Who is Bran de Montfort from Falls the Shadow and what is their importance?

Bran de Montfort is Simon's second son. He enjoys drinking and socializing, something that will eventually lead to his downfall. When Simon grants his son leadership of the army, he fails to meet him in the battle against Edward, deciding that a few days of rest and relaxation were warranted. As a result, Edward attacks Bran's army disperses his men, and in the end..... defeats Simon.