The French mage known as LeDuc was the master of the burgeoning Paris chantry of the House Tremere. He was one of the closest advisors of Tremere himself, and was among the seven original mages transformed into vampires by Goratrix's ritual.
LeDuc took Etrius' part when rivalry began to grow between the Swede and Goratrix, but was also present in other key events of Tremere history such as the Diablerie of Saulot. However, around 1133, the Frenchman was commanded by his master to leave the Parisian chantry and travel to the Levant to pursue matters of importance to the clan (apparently, he would hunt Salubri and their secrets).
Goratrix would step down as Lord of Ceoris and head to France, to take over LeDuc's place as leader of the Parisian hall.