Zentor was a scientist who set up a base on the Haunted Planet. He created the legends about the world to keep people away while he developed a gas capable of poisoning the atmospheres of all of the planets in the universe, after which he would demand a ransom from everybody. When the First Doctor, John and Gillian made their way into Zentor's castle, he captured them, told them his plan, then tried to kill them for knowing too much. He put them in a machine which fired atomising rays, but the Doctor used Gillian's mirror to reflect the rays back. He then pretended to be his own ghost and threatened to haunt Zentor. Frightened, Zentor fled out of the castle and into the marsh outside, where he drowned. (COMIC: The Haunted Planet)