The Djinn are a prominent race in the Dragon Ball universe. They are magial beings with unusual powers, usually created to serve a kind of purpose. Boo was a mistake however and served no purpose but to destroy, until the good souls he consumed tamed him. Mr. Boo created a wife named Booby, and together they greated a baby by the name of Baby Boo. That was the beginning of a new race on Earth, the race known as the Djinn. However these are a special race of djinn, there still exist other djinn such as the assistant to Kami-Sama, Mr. Popo. Even Shen Long and Porungacould be interpeted to be kinds of djinn.
The Djinn that descended from Mr. Boo are optimistic and joyful as a people, and dedicate themselves to making fun times for others, exemplified by Boo World, a theme park. They can become dangerous if angered or made confused, however.