Joseph Delon

 was a tour guide in the catacombs of Paris. He told the Fifth Doctor and Tina Drake about why human bones were used in its construction. He worked with the Cybermen to capture the Doctor. He had used the cover of the French revolution to bolster the Cyber ranks using the aristocrats who were to be executed. In his youth he contacted the Fifth and Tenth Doctor and told him that they had part of the Time Orb created by the Cybermen. He had some cyber technology implanted in him to help with his plans. After the Doctor went back in time to stop the Cybermen, he saw his father murdered by them which stopped them being able to control him as his emotions being heightened. (AUDIO: The Gates of Hell)