What figurative language does Saki use in "The Interlopers"?

The narrator describes the wind as "whistling and skirling," comparing it, via metaphor, to the bagpipes. The action of skirling is most typically ascribed to this instrument. Further, the narrator says that the "restless beating" of the tree branches can be heard; this description personifies them, giving the branches the human characteristic of feeling restless. The narrator later personifies the storm by describing the sound it makes as a "fierce shriek." When Gradwitz and Znaeym are said to come "face to face" with one another, the narrator employs synecdoche: a figure of speech where a part of something is used to stand in for the whole thing; here, the men's faces stand in for their whole bodies. They literally meet each other in the woods; one man's disembodied face does not meet the other man's disembodied face. The narrator also says that neither man could bring himself to kill the other "in cold blood," a figure of speech; if someone is said to do something in cold blood, this means that they performed an action mercilessly and without feeling. This is an example of metonymy, where cold blood is being associated with a lack of feeling (as opposed to "hot blood" being associated with intense feeling).

Saki's narrator uses such figurative language as hyperbole or exaggeration when he describes the hatred between Ulrich and Georg, stating:

as boys they had thirsted for one another's blood

They don't literally want to drink each other's blood: the figurative language simply amplifies the emotional intensity their feud.

The story also uses the pathetic fallacy in which the ominous weather mirrors the feelings of a character in the story, in this case the heightened emotions of Ulrich as he:

wandered far down the steep slopes amid the wild tangle of undergrowth, peering through the tree trunks and listening through the whistling and skirling of the wind and the restless beating of the branches for sight and sound of the marauders.

The passage above uses imagery too, which is description using any of the five senses of sight, sound, touch, taste, and smell. We can see and hear the wild landscape.

Saki uses dialogue as well to show the reconciliation occurring between the two injured men. For example, Urich says:

We have quarrelled like devils all our lives over this stupid strip of forest, where the trees can't even stand upright in a breath of wind.

The quote above also uses the literary device of simile, a comparison using the words like or as, when Ulrich compares he and Georg to devils.

There are many literary devices in the story. 

First, there is personification. For instance, nature has a life of its own, and she is powerful. In fact, it is nature that pins them down underneath a tree where they have to face each other for a protracted period of time. Here is what the text says:

And before the moment of hesitation had given way to action, a deed of Nature’s own violence overwhelmed them both.

There is another personification of nature. The wind screeches as both men lay on the ground. Here is the text:

Ulrich was silent for a few minutes and lay listening to the weary screeching of the wind.

In terms of foreshadowing, there is a storm. This is usually a sign that something ominous will take place. It does, as the storm fells a tree, which pins both men down. 

There is also the use of irony. The Ulrich does not think he will meet Georg, but as he move around a tree, he is right there. The greater irony is that while both men are trying to survive under a tree, they actually reconcile; now they seek to outdo one another in generosity and kindness. The final twist of irony is that the story ends with wolves coming. One would think that something good would happen after their reconciliation, but it is just the opposite. 

There are many examples of figurative language. You can find personification in "and this wind-scourged winter night Ulrich had banded together his foresters to watch the dark forest." You can find metaphors in "Relief at being alive and exasperation at his captive plight brought a strange medley of pious thank-offerings and sharp curses to Ulrich's lips." (It isn't really a medley, right?) You can find non-literal language: "Good," snarled Georg, "good." (He doesn't really snarl.) You can find hyperbole: "How the whole region would stare and gabble if we rode into the market-square together."

What are some examples of hyperbole in "The Interlopers"?

When the author describes the history of the feud between the two families, he notes that Georg and Ulrich wish misfortune on one another. They have continued this inherited feud simply out of tradition and out of a continued personal ill will for one another. But it would be an exaggeration (hyperbole) to say that "they had thirsted for one another's blood." It is possible that their mutual hatred is so great that Georg and Ulrich both wish each other dead, but that does not mean they have an actual cannibalistic thirst for human blood. 

After they become trapped, Ulrich says his men are close behind and will arrive first. Georg says the same thing. Both men are being hyperbolic. Neither Georg nor Ulrich know how long it will be until either party reaches them: 

Both men spoke with the bitterness of possible defeat before them, for each knew that it might be long before his men would seek him out or find him; it was a bare matter of chance which party would arrive first on the scene. 

When Ulrich manages to get a drink of wine, it is described as a "heaven-sent draft." It only seems this good because he is in such a dire predicament and it serves to calm his nerves. Their reconciliation is "dramatic" but this is a fitting description and not really an exaggeration. 

What is a metaphor in “The Interlopers”?

A metaphor is a comparison of two unalike things, where one is said to be the other. In the very first paragraph, the narrator uses a simile to compare Ulrich von Gradwitz’s behavior to one who is on the hunt for some “beast” in the forest. The next sentence contains a metaphor in which Georg Znaeym is compared to the “game” for which Ulrich hunts:

The game for whose presence he kept so keen an outlook was none that figured in the sportsman’s calendar as lawful and proper for the chase.

People are not game, and it is not legal to hunt people. “Game” typically refers to deer, rabbits, or some other wild animal that hunters would pursue in order to put meat on their tables. The choice of this metaphor conveys just how little Ulrich thinks of Georg, that he is compared to an animal.

The narrator uses another metaphor to describe the sound the storm makes when lightning strikes the tree that falls upon the two men. It is called a “fierce shriek,” but storms cannot shriek, and so we understand that the description is figurative. Some sound made by the wind or perhaps lightning or thunder is compared to a humanlike shriek in this metaphor, perhaps assisting readers to recognize that nature is the true antagonist of the story.