Yamato is the daughter of Kaido. She is otherwise widely referred to as his son due to often presenting herself as a man as a result of her profound admiration for the legendary samurai Kozuki Oden and her aspiration to emulate him.
Yamato is a tall woman, though not nearly as tall as her father, being slightly over twice Luffy's height. She has long, light-colored hair that is tied into a ponytail at the back, which turns darker further down and ends in rectangular locks similar to her father's, and she has a pair of horns atop her head that start out light-colored but then turn darker. She has large eyes with prominent eyelashes, and wears hoop earrings on her ears. Much like Oden, Yamato wears a large nio-daisuki on her back. She wears a pair of hakama pants and sandals, and had exploding cuffs around her wrists with a short chain attached to each of them until Luffy removed them.
When in disguise, she wears a hannya mask over her face, which has a wig of an extremely long and wild mane attached to the top and a long goatee attached to the bottom. She wears a multi-colored kimono with a diamond-shaped design on both sides of her chest; she wears the kimono traditionally when disguised in order to hide her chest, but when she revealed herself to Luffy she ripped off the sleeves and made the garment more form-fitting. 
Yamato holds immense admiration for the legendary samurai Kozuki Oden, emulating every aspect of him, including his appearance, goals, and even his gender, reasoning that, since Oden was a man, she herself chose to become a man. Yamato wishes to fulfill Oden's dream of reopening the borders of Wano Country. This attachment to Oden puts Yamato at odds with her father Kaido, who is an enemy of Oden and his family. Although Yamato and Kaido are not indicated to be enemies, Yamato has acted against her father and his crew to achieve her goals, such as attacking Ulti in order to take Monkey D. Luffy from her, and wishing to work with Luffy, another enemy of her father, to achieve Oden's goal.
Yamato and her father Kaido have a strained relationship, as Yamato idolizes Kaido's enemy Kozuki Oden. When Yamato told Kaido she wanted to be Oden, Kaido responded by beating her. However, Yamato has emulated Oden for the past 20 years to the point of even presenting as a man like him, and although Kaido disapproves of her idolizing him, he does refer to Yamato as his son. Kaido does not seem to be aware that Yamato wishes to fulfill Oden's dream of opening Wano's borders, a cause which he is opposed to. Kaido has been cruel to Yamato as he beat her numerous times since her childhood and kept her imprisoned on Onigashima since she was eight years old. He even put explosive handcuffs on her to keep her from leaving. After being freed of her handcuffs, which contained much more explosives than normal, Yamato decided to disown him as Kaido was actually willing to kill her. Kaido's overall view of Yamato is unknown; he has called her an "idiot", though wishes to have her participate in his party during the Fire Festival and later have her replace Orochi as shogun, which unknown to him, is something that Yamato has flatly rejected upon hearing his speech that was broadcast across Onigashima.
Monkey D. Luffy
It appears that Yamato has a great interest in Monkey D. Luffy as she waited for him to arrive at Onigashima and saved him from her father's crew. She apparently trusts him enough to request his help in achieving Oden's dream of opening Wano's borders. Luffy was shocked by her true gender and that she knew Ace. During their conversation, Yamato told Luffy of her desire to leave Wano with his crew. After hearing about how Kaido kept Yamato imprisoned by putting explosive handcuffs on her, Luffy removed her handcuffs. Luffy refers to Yamato by the nickname "Yama-o" (ヤマ男?). Yamato appears to dislike this nickname, as she corrected Luffy with her actual name.
Portgas D. Ace
Yamato mentioned that she and Ace met before. She seems to respect him, as she fondly stated that Luffy reminds her of Ace. She later stated she tried to sail out of Wano with Ace but her father kept her prisoner.
Abilities and Powers
Yamato possesses monstrous strength resembling her father's, being capable of wielding a large and heavy kanabo and using it to defeat Ulti, an Ancient Zoan user and one of the Tobiroppo, with just one blow. She was able to physically match Luffy's strength with relative ease, even when the pirate increased his strength exponentially with Gear Second and Gear Third. Yamato countered a punch from Luffy with her foot, resulting in a powerful collision that destroyed much of the surrounding wall and ceiling and blew back the Beasts Pirates around them. Due to her large size, she is capable of easily picking up the average-sized Luffy and holding him with just one arm while running.
