The protagonist in Liam O'Flaherty's "The Sniper" clearly demonstrates a gradual change from fanatic to sensitive human being. Clearly, the sniper is fanatic at the beginning of the story as the narrator states this explicitly.
His face was the face of a student, thin and ascetic, but his eyes had the cold gleam of the fanatic. They were deep and thoughtful, the eyes of a man who is used to looking at death.
The sniper's eyes show us a man who has become a fanatic, intent only upon killing those who wish to do him harm and obsessed with his cause. Even eating was forgotten due to the excitement of battle.
When the sniper sees an enemy vehicle pull up, he is still demonstrating fanatical behavior. He shoots the enemy sodier when a turret opens on the vehicle, and then he shoots the old woman who had pointed out his location to the soldiers in the car. The sniper feels no emotion whatsoever when he does this, or the narrator does not mention any emotion. These are merely enemies, and he is simply carrying out his duty.
The sniper exhibits the qualities of a sensitive human being only after he has shot the sniper on the other rooftop.
The sniper looked at his enemy falling and he shuddered. The lust of battle died in him. He became bitten by remorse. The sweat stood out in beads on his forehead. Weakened by his wound and the long summer day of fasting and watching on the roof, he revolted from the sight of the shattered mass of his dead enemy. His teeth chattered, he began to gibber to himself, cursing the war, cursing himself, cursing everybody.
The sniper is truly sickened by this image and later throws his revolver down in disgust, and the fact it almost kills him when it goes off seems to bring him back to his less sensitive self. However, the last line of the story certainly ensures the reader that the sniper will once again feel the same disgust he felt earlier.