DRAMATIS PERSONAE
King Henry VI – King of England
Queen Margaret – Queen to Henry VI
Duke Humphrey of Gloucester – Henry VI's uncle and Lord Protector of England
Duchess Eleanor of Gloucester – Gloucester's wife
Cardinal Beaufort – Bishop of Winchester, Henry VI's great-uncle
William de la Pole – Marquis, later Duke, of Suffolk; lover of Queen Margaret
Humphrey, Duke of Gloucester was the youngest son of  Henry IV.  He has a small part in  2 Henry IV ,  but in this play he has a major role, acting as Protector of England. 
 
 Humphrey, Duke of Gloucester in a 15th century drawing. Image via  Wikipedia Commons.
Henry VI Part 2 Characters of the Play