What is the role and significance of Stanhope in the play Journey's End?

Stanhope is the protagonist of the play. After joining the war straight out of school at eighteen, he has served three years by the time the play begins, having risen to the position of Commanding Officer of C Company. Stanhope drinks heavily to deaden his nerves in order to cope with the brutal reality of war. Though his temper fluctuates wildly, he is liked and respected by his men. Stanhope is engaged to Raleigh's sister, who he hopes will continue to believe that he is a hero. Stanhope is characterized as large and handsome.