Kaido is one of the most popular One Piece characters. He is the main antagonist of the Wano Country arc. Kaido landed in Wano decades prior to the beginning of One Piece and took control of the entire country. He has absolutely no interest in the welfare of the people, as he only respects the strongest. During his stint in Wano, Kaido was challenged by Kozuki Oden, the strongest samurai in Wano.
Oden's skill with the sword was so incredible that Kaido couldn't even get near him. The would-be Emperor received a massive scar on his torso and was on the cusp of defeat. However, Kurozumi Higurashi distracted Oden, allowing Kaido to land a critical hit. Since then, Kaido's strength has continued to increase, and he has become widely known as the "Strongest Creature in the World." One of the main reasons behind his power is the Uo Uo no Mi, Model: Seiryu.
The Devil Fruit
Kaido's Uo Uo no Mi, Model: Seiryu is a Mythical Zoan-type Devil Fruit, and it was given to him by Big Mom while they were still members of the Rocks Pirates. The Devil Fruit grants Kaido the ability to change into an Azure Dragon at will. In his fully transformed state, Kaido was able to cover the skies above the town of Kuri. He can effortlessly raze a town to the ground by simply thrashing around. Kaido can also use an attack called Bolo Breath, which is a powerful beam capable of blowing up an entire mountaintop.
He has used Bolo Breath multiple times in the arc, and most of the time it has caused significant damage to the surroundings. Kaido can also create tornadoes that can cause problems for even the strongest of characters. Another weapon in Kaido's locker is Kaifu, or Demolition Gust. To use this attack, Kaido blows strongly, which creates powerful wind blades that can slice through human flesh like a hot knife through butter.
Hybrid Form
Like all the Zoan-type Devil Fruit users, Kaido also has access to a hybrid form. In fact, Kaido has mainly used his hybrid form while fighting Luffy. This form is smaller than his full beast form, but it makes him more agile. Due to having a smaller body, Kaido can freely dodge incoming attacks.
In his hybrid form, Kaido added Haoshoku Haki to his attacks, increasing their overall power. A single strike in his hybrid form was strong enough to instantly knock out Luffy. Kaido was also able to blitz Trafalgar Law and Roronoa Zoro without any problems. Kaido also has several drunken forms, which makes it extremely difficult to predict his moves. Even with Future Sight, Luffy had trouble keeping up with Kaido's movements. While his hybrid form is sufficient to take down most foes, Kaido also has two other tricks in his locker. One is the Flame Dragon Torch, and the other is his Devil Fruit Awakening.
The Awakening
It has not been explicitly stated that Kaido has awakened his Devil Fruit, but there are strong implications that he has. Considering Kaido was an incredible fighter, it is highly unlikely that he did not awaken his Devil Fruit, especially when Doflamingo and Katakuri had awakened theirs. More concrete evidence of Kaido's awakening was revealed when he fought Luffy atop the castle. Normally, in his hybrid form, Kaido had a long nose and two long fang-like teeth. However, at a certain point, Kaido's appearance changed. His nose became smaller, and he had more pointy teeth. This gave him a more feral appearance and very likely boosted his physical abilities further. So, why didn't Kaido use it for a prolonged period?
Oda has stated that Zoan-type Devil Fruits have their own will, and using the Awakening for too long could result in the nature of the beast taking over. The jailors of Impel Down are the perfect example of this problem. All of them have awakened their Devil Fruits, but they cannot revert to their human forms. Kaido is also aware of this fact, which is why he refuses to use the Devil Fruit's Awakening for too long. It also makes sense why Kaido's Awakening made him look more like a beast than a man.
​​​​​​Flaming Dragon
Due to the limitations of his Devil Fruit, Kaido had to find another way to fight strong opponents. Eventually, he came up with the Flame Dragon Torch. In this attack, Kaido releases an enormous amount of fire, which coats his body and takes its shape. The flame dragon is as big as the island of Onigashima, and the fire is so hot that it melts rocks.
While in this form, Kaido lunges toward his opponent and releases a bite attack that can deal severe damage. Kaido used this move as a last resort, so it does not have many variations. Needless to say, not being able to use his Devil Fruit Awakening did not make much of a difference to Kaido. He was still a ridiculously powerful character. Despite falling to Luffy, Kaido will go down as one of the greatest pirates in history.
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