Dark Kai

Bumi is the fusion of Buubuu and Olormi, and the first ever fusion made upon the Ultimate Potaras. He is the Western Supreme Kai by the time of Dragon Ball Generations, and is over one million years old.

Background
Bumi was formed in a last-ditch attempt to defeat Olormi, by Buubuu placing one of his custom Ultimate Potaras on Olormi's left ear and the other on his right and fusing the two. Thankfully Buubuu's overall judgement won over Olormi's, and Bumi then began travelling the universe for the next one million years. He eventually became the Western Supreme Kai.