Emerald Lindstrom

 was the Daughter of an Earth scientist whose employers wanted to use as a weapon. She came to Draconia to find help saying that she didn't want the weapon built. She went with the Third Doctor to find the source of the weapon. She tortured the Doctor to get scientific information from him using a mind probe, which she managed. Using this information she went to create the weapon. so that she could create an empire for Intrastellar Minerals. (AUDIO: Conspiracy in Space)