Rather than Kaiōshin-sama making planets, he is able to provide the impetus for them to be born. Also, he will sometimes divide up one planet and increase the number of planets. He will even do things like create life-forms, or transplant them from another planet, but his basic job is to watch over the numerous planets. Because the number of planets is so very large, the four Kaiō-sama help him out as well. They intervene if it appears that the world’s balance will crumble, but normally, they merely act in an advisory role for new life-forms, and don’t get involved. In order to provide a balance to the constantly increasing number of planets, the God of Destruction destroys [them], but he does not act on Kaiōshin’s orders; he destroys according to his own individual judgment. Except, he is capricious, so he will destroy even an important world without a second thought, or when he finds it bothersome, let someone else act as an agent of destruction.
— “Dragon Ball Chōzenshū 1: Story & World Guide” (p. 31)