A good concept for an unconventional enemy requiring unconventional weapons to