Kami—literally "God" in Japanese—represents the good half of a Namekian who split into two beings: himself as Earth's deity and the demon king Piccolo Daimao as his evil counterpart. In the anime, he won a divine competition against Garlic for the position, and later dealt with Garlic Jr.'s grudge-fueled challenges centuries later. For hundreds of years, he served as the planet's guardian.
When Piccolo's spawn began threatening Earth, Kami decided to intervene directly. He secretly entered the Tenka-ichi Budōkai by possessing a human fighter, making it to the semifinals before facing Piccolo himself. He attempted to seal his counterpart away using the Mafūba technique, but Piccolo turned it around—trapping Kami in the bottle instead and swallowing it to keep it safe. Kami stayed trapped until Piccolo lost his match against Goku.
By the time the Artificial Humans arrived as a new threat, Kami realized he couldn't handle it alone. He agreed to fuse back with Piccolo, merging the two halves into one being strong enough to face the androids.
Content compiled by AnimeList.moe from publicly available sources.