Vol Mercurius was a human who lived during the 26th century.
He owned the planet Dispater, having bought it with money he had stolen from Abslom Daak. He only had the robot Klikbrain as a companion. Daak went to Dispater to recruit Mercurius to fight the Daleks. They were invading the planet when Daak arrived, which helped convince Mercurius to depart on the Kill-Wagon. He left Klikbrain on Dispater. (COMIC: Star Tigers, Nemesis of the Daleks)