The Kais (界王 Kaiō, lit. "King of Worlds") are the kings of an area of the universe in the Dragon Ball series. There are five Kais, with four of them controlling a particular quadrant of the living world and the fifth supervising them. Kais are deities and possess godly ki, as evidenced from Zamasu, Goku Black and Future Zamasu possessing godly ki, as they were the North Kais of Universe 10.
The Kais and Supreme Kais seem to be based on the in Hindu scriptures ( ) and Buddhist faith ( ). There are generally four main guardians, sometimes eight, with two additional guardians who govern and protect space, for a total of ten gods (like the Kais and Supreme Kais).
The Kais originally come from a planet called World Core, which is basically a larger version of the planets that the four Kais call home (such as King Kai's Planet). On the planet, there are gigantic trees, the Kaiju, and the Kais are all born as Core People from the fruit of those trees. Core Person average life expectancy is said to be 75,000 years. They live leisurely lives, studying various things at a school-like castle, until one of the Kais passes away. Then, they will draw lots among themselves to choose who will take the dead Kai's place and become the new Kai. However North Kai apparently retains his position despite his death during the Cell Games.
Kings of the universe
There are five Kais in Universe 7. Four of them are given the job of controlling a particular area of the universe, and overseeing the local deities (Guardians) on each planet of their quadrant. They are called the North Kai (this position is held by King Kai in the local Earth galaxy), the West Kai, the South Kai, and the East Kai. The fifth one is a Grand Kai who oversees them all.
Above the Kais there are Supreme Kais who rule over the entire universe, with a Daikaioh overseeing them. While the lower Kais watch over the living world, the Supreme Kais watch over both the Other World and the living world.
The Kais live in the Other World; they are among the few living residents in Other World. They are considered immortal, in the sense that they refer to residents of the living world as "mortals," but can still die of unnatural causes (as King Kai does, when he is inadvertently killed by the self-destructing Cell), however since they are already in Other World it doesn't really affect them in the long run (however, King Kai did receive tons of laughter and bullying from his fellow Kais for being dead). The Kais are also known to have a love for fancy cars and each Kai owns one.
During the events in the series, Kais prove not to be strong enough to oppose the villains directly, though they seem to influence the process by giving wise advice or providing training. King Kai has amazingly powerful telepathy skills, being able to transfer his thoughts to the whole planets or even galaxies, and he also teaches Goku highly useful techniques such as the Spirit Bomb and the Kaio-ken attack.
In the Dragon Ball Z: Bojack Unbound movie, King Kai explains that in the past, he and the other three Kais (South, East, and West) took it upon themselves to stop the evil galactic thug Bojack. To do so, they combined their power and imprisoned Bojack and his followers on a planet (a star in the dub) at the far end of the galaxy. Bojack and his henchmen were later set free when King Kai's planet was destroyed and King Kai was killed by the self-destructing Cell; this caused the seal which bound Bojack to break.
In addition to Grand Kai and the four Kais, both Chronoa and Zamasu have held the rank of Kai with Zamasu being the former North Kai of Universe 10. However, both were eventually promoted with Chronoa becoming Supreme Kai of Time while Zamasu became an apprentice Supreme Kai under Gowasu. This shows that Kais can be promoted to the rank of Supreme Kai.
Demon Kai are evil Core Persons that rule over the Demon Realm. Though it is unconfirmed if they are Demon Kai, Dabura, Mira, and Shula have all been referred to as Kings of the Demon Realm and Fu was seen by Dabura as a potential successor to take his position as King of the Demon Realm. Mirayo from Dragon Ball Fusions is also referred to as a former Queen of the Demon Realm though again it is unconfirmed if she is a former Demon Kai.
- Universe 7
- Universe 10
- Zamasu (former North Kai; deceased)
- Every Kai from Universe 7 has some form of eyewear: King Kai wears black Teashade sunglasses, East Kai wears red Jackie Ohh sunglasses, West Kai wears a blue monocle, South Kai wears white Jackie Ohh sunglasses, and Grand Kai wears black Wayfarer sunglasses.
- However, this does not hold true for either Chronoa or Zamasu when they held the rank of Kai.
- North Kai and South Kai are the only two of the five Kais of Universe 7 that appear in the Dragon Ball manga.
- Although not appearing, Grand Kai is mentioned twice in the manga, by Piccolo and Dende in Majin Buu Saga.
- Zamasu and his future counterpart are the only known Kais not to be native to Universe 7 as both were previously the North Kai of Universe 10 within their respective timelines.
- Chronoa is the only Kai known to wear Potara earrings even before her promotion to Supreme Kai.
- Grand Kai is the only Kai who wears clothing other than his formal attire as he is known to dress causally at times.