Yamato is quite fast, being able to lunge forward with blinding speed to attack her targets as well as outrun members of the Beasts Pirates chasing after her. She was also able to completely elude the pirates around her in the aftermath of her clash with Luffy and take him to the attic without anyone seeing them.
Yamato wields a giant kanabo club much like her father, though her kanabo is studded and more slender, while Kaido's is spiked and a bit thicker. In addition to the kanabo being a powerful blunt weapon, Yamato has masterful technique with it, being capable of moving it to counter Luffy's rapid attacks with little effort.
- Raimei Hakke (雷鳴八卦 Raimei Hakke?, literally meaning "Thunderclap Eight Trigrams"): A technique used by her father Kaido and imitated by Yamato, in which she lunges forward at her target with blinding speed and swings her kanabo horizontally, striking the target with tremendous force. The attack was first seen used against Ulti in her full-beast transformation, knocking her out instantly. It is called Thunder Bagua in the VIZ translation. However, while Kaido uses only one hand to swing his kanabo, Yamato swings it with both hands instead, and Ulti considers this attack to only be half as powerful as Kaido's, calling it Raimei Yonke (雷鳴四卦? literally meaning "Thunderclap Four Trigrams;" Viz: "Blunder Bagua") instead, though the people around her pointed out that it still hurt her greatly.
At some point in the past, Yamato went to her father Kaido and told him that she wanted to be the great samurai Kozuki Oden, resulting in Kaido beating her. She was present during Oden's execution in the Legendary Hour, and became very sorrowful at the samurai's death. Later, Yamato found Oden's logbook in Kuri and held onto it dearly while starting to emulate everything about Oden. Yamato began presenting as a man to emulate Oden's gender, and has since been widely referred to as Kaido's son. At an unknown point in time, Kaido placed exploding shackles on Yamato, preventing her from leaving Onigashima.
Four Emperors Saga
Wano Country Arc
On the day of Kaido and Kurozumi Orochi's party during the Fire Festival, Yamato disappeared from Kaido's mansion to look for Luffy. She passed Eustass Kid's group which raised a small commotion, and ended up finding Luffy fighting Ulti near the front entrance of the mansion. Yamato used her kanabo to knock Ulti out in one blow, and introduced herself as she tried to take Luffy to a private spot to talk. Luffy had no desire to meet with Yamato and so attacked her, but Yamato managed to counter his attacks before the duo engaged in a powerful and destructive clash. In the immediate aftermath of the clash, Yamato took Luffy to the attic and was able to get him to stay and talk for five minutes. As Yamato took off her mask and revealed her real appearance, she told Luffy about her devotion to Oden and asked him to fight with her to achieve the legendary samurai's dream of opening Wano's borders. When Luffy was incredulous, Yamato remarked that Luffy reminded her of Ace. During her conversation with him, Yamato revealed to Luffy not only why she never left Onigashima (despite her wanting to do so) but also her desire to leave Wano with his crew. They then listened to Kaido's speech, but they fell out of the attic when the floor below them collapsed. When Yamato heard that Kaido planned on making her the next shogun of Wano, she immediately refused.
As they fought through the Beasts Pirates, Luffy informed Yamato that Momonosuke and his retainers were alive the whole time. Luffy then removed Yamato's handcuffs and tossed them away before they detonated and caused a huge explosion that sent them flying to the Performance Stage. Realizing that her father was really willing to kill her, Yamato disowned Kaido.
- "Yamato" (
大和?), meaning "Great Harmony", is an ancient name for Japan (originating from the Yamato Province) and can can also refer to the Yamato period of Japanese history, which lasted into the 8th century. Relating to that, Yamato is the dynastic name of the ruling Imperial House of Japan and further refers to the dominant ethnic group of Japan, the Yamato people. Otherwise: