Kaio (界王 Kaiô, literally, King of the Worlds), North Kaio (北の界王 Kita no Kaiô, literally, King of the Worlds of the North), or King Kai in the Funimation dub, is a hero in Dragon Ball Z and Son Goku's final martial arts teacher, and later mentor. He also taught Piccolo, Tenshinhan, Yamcha, and Chaozu. His planet is at the end of a long winding road known as Snake Way, where he teaches powerful, new techniques such as the Genki Dama and Kaio-ken. Despite the fact that his planet is around 100 feet in diameter, its gravity is 10 times greater than Earth's. He has a monkey named Bubbles and a motor-mouth grasshopper named Gregory as pets. He is the Kai from the north of Universe 7. He has a heated rivalry with West Kai.
Kaio first meets Son Goku when Goku journeys to his planet to seek his training. Kaio teaches Goku the Kaio-ken attack, which doubles the users power and a red aura which surrounds them.
Androids and Cell Saga
|“||No, that's not Krillin's move! That's the last technique Frieza used against Goku! And if Cell thinks he cannot win, he may destroy earth just like Frieza destroyed Planet Namek! That darn, Dr. Gero! How could he unleashed such an evil monster on Planet Earth.||„|
|~ King Kai in Cell's Bag of Tricks|
- Son Goku
- Many other alien warriors