カイドウ 

Overview

Kaidou of the Beasts, renowned as the world's "Strongest Creature", is the Governor-General of the Beasts Pirates and was formerly one of the Four Emperors that ruled over the New World. He is also the father of Yamato.

Once a promising child soldier at the service of the Vodka Kingdom decades ago, Kaidou was drafted against his will by the Marines but managed to escape and start a career in piracy. He was invited by Edward Newgate to join the legendary Rocks Pirates as an apprentice, where he met and befriended Charlotte Linlin. During the God Valley Incident when the Rocks Pirates met their downfall, Linlin provided Kaidou with the rare Mythical Zoan-type Devil Fruit, the Uo Uo no Mi, Model: Seiryu. He then went on to form his own crew and build it up into a powerful military force determined to challenge the World Government.

After being invited to Wano Country by Kurozumi Higurashi, Kaidou joined forces with Wano Country's shogun, Kurozumi Orochi, and occupied Onigashima as his base. After a failed attempt from Kozuki Oden and the Nine Red Scabbards to overthrow him, he continued to accrue military might in Wano Country for 20 years before deciding to dispose of Orochi and proceed with his plan for the New Onigashima Project. The plan never came to fruition, however, as Onigashima was raided by the Ninja-Pirate-Mink-Samurai Alliance on that very same night and the Beasts Pirates were ultimately defeated. Following Kaidou's defeat at Monkey D. Luffy's hands, the World Economy News Paper released a new listing of the Four Emperors, with Kaidou no longer being included among them anymore. After his defeat, Kaidou is now referred to in Wano's folklore retelling as "Dragon King Kaidou".

Kaidou was first referred to by Monkey D. Garp in the Post-Enies Lobby Arc when he revealed the existence of the Four Emperors, and was then first directly mentioned by Gecko Moria in the Thriller Bark Arc, with his status as one of the Four Emperors revealed after the Straw Hat Pirates defeated Moria. Thus, Kaidou is the third Emperor mentioned by name and the last to debut. Before he debuted in person, his voice was heard in a flashback that Kozuki Momonosuke had when first disembarking on Dressrosa.

Due to his actions, he can be considered the overarching antagonist of the Dressrosa Saga, the main antagonist of the Wano Country Arc and Saga, and a major antagonist of the second half of the series.

Devil Fruit

Kaidou ate the Uo Uo no Mi, Model: Seiryu, a Mythical Zoan-type Devil Fruit that allows him to transform into a full serpentine Azure Dragon and a human-dragon hybrid at will. His full Beast Form is massive, roughly half the size of a small town, and is covered with extremely durable, blue scales, dramatically increasing the tremendous natural durability of Kaidou's body. His Human-Beast form grants him a massive increase to his speed, agility, and mobility, while further increasing his vast resilience and physical strength to even greater levels.

As a dragon, Kaidou is capable of creating special clouds called "Flame Clouds" and using them as footholds, allowing him to move through the air. These clouds can also be used to lift other objects; they are even capable of lifting an entire island out of the sea. He can also release devastating blasts of fire from his mouth, which can instantly deal significant damage to or fully obliterate large structures, such as an entire mountain and the ruined castle that stood upon it. By breathing flames in the shape of a dragon around his body, Kaidou can coat himself in a layer of heat so intense that it can instantly melt substances that come in contact with it, which discourages physical attacks. Aside from his fire breath, Kaidou can also release other elemental attacks from his mouth; he can release bolts of lightning by roaring, or invisible, sharp wind blades by blowing. By twisting his massive body, Kaidou can create tornados which can blow his enemies off the battlefield and into the air.

Kaidou has mastered his Devil Fruit powers to the level that he can access some of his draconic abilities without needing to transform, such as generating Flame Clouds to levitate Onigashima. He was even able to do so while battling against five members of the Worst Generation alongside Big Mom.

Haki

Kaidou is one of the few people in the world who can use all three forms of Haki, furthermore, only he and Monkey D. Luffy are the only characters shown so far to be able to use the advanced applications of all three forms. Law stated that he could not directly move Kaidou around inside his ROOM due to Kaidou's Haki being too strong.

Haoshoku Haki

Kaidou possesses immense mastery in the usage of Haoshoku Haki, as first shown when he clashed against a fellow Emperor and Haoshoku Haki user, Big Mom; producing a lightning effect and burst that shook Onigashima and split the heavens. Additionally, Kaidou can release extremely potent bursts of Haoshoku Haki that can damage the landscape around him and blow away opponents.

Most notably, he is among the small "handful" of users capable of using the advanced application of "infusing" Haoshoku Haki into things, particularly, his Hassaikai, signified by the thin streams of black lightning radiating from it. When used in conjunction with his natural strength and Busoshoku Haki, Kaidou can knock out powerful pirates, such as Luffy, Zoro, and Law in one or two strikes.

Busoshoku Haki

Kaidou is an immensely skilled user of Busoshoku Haki, which he is capable of imbuing into his kanabo. During the Raid on Onigashima, similarly to Katakuri, his Busoshoku Haki was strong enough to damage Luffy, who hardened both of his arms. He is capable of utilizing the advanced application of this type of Haki, projecting his Busoshoku Haki out from his kanabo, allowing him to strike opponents many meters in front of him with devastating power without the need to make direct contact, and the attack power can be increased further if the kanabo is imbued with Haoshoku Haki.

In the anime, when Kaidou uses advanced Busoshoku Haki, it is shown as a purple-colored flowing aura.

Kenbunshoku Haki

Kaidou is an extremely skilled user of Kenbunshoku Haki, as he was able to sense the "voices" of the Super Rookies in the wake of his and Big Mom's combined attack, which enabled him to tell they were still alive. He can also use the advanced application that allows him to briefly see into the future, which helps him dodge powerful blows, as shown when he avoided Luffy's Red Hawk and Snakeman attacks.

Weapons

Kaidou wields a large, black, spiked kanabo named Hassaikai as his signature weapon, which he already possessed during his apprentice days in the Rocks Pirates. Thanks to his massive strength and ability to imbue the club with Busoshoku and Haoshoku Haki, Kaidou can perform incredibly powerful strikes by swinging it, allowing him to produce large shockwaves, severely injure foes, knock mighty adversaries unconscious with a single hit, and send people flying off into the distance.