From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Genies are a race of peaceful creatures.
Genies did not have the ability to grant wishes (unlike in many other works of fiction involving them). They also seemed to have extremely long, perhaps eternal, life spans. Mister Popo was the only known Genie. Although he did not look like it, he was also a great martial artist. They used magic carpets to travel and were pretty agile. Popo was the assistant to whomever happened to be Planet Earth's Kami at the time.