The Kaios are the gods of the universe. They have the power
to keep peace in the universe. How the system works:
The highest god is the Grand Kaioshin. He has a bodyguard
called Kibito.
Below the Grand Kaioshin are the North, East, South, and West
Kaioshins, each ruling over one direction.
Below the Kaioshins are North, East, South, and West Kaios.
The main Kaios and Kaioshins in DB-Z-GT:
King Kai, aka North Kaio, is the North Kaio for the East Kaioshin. East Kaioshin
appears in the Buu saga of DBZ and takes part in the tournament. He later
fuses with Kibito, who also takes part, to form Kaiobit.