short, at first glance, he is referred to as Kaidō's son - apparently the only one, by the way - because he presents himself as male, in other words, a man. I'm sure this is because, from a young age, he liked and admired Oden, his father's enemy, So when "the" interpreter took off her mask and revealed herself as a woman.