In the exposition to O'Flaherty's "The Sniper," the main character is physically described in a way that reflects the story's setting.
The sniper's physical condition reflects a wartime reality. In this civil war, resources such as food are limited. The sniper mirrors this with his "thin and ascetic" appearance. Such a description enhances how the sniper has forgone "luxuries" like eating in favor of the focus he carries towards his mission. As the sniper is being described, it is clear that "he had eaten nothing since morning," underscoring a gaunt condition so often a part of war.
The sniper's primary motivation helps to enhance his physical dimension. O'Flaherty describes his eyes as possessing "the cold gleam of the fanatic," and that he was "too excited" at what he set out to do. This political and military focus is underscored through his "deep and thoughtful eyes." There is a seriousness to the physical appearance of the sniper, for he is "used to looking at death." From his initial description, it is clear that the sum total of the sniper's being is being channeled into the accomplishment of the mission at hand.
Such a physical description shows a man who has nothing else on his mind but what he has set out to do. O'Flaherty enhances this with a physical description that leaves little room for anything else in the sniper's life other than victory in war.