Kaido

"Dammit! Hurry up, Joker! Make preparations for the final battle! I don't care if this boring world is destroyed! Let's start the greatest war the world has ever seen!"

- Kaido

Kaido (in Japanese: カイドウ, Kaidō) is the main antagonist of the Wano Country Arc and one of the main antagonists of the Yonko Saga and a major antagonist in One Piece. He is the villainous captain of the Beast Pirates and one of the Four Emperors in the New World. He is the one who killed Gekko Moriah's old crew. He also tried to attack Whitebeard when he tried to save Ace but was stopped by Shanks. He is also considered to be The Strongest Creature in the World and has an army of 500 artificial devil fruit users in his crew of the Beast Pirates and is greatly feared as he himself cannot die.

He was voiced by Tesshō Genda.

Personality
Not much is known about Kaido's personality, but it is implied by Trafalgar Law that he has a temper as he stated Kaido would even kill Doflamingo if something happened to the SMILE factory. He seems to enjoy suicide attempts as a hobby because of his seemingly indestructible and adamantine body. It is also mentioned that Kaido is not up for negotiations which caused Doflamingo, who is usually adventurous and fearless to fear having the thought of going up against him. He is also arrogant, presumptuous, and prideful in himself seeing Doflamingo and the Supernovas as weaklings. When he is enraged, he would also take his rage out on his subordinates by attacking them.

Powers and Abilities
As a Yonko, Kaido is an extremely powerful individual. He is stated to be so strong that Doflamingo, an incredibly strong fearless pirate with a powerful crew became terrified at the thought of having to face him. His intimidating and treacherous reputation seemed to make Doflamingo ponder on fighting the marine admirals when Law suggested quitting being a Shichibukai or staying to deal with the angry Yonko. He is even strong enough to fight Shanks (another powerful Yonko) when the latter intercepted him from attacking Whitebeard. Despite Kaido's menacing capabilities, not much is known about his abilities.

He has many powerful subordinates such as Jack and after hiring Donquixote Doflamingo and Caesar Clown he was able to make a large army. But now that Doflamingo has been defeated, he lost his means of doing so.

Physical Prowess
Kaido is considered to be the strongest "creature" in the world. He is said to have survived countless situations where he would have been killed or executed. He has survived many types of torture and even execution. His body is strong enough to even shatter spears that would stab him. He attempted to commit suicide dozens of times but would always survive every time even to the point of it being a hobby. He is stated to be a being that is near immortal and simply cannot be killed. For instance, he fell from Ballon Terminal (a sky island about 10,000 meters above the ground) to the island where Eustass Kid's alliance was at and survived it with no scratches but just a headache.

He appears to have immense strength as he defeated Eustass Kid, a notorious pirate with a bounty of 470,000,000 berries and emerge without a scratch even taunting him for his loss.

Past
Kaido, at one point, met Big Mom. Big Mom did Kaido a favor and Kaido owes her a debt in return the likes of which is a lifelong debt.

20 years ago, Kaido and the Beast Pirates caught onto Kurozumi Orochi's plot to take over Wano Kuni. Kaido entered into an alliance with Orochi to take down Kozuki Oden and the Kozuki family. With the Beasts Pirates, Kaido pillaged Oden's castle and murdered many members of the Kozuki Family. Momonosuke, Kin'emon, Kanjuro, Raizo, and Kiku managed to escape from Kaido with Kozuki Toki's time-time devil fruit. Kaido resided in Wano Country on an island called Onigashima where he has political power over the entire country. Over time, Kaido sets up multiple factories on Wano Kuni to manufacture weapons and tools. As a result of this practice, most of the food in the Wano Country is uneatable and the water is undrinkable. Kaido's and Orochi's food and water supply, however, are clean. Kaido also allows his men to have authority over some parts the country.

Kaido met Doflamingo and Caesar and became affiliated with them. In their business deal, Doflamingo would help produce artificial devil fruit to enhance Kaido's army with the help of Caesar. At some point, Kaido slaughtered Gekko Moriah's comrades when the latter traveled to the New World.

Summit War Saga
Before the Marineford War, Kaido attacked Whitebeard but Shanks stopped the fight.

Time Skip
Kaido learned that Momonosuke, Kin'emon, Kanjuro, Raizo, and Kiku were in the Wano Country. Kin'emon and his allies with the exception of Kiku left Wano. When the Kozuki retainers made it passed Zou and onto Dressrosa, Kaido ordered Doflamingo to capture them. However, Momonosuke ended up getting captured Caesar's men in the process. At the same time, Kaido was also interested in capturing Raizo who was on Zou. Jack tried to track Raizo.

Dressrosa Arc
Luffy and Law decided to create an alliance so that they can take down one of the Yonko, Kaido. With the SAD factory on Punk-Hazard destroyed, the Straw Hats and Law now want to destroy Kaido's SMILE factory in Dressrosa so that it can lower Kaido's army power.

After learning about Doflamingo's defeat and the destruction of the SMILE factory by the Straw Hat and Heart pirates alliance, his men tried to inform him about the news. Kaido, however, appeared on the Sky Island called Balloon Terminal. He attempted to commit suicide by free falling at a height of 10,000 meters to hit the ground below. He landed at the base of Eustass Kid and survived the fall complaining about a headache. He came out the hole and began speaking about Joker and his desire to make him prepare for a massive war.

Zou Arc
Kaido appeared on an island with his subordinates. He was drinking sake after hearing about Doflamingo's defeat at the hands of Luffy and Law. He was sad at first that he would not be able to achieve his goals of getting a devil fruit only crew. His depressive mood turn to wrath when he saw the wanted posters of Luffy and Law and attacked his crew mates with a giant mace out of spite. Kaido said that their decision to take down Doflamingo have now caught his attention and that he will be going after them. He began insulting Kid who happened to have been defeated in their confrontation before. Kaido stated that the Supernova are simply playing a pirates game.

Reverie Arc
Kaido reads the newspaper of Luffy's actions in Big Mom's territory and wondered why he was in her territory. A couple days later, Big Mom called Kaido wanted to form an alliance with him but he refused. Big Mom told Kaido to not kill Luffy when he makes it to Wano Country as she wants to kill him to save her reputation. Big Mom also reminds Kaido of his debt to her but the latter said it was a long time ago. Kaido refused and threatened to kill her if she comes to Wano Country. Big Mom insists on working together like they used to do in the past.

Trivia

 * Like Big Mom, Kaido's appearance changed from the time he was mentioned until he made an appearance. This was possibly because it was an earlier design.
 * Kaido is the last Yonko to make an actual appearance in the series.
 * Kaido was first mentioned in Chapter 432 by Garp in his conversation about the Yonko. He makes an actual appearance in Chapter 795. This makes it 363 chapters that Kaido was mentioned before his actual debut.
 * Kaido's name means temple or church.