Who is Duke Roger of Conte from In the Hand of the Goddess and what is their importance?

Duke Roger of Conte is Jonathan's older cousin. He is also the heir to the throne if something should happen to the prince. Roger is the most powerful sorcerer in the Realm, and he doesn't hesitate to use magic in his attempts to kill "Alan," the Prince and the Queen. He also leads the army against Tusaine, and he genuinely seems to be the model commander and Duke. This image is caused by the veiling spell he has cast over the Court, so no one could see his intent to kill the royal family and steal the throne.