Christopher Dalliard

 was an acquaintance of Sieur d'Eon. He was hosting a costume party when the Tenth Doctor and Rose Tyler came to his house in 1791. He introduced the Doctor as Luigi Barver and expected him to perform an aria. He was secretly helping Hempel and Joxer to trap and enslave his guests. He was later killed by his employers when his usefulness has come to an end. (AUDIO: The Sword of the Chevalier)