The Shin-jin race are born from the magical fruit of the "Kaiju" World Trees located on Planet Kaishin in the Otherworld, rather than in the mortal dimension. Some Shin-jin are fortunate enough to achieve the status of Kaio, "King of Worlds." The Kaios are tasked with overseeing and protecting various planets and species throughout the universe. Most Shin-jin are born with good, pure hearts, though there are a small number who are instead born filled with evil. While not a particularly strong warrior race, the Kaios do possess many incredible techniques and abilities as well as extremely long lives.
The Shin-jin were nearly wiped out during an attack by Bibidi and Bibidi's ultimate creation, Majin Buu. However, a few of the Kaios and a single Kaioshin managed to survive the slaughter and have rebuilt again over time. The Kaios have begun playing an ever-increasing role in the events of present times.
Those Shin-jin born with evil hearts are cast into the Demon Realm to become Makaios. Existing on the plane opposite the mortal universe, the Demon Realm is a place of constant violence and chaos. Simple survival requires significant strength and unending bloodlust. In this regard, Makaios are considered to be among the most powerful of Demons.
Similar to their Kaio brethren, Makaios possess incredible mystical abilities as well as savage techniques of their own.
The most powerful beings in the Demon Realm are known as Makaioshin. Before falling under the control of Babidi, the Makaioshin Dabura had ascended to take the title of Demon King. While the various warring Demon clans fight amongst themselves in service of their Warlords, they ultimately follow the King on the warpath.