WWI was a complicated and drawn-out war. It was the eruption of many different inter- and intra-national conflicts which drew on and on. These conflicts led to devastating losses for all of the parties involved. Many countries and regions formed alliances with others and fought on multiple fronts; the war lasted for just over four years and involved a series of crises all around the world. The opening passage of The Interlopers goes into detail about ongoing disputes about a very small piece of land; this is similar to the political backdrop of WWI.

One of the enduring traumas of WWI was trench warfare. The Western Front was one of the main battle areas and the lines hardly moved for two years despite being the site of millions of deaths. The men fighting against each other in the trenches were so close to their enemies but had no control over the battles; this is similar to the conversation between Georg and Ulrich while they are pinned under the trees. The two men eventually call a truce with each other, giving in to their humanity. They put aside their petty quarrels about land—their old feuds—and decide to form peace and show it to the villagers. Georg and Ulrich imagine the bright future that they have together, talking about feasting and how, if they are allied, there will be “none other to interfere, no interlopers from outside.” This positivity and hope for the future is dashed when they see that it is not their men who come for them, but wolves.

The wolves, in this case, can be seen as a metaphor for the technology of war. The technology used in WWI was unprecedented: poison gas and tanks in particular cannot be reasoned with like another human in close combat. Just as there is no way to negotiate with a canister of poison gas tossed into a trench, there is no way to negotiate with wolves.

This is a brilliant question. Let us remember that this short story was published in 1919 just after the end of World War One, and obviously we can expect Saki's literature to have been impacted greatly by this seismic historical event. What I find interesting is the way that we can view this short story as an allegory about the futility of war and discord between humans. Let us remember that the beginning of the story paints an incredibly depressing picture about the capacity of humans to cling on to feuds even when the cause is slight:

The forest lands of Gradwitz were of wide extent and well stocked with game; the narrow strip of precipitous woodland that lay on its outskirt was not remarkable for the game it harboured or the shooting it afforded, but it was the most jealously guarded of all its ownder's territorial possessions.

Even though the land is almost worthless, still Gregor and Ulrich are prepared to kill each other to own it. We can perhaps see their feuding as an allegory of the two different sides of the war. Both fight viciously and tenaciously for little reason. The story gives us a grim and ironic warning by showing the way in which Gregor and Ulrich become friends, but only when it is too late, for nature and the world seems to have tired of this feud that is being fought over land, and has acted itself to end the feud in its own way. The message of this story seems to be, that if we devote ourselves to hating another human, we ultimately cause our own extinction and demise.