Kaido of the Beasts,[7][13] renowned as the world's "Strongest Creature",[14][8] is the Governor-General of the Beasts Pirates[5][11] and one of the Four Emperors ruling over the New World.[4] He is also the father of Yamato.[15][16][17]

From his base on Onigashima,[6] Kaido has occupied Wano Country along with his crew and once allied with Wano's shogun, Kurozumi Orochi,[18][19] until Kaido decided to dispose of him for his New Onigashima Project.[20] Decades ago before the formation of his own crew, Kaido was an apprentice in the legendary Rocks Pirates,[3] and he is currently in an alliance with his former Rocks crewmate and fellow Emperor, Big Mom.[21]

Kaido was first referred to by Monkey D. Garp in the Post-Enies Lobby Arc[4] and then directly mentioned by Gecko Moria in the Thriller Bark Arc,[22] with his status as one of the Four Emperors revealed after the Straw Hat Pirates defeated Moria.[23] Thus, Kaido is the third Emperor mentioned by name and the last to debut.[1] Before he debuted in person, his voice was heard in a flashback that Kozuki Momonosuke had when first disembarking on Dressrosa.[24][25]

He is the primary antagonist of the Wano Country Arc and one of the central antagonists of the Four Emperors Saga.