Kai Tobias

 was part of a community on Phobos. He told Amy and Farl about the Phobian's. He wanted people to get no longer travel to Phobos. He told the Eighth Doctor his stories. He enticed peoples fears. He created the being that was terrorizing the populace. He wanted to kill the Doctor and Lucie Miller by throwing them down the wormhole. (AUDIO: Phobos)