Roget

According to the Fourth Doctor, Roget was an "overenthusiastic student". He was Cilia's boyfriend.

Roget studied the Jewel of Fawton. He realised that the Jewel's complicated structures inside meant it was a hive mind for crystalline creatures, and it left the creature stuck in a state of hibernation indefinitely while it existed as a museum exhibit. Roget stole the Jewel and placed it in its original location, re-awakening the creatures, who were the Jewel of Fawton's rightful owners. (COMIC: Prisoners of Time)