The short story "The Interlopers" uses many basic literary devices. It sets up characterization, motive, allusion, all taking place in a symbolic setting. However, the central most literary device that is used would have to be that of irony.
Irony is the most important literary device being used because that is what the ending is all about. The two characters move through an incredible emotional journey as they lay physically trapped under the tree. The start out wanting nothing more than to kill each other. However, after being trapped, they end their feud and become friends. The ironic ending where they see "figures" running down the hill toward them elicits excitement for their rescue, then the last word "wolves" leaves you with dark humorous irony that lingers after the story is finished.