Who is Major Warren Dunnett from Sharpe's Rifles: Richard Sharpe and the French Invasion of Galicia, January 1809 and what is their importance?

Major Warren Dunnett is described as an inept officer, who hates Richard Sharpe. Dunnett assigns Sharpe the duties of quartermaster because he doesn't see him as capable of leading men. He resents Sharpe's quick rise the ranks and is jealous of his record of bravery. Unfortunately, Dunnett's incompetence is ultimately responsible for separating the riflemen from the rest of the British Army.