Valmont was the name assumed by a Player whilst on Earth.
He worked with the Countess to help Napoleon Bonaparte win the Napoleonic Wars. He was unused to physical combat, so when Colonel Grant challenged him to a duel, he fled back to the realm of the Players. (PROSE: Players)
His attempt to assassinate the Duke of Wellington prior to the Battle of Waterloo was thwarted when the Time Lady Serena threw herself in front of his shot, killing her instantly; during a later confrontation with Valmont, the Doctor's grief over her death was so intense that he found it easy to allow a duel to take place with Serena's killer despite his usual distaste for violence.