The setting is on top of a building
Protagonist- The Main Character
The Protagonist was the sniper. "A republican sniper lay watching. Beside him lay his rifle"
The Antagonist was the dude across from the sniper
Irony- The opposite of what you expect to happen
The Irony is that he waited all that time to kill that person then when he finally did it turned out to be his own brother. "The sniper turned over the dead body and looked into his brother's face"