Who is Sergeant Guy Challon from Sharpe's Christmas and what is their importance?

Sergeant Guy Challon is one of Lorcet's hussars. He is also one of the men holding Sharpe's family for ransom against Napoleon's gold. The Sargeant remembers Sharpe from the war, and when Sharpe leaves to retrieve the gold, Challon stays behind to guard Sharpe's family. While Sharpe is away, Challon attempts to rape Lucille. Fortunately, Sharpe catches him.