Roger du Plessis is the father of Alex du Plessis.
Roger and Johan's father was abusive towards Johan when he realised that Johan had Savant abilities. He encouraged Roger to treat Johan badly.
With his family, they live between Florence and Misty Falls.
Roger is shocked to discover that his beloved wife, Miriam, is a Savant.
Although Roger participated or did not help Johan during their childhood, he seems to have been brainwashed by his father to hate Savants. He has tried to pass this trait onto his son, Jason, which hasn't been as successful.
Roger looks similar to Alex, his eldest son.