Dragon Ball: Mystical Adventure (1988)

Master Roshi has succeeded at the one mission he valued most: to train Goku and Krillin to become ultimate fighters. So, he arranges for them to test their mettle at a competition hosted by Emperor Chiaotzu. Not everyone's playing by the rules, however, as a member of the ruler's household schemes to use the Dragonballs to extort money and power from the royal.