The Zarbi Supremo was three times the size of the average Zarbi at approximately twenty feet tall. He was ambitious and tyrannical, and dreamt of conquest, both on a planetary and universal scale. He fitted the planet Vortis with massive engines that brought it to the vicinity of Jupiter, within striking distance of his first goal, Earth.
The Zarbi Supremo was defeated when the First Doctor arrived on Vortis and, with the help of Gordon Hamilton, freed the crew of the Solar Queen, who then killed the Zarbi Supremo and returned control of the planet to the peaceful Menoptera. (PROSE: The Lair of Zarbi Supremo)