At some point after Kaido had partaken of the fruit, he had his Lineage Factor extracted by Vegapunk, who used it to create an artificial Devil Fruit granting the same ability, though the result was deemed a failure; said fruit was eventually consumed by Kozuki Momonosuke, who since can become a pink dragon.
Strengths and Weaknesses
This fruit enables the user to turn into a giant, serpentine, blue-scaled dragon—an Eastern dragon (龍 Ryū?) called "Azure Dragon"—and into a human-dragon hybrid. Apart from the scales, acquired dragon features include horns (a second pair in Kaido's case), sharp fangs, and arms with clawed hands. In his full Beast Form, Kaido grows to rival a small town in size, making this the largest yet-seen Zoan transformation. His Human-Beast Form, while not as colossal, is nonetheless very large and, in shape, comes closer to his Human Form, with scales on his arms, outer torso, back, and legs as well as six horns on his head, claws on the hands and feet, and a long tail.
As with all Zoans, the transformation significantly boosts the user's physical abilities. The full dragon form's strength befits its sheer size, as the user can severely damage structures like houses merely by brushing by them. When Kaido flew around Okobore Town in a drunken stupor, it was believed that, if he continued wreaking havoc senselessly, not just the town, but Kuri itself could get wiped out. The user's arms, while relatively small and thin compared to the rest of their dragon body, are still extremely strong, a single swipe of which can send someone flying with great force. In the anime, the full dragon form's power is more exemplified, with Kaido shown causing intense, gusty shockwaves simply by moving through the air or being thrown around, as well as with a mere puff or burp. He was able to send Monkey D. Luffy flying with immense force using a tail swipe, and easily overpowered Luffy's Haki-imbued use of Gear Third with one of his dragon hands and by thrusting forward his head. Further, in contrast to the user's size, they can move about at great speeds.
The scales covering the user's dragon body are noted to be extremely durable. Blows of incredible power, including ones strengthened by regular Busoshoku Haki, have proven utterly ineffective at hurting Kaido—e.g., when in full dragon form, he shrugged off a nonstop pummeling by Luffy's strongest Gear Third attacks, without being scathed in the slightest. Nonetheless, as with Kaido's extremely tough human skin, his dragon scales can be penetrated, and blood drawn from him, using attacks that bypass external defenses, like advanced-grade Busoshoku Haki (or "Ryuo").
The user's Human-Beast Form sees their draconic strength focused in significantly smaller frame, with this diminished size granting them a boost in agility and speed while seeming overall better adapted to close combat. The user also retains access to their elemental attacks, like their fire breath (though with a smaller range in accordance with their smaller body size, compared to their full dragon form).
Beside the transformation itself, the fruit bestows multiple supernatural abilities, the most out of any Mythical Zoan seen so far. The most prominent of these is the power to conjure Flame Clouds (焔雲 Homura-gumo?), with which the user can travel through the air by using them as footholds, effectively enabling flight; Kaido's dragon arms tend to be continuously encircled by fiery rings, which may be said clouds helping him fly. Also, the Flame Clouds can be used to lift other objects, including entire islands, into the air and move them, for extended periods even and while using their other powers simultaneously. Furthermore, there is no apparent need for the user to transform in order to manifest (or at least maintain) Flame Clouds.
In addition, the user can create and control various elements as a dragon, both in their full Beast and Human-Beast Form. Most commonly seen is a concentrated, scorching blast of fire that the user breathes out, which can travel many kilometers in the span of seconds and instantly decimate a large, earthen structure. Aside from flames, the user can launch lightning bolts while roaring and cutting blades of wind while blowing, on top of stirring up strong, fast-rotating tornados.
Due to the massive amount of space the user takes up after entering their full Beast Form, their ability to move about in enclosed spaces is greatly hindered. Additionally, depending on how much care is given to their surroundings, the user's transformed body having a propensity for collateral damage may become a liability for allies. The user's massive body also leaves more openings, making them an easier target for attacks, especially multi-directional assault from more than one enemy.
