From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Demetrious is a Kanassan.
Demetrious appeared in Dragon Ball Z: Bardock: The Father of Goku. He was able to draw blood on Great Ape Pumbukin with a small, yet powerful, energy blast. After he told his commander of his success in injuring the Great Ape Saiyan, he was subsequently stepped on and killed.