Here is a guide of all the holy people in DBZ, including Kaious, Kaios, and Planet Gods.
Dai Kaiou: This is the god of gods, and ruler of all lower deities and civilians of every planet. Majin Buu absorbed him. This is where Buu inherited the slanted eyes, fat body, and kind characteristics.
Kaioshins: There were originally four Kaioshins. One each for the North, South, East, and West. Three were killed by Majin Buu. Rou Kaioushin was the only one left, but he was accidentally locked inside the Z-Sword. A new Kaioushin was then in charge, East Kaioushin. He has a bodyguard named, Kibito.
Grand Kaio: This is the Kaio (not to be confused with “Kaiou”) who was made the Master of the King Kaios. He resembles R/R Army scientist, Dr. Gero.
King Kaios: These Kaios were established after Majin Buu killed Dai Kaiou and the Kaioushins. They each reside on a tiny planet, in the directional sector of the universe of which they rule. They hold the “Heaven’s Budoukai”, where they each put in there best warriors (all dead) to fight each other. Some warriors have been dead for over 5,000 years. Son Goku, however, had only been dead for 7 years.
Kami-sama: He is the God and guardian of Planet Earth. Long ago his father, Kattatzu, lived on planet Namek. Because of war on his planet, Kattatzu sent his son, Piccolo, to planet earth. Piccolo developed two personalities. The evil personality was each so distinct, that Piccolo had no choice but to rid himself of it, in order to be pure. The evil Piccolo and was known as “Piccolo Daimao: The Demon King”. Since the other Piccolo was pure good, he was made God of Earth. He dropped “Piccolo” and just used his title, “Kami”, the Japanese word for “God”. As for Piccolo Daimao, Son Goku killed him. So he asexually produced a child, to avenge himself. The child, Piccolo Junior, eventually joined the good side. Later he merged with Kami-sama. Kami-sama was now Piccolo once again.
Dende: Piccolo is a great fighter, so he needs time to train and meditate. Therefore he had to relinquish his duties as “Kami”. The Earth needed a new God, so they turned to Dende. Dende is a descendant of the Holy Namekian, Guru. Dende, throughout the later half of Z and all of GT, remained God of Planet Earth.
Mr. Popo: It is not clear exactly what Mr. Popo is, but he seems to be a combination of the Pokemon “Jynx” and Fat Albert. He has always been around. Ever since Son Goku fought him during the Piccolo Saga of Dragonball, he has been a friend and current resident/groundskeeper of Kami-sama’s Lookout. He even turned up in the DBZ OVA; “Plan to Destroy the Saiya-jin” to warn the Z-fighters of the Destron Gas that was polluting the world. Although he is not technically a God or Deity, he does deserve credit as a guardian of planet Earth.
Karin: “Korin” in the English anime, he has always been there for the Z-fighters, rather it’s with a lousy joke, or a good dose of Senzu. He lives in the Holy Land of Karin, atop the high-in-the-sky Karin Tower, where both Kame-Sen’nin and Son Goku climbed trekked to the top, in order to achieve the top physical strength. Karin keeps locked away a mystical flowerpot. In which, one can make a dangerous journey to the Darkness God, who has the “Super Holy Water” which will grant its drinker either unrivaled power…or an excruciating demise!
Emma-Daio: “King Yemma” in the English anime, he is the Judge of Heaven and Hell. It is his job to decide who goes where, and if that spirit is granted its body. Emma-Daio sometimes awards special spirits both their bodies AND a chance to train with King Kaio-sama, or a pass to the Sacred Planet of Kaiou.