Living in the “Next Dimension,” King Kai is known throughout the universe as one of the greatest fighters and martial arts teachers (although his teaching methods are rather unorthodox). His house is on a tiny planet at the end of Snake Way. The small planet has ten times the gravity of Earth, and is thus an ideal training site. His companions include a goofy monkey, named Bubbles, and a grasshopper, named Gregory. King Kai possesses a humorous, corny sense of humor (he’s always telling jokes or puns) as well as great wisdom. Fortunately for our friends, he can communicate telepathically, giving them good advice and warnings in critical situations.
Goku trained under King Kai and now wears his symbol. Yamcha, Chiaotzu, Tien, and Piccolo also train under King Kai when they are sent to the “Next Dimension.”
When Goku seeks King Kai in the “Next Dimension,” King Kai begins his training by having Goku catch Bubbles, which is no easy task with an energetic monkey and a gravity ten times the force of Earth’s. Goku catches Bubbles after only three months. His next task is to hit Gregory the grasshopper with a hammer. Goku, impressively, performs this task in three weeks. Only after these tasks increase Goku’s strength and speed, does Kai begin the personal training of Goku. In the 118 days left before the Saiyan’s return, Kai teaches Goku the “Kaio-ken” and how to gather energy from the planet into one great fighting energy ball. Later King Kai takes on the training of Yamcha, Tien, Chiaotzu, and Piccolo using the same techniques that were successful with Goku.