Napapoom Rodsuwan

Kaidou of the Beasts, renowned as the world's "Strongest Creature", is the Governor-General of the Beasts Pirates and 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 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 Luffy's hands, the World Economy News Paper released a new listing of Four Emperors, with Kaidou no longer being included among them.[26] After his defeat, Kaidou is now referred to in Wano's folklore retelling as "Dragon King Kaidou" (龍王カイドウ Ryūō Kaidō?).

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, and the main antagonist of the Wano Country Arc and Saga.

Kaidou was defeafed by Luffy.

However, after defeating Kaidou during the Raid on Onigashima, Luffy was officially declared as one of the Four Emperors by the World Government along with Buggy, replacing Kaidou and Big Mom.