While the user's dragon scales are immensely tough, the user remains vulnerable to attacks that, by their nature, bypass external defenses. Usage of advanced, emission-type Busoshoku Haki, in particular, can allow opposing parties to hurt the user's dragon form (even if used by enemies that are physically far weaker than the user), as can Haoshoku-"infused" attacks. Other examples of effective attacks reaching the target's insides are ones utilizing powerful soundwaves, or the Ope Ope no Mi's "surgical" techniques.
Otherwise, the user is affected by the standard Devil Fruit weaknesses.
Kaido uses this fruit's power frequently in combat. He typically starts out battles in his full dragon form and transforms back into a human upon getting more serious, his base form seeming more suited for intense and up-close, one-on-one combat. If his adversaries prove strong enough to handle both his human and full dragon forms, Kaido will enter his Human-Beast Form—possibly the strongest of his three basic forms.
When engaging foes in his full dragon form, Kaido frequently hovers a considerable distance away from them, out of melee range, so as to assault them with destructive, long-ranged attacks of various elements, like his fire breath. In actual close combat, he has been seen chomping down on opponents within reach or swiping them with his claws.
When entering his Human-Beast Form, Kaido takes to wielding his kanabo like he does in his Human Form. With the boost he gains in strength, he can swing the club with extreme force, causing massive shockwaves and striking melee blows too dangerous for most enemies to take head on. Becoming far more agile than as a full dragon, Kaido can move around by slithering through the air, using his dragon tail to propel himself forward or upwards, which aids his offensive moves.
Both in and outside of battle, Kaido can create his "Flame Clouds" to use primarily as footholds in order to take flight; he can thus easily travel between islands by crossing the open sea, such as between Onigashima and the Wano mainland. He can also levitate objects, even gigantic ones, by creating enough of his clouds to surround whatever he wishes to float away. This was chiefly seen when Kaido sent the entire island of Onigashima aloft to proceed with his New Onigashima Project, levitating the island toward Wano's Flower Capital.
- Bolo Breath (
熱息Boro Buresu?, literally meaning "Heat Breath"): Kaido's most frequently seen attack, which has him gather fire inside his mouth before "breathing" it out into a huge, conical blast toward his target of choice. This blast travels rapidly (in the anime covering a tremendous distance within moments) and is extremely powerful, able to instantly decimate large structures, such as a castle's ruins, while surrounding terrain like mountainscapes is left flattened, blown to bits, and scorched. Despite this move's strength and scope, it can be countered by Kitsunebi-ryu. When Raizo cast this attack back at Kaido via his scrolls, it proved able to somewhat damage the latter's own dragon body. When used in his human-hybrid state, Kaido's Bolo Breath is much smaller in scale, enough to shatter rock but not to cause widespread destruction, and thus is suited better for close-range combat. Bolo is a term used in Central America and Mexico meaning "drunk". In the Viz manga, the technique is called Blast Breath.
- Kaifu (壊風 Kaifū?, literally meaning "Destructive Wind"): An attack where Kaido blows strongly, thereby creating powerful, crescent wind blades that can easily cut through solid stone as well as human bodies. The move was first seen being used in Kaido's fight against the Nine Red Scabbards on the roof of Onigashima's Skull Dome, severing Kikunojo's left arm, but was not named until Kaido used it against the Worst Generation members on the same roof. Denjiro described the wind blades as kamaitachi (かまいたち?), a Japanese term for cutting whirlwind derived from the yōkai Kamaitachi. The Viz translation of the attack is Demolition Gust.
- Tatsumaki (龍巻 Tatsumaki?, literally meaning "Dragon Twister"): Kaido spins his serpentine body into a coil to summon several tornadoes around him. Because of their wind speed, these tornadoes can pull people away from the ground and within Kaido's range in midair, where he may chomp down on them. The technique was first seen in use against the Worst Generation members on the Skull Dome's roof. It was effective in capturing a defenseless Monkey D. Luffy, but Roronoa Zoro was able to neutralize it with his own Kokujo: O Tatsumaki technique. The name of the attack is the Japanese word for "tornado" (竜巻 tatsumaki?), but with the kyūjitai of the "dragon" (龍?) kanji instead of the shinjitai (竜?). In the Viz translation, the technique is called Dragon Twister.
- Tatsumaki Kaifu (龍巻壊風 Tatsumaki Kaifū?, literally meaning "Dragon Twister Destructive Wind"): An attack that combines Tatsumaki and Kaifu. Kaido spins the lower portion of his elongated dragon body at great speeds, simulating a tornado himself. He then blows crescent wind blades towards his own spinning body, making the blades fly unpredictably in various directions. Kaido also roars lightning while performing this technique, but that itself does not seem to be part of the attack. This move was first seen being used in Kaido's fight against the Worst Generation. The Viz manga calls the attack Dragon Twister Demolition Breath.
On the day of the God Valley Incident 38 years ago at God Valley, Charlotte Linlin gave this fruit to Kaido, who at the time was her crewmate on the Rocks Pirates. Big Mom considers this a debt for life that Kaido cannot escape from.
Sometime within the 34 years of him eating the fruit, Kaido was in Marine captivity, and the scientist Vegapunk extracted his Lineage Factor for the purpose of creating an Artificial Devil Fruit. This replica fruit, while deemed a failure, was later eaten by Kozuki Momonosuke, shortly before the present day after having been stored on Punk Hazard. Momonosuke thereby gained a dragon transformation much like Kaido's (even coming with the ability to produce Flame Clouds), albeit Momonosuke's power was initially out of his control.
- This fruit's name is currently the only Devil Fruit name with both its double syllables as vowel sounds with no consonant: "Uo" (ウオ?). Thus, it is (minus the "Model" designation) one of the shortest romanized Devil Fruit names.
- The fruit's name is reflected in Kaido's signature laugh: "Worororo/Uorororo" (ウォロロロ/ウオロロロ?). This quirk is shared with other characters: Whitebeard with the Gura Gura no Mi, Perona with the Horo Horo no Mi, and Streusen with the Kuku Kuku no Mi. Kaido's case is still unique in that only the first part of his laughter references his Devil Fruit's name.
- Ironically, despite a line of Zoan models being named after dragons (the Ryu Ryu no Mi) and this being the only known Devil Fruit ability to actually enable transformation into a dragon (the fruits of the Ryu Ryu no Mi series granting dinosaur transformations), this fruit is not named after dragons but fish.
- While this fruit is classed as Mythical Zoan, with dragons explicitly stated as having mythical status in the One Piece world, dragons have also been real existences. Namely:
- The dragon killed by Shimotsuki Ryuma in Monsters (confirmed in the Thriller Bark Arc and later the Wano Country Arc to have canonically occurred). Still, said dragon's origins are not known, and it more so (per its depiction in Monsters) resembled a Western-style dragon as opposed to the East Asian dragon form of Kaido.
- The dragons on Punk Hazard, artificial lifeforms created by Vegapunk, which are also more Western-like dragons.
- Kaido's dragon powers were first hinted at in the Punk Hazard Arc, as Kin'emon expressed deep resentment against one of Vegapunk's artificial dragons while fighting it, and when Brook commented that the samurai's hatred was reminiscent of someone trying to avenge their dead parents, Kin'emon replied that it was "nothing less", referring to Kaido being responsible for his master Oden's death.
- According to Oda, Roronoa Zoro would have this Devil Fruit if he was allowed one, albeit "consumed" by one of his swords.
- In the video game One Piece: Pirate Warriors 4, Kaido as a playable character has shown the ability to unleash ice attacks. If Kaido can do the same in the canon story remains to be seen.
- When Kaido first appeared in his dragon form, he did so by emerging through dark, swirling clouds in the sky. This may be a nod to Shenron, a magical, wish-granting, Eastern dragon god from the Dragon Ball franchise, as Shenron's arrival is similarly accompanied by dark clouds covering the sky.
- The Azure Dragon (pinyin: Qīnglóng) is a Dragon God in Chinese culture and myth, known as one of the Four Symbols (also, "Four Guardians" and "Four Auspicious Beasts") of the Chinese constellations—next to the Vermillion Bird, White Tiger, and Black Tortoise. It represents the East (in myth associated with the color blue), springtime, and the wood element.
- In Japan, the Azure Dragon (Seiryū in Japanese) is one of the four guardian spirits of cities, said to protect the eastern city of Kyōto. Corresponding to this may be the fact that Kaido lives on Onigashima, which is to the East of the Wano mainland.
- The appearance of Kaido's dragon form, and of the clouds he creates, may be inspired by Utagawa Kuniyoshi's ukiyo-e paintings.
- This fruit, with its "fish" designation, references the connections present between dragons and fish in East Asian (especially Chinese) mythology:
- In general, fish are some of the several animal resemblances Chinese dragons are said to bear, in addition to the animal-like forms they can take on. For example, Chinese dragons are generally thought to have the scales of carp. In their roles as controllers of the seas and of rivers (even divine rulers thereof, in case of the Dragon Kings), dragons are also held in mythology as rulers of, and even originating from, fish.
- Particularly, the fruit may draw inspiration from the Chinese Dragon's Gate myth, wherein the Dragon's Gate is located atop a waterfall cascading from a legendary mountain, on the Yellow River. Many carp (lǐyú) swim upstream against the river's strong current, but few are capable or brave enough for the final leap over the fall. If a carp successfully makes the jump, it is transformed into a majestic dragon. Thus, a Chinese dragon's large, conspicuous scales indicate its origin from carp.
- Another example of the connection between dragons and fish in Chinese mythology is the chīwěn, a fish-like, hornless dragon said to be one of the "nine sons" of the Dragon King.
- Kaido's appearance may have foreshadowed his fish-based dragon powers, namely his sizable, orange-yellow scale tattoo on the left side of his torso, resembling fish scales (orange and yellow being major colors of koi fish), as well as his mustache, possibly designed to evoke the image of a carp's "whiskers".
- Possibly touching further on the relation between this fruit and koi fish is Kaido's birthday, May 1st, which is "Koi Day" (鯉の日 Koi no Hi?) in Japan, a celebratory day established by the National Carp Raising Promotion Council headquartered in Namegata City, Ibaraki Prefecture.
- Further in relation to Asian/Chinese dragons or lóng:
- Just as Kaido is said to be the world's "Strongest Creature", Eastern dragons are seen as symbolizing power and so are extremely powerful, especially Dragon Gods.
- Eastern dragons were traditionally believed to be able to adopt human form, just like Kaido can shift between human and dragon form as a Zoan user.
- Asian dragons are commonly depicted with hair: a flowing mane, long, tendril-like whiskers appended to the sides of their snout, and a beard. This matches Kaido's wild mane, long and thin mustache, and beard that he retains in dragon form.
- Kaido's dragon form has four claws/toes: four-clawed dragons are customarily depicted in Mongolia and Korea (as opposed to the three claws common for Japanese dragons). In China during the imperial dynastic era, four-toed dragons symbolized imperial aristocracy (e.g., princes), denoting imperial ranking just below the emperor himself, who is symbolized by five-toed dragons.
- Eastern dragons that breathe fire are minor in lore. Those who do were said to be rather violent individuals or sent from the heavens to earth as punishment. Kaido's ability to breathe a fire blast (contrary to the Eastern dragon's prevalent water association) is likely inspired by European conceptions of fire-breathing dragons or "firedrakes".