Olibu is King Kai's top fighter in the Other World Tournament, representing the North Quadrant. He's basically a legendary figure—King Kai claims most of Earth's heroic myths actually stem from Olibu's real deeds during his lifetime, and there's some suggestion in the anime that Korin Tower itself was built to commemorate him.
He's an imposing guy: fair-skinned, blonde-haired, purple-eyed, and towers over Goku by at least two feet. He's built like a tank too. His look is distinctly ancient Greek—white robes with brown suspenders and belt, white wrist and shin bands, big light brown boots, and an orange headband.
After his heroic acts in life, Olibu earned a spot training on the Grand Kai's planet. He was already 10,000 years into his training when Goku showed up. At the tournament, he beat Chapuchai but ran into Pikkon in the quarter-finals and lost. He also pops up as a cameo in Dragon Ball Z: Fusion Reborn alongside Mijorin and Maraikoh.
During the Kid Buu saga, he's shown sparring with Yamcha and taunting Kid Buu alongside Pikkon. Kid Buu nearly blasts him with the Shocking Ball but decides to chase Goku and Vegeta's energy instead. Olibu's final scene is watching Goku fight Kid Buu with hundreds of other fighters.
Content compiled by AnimeList.moe from publicly available sources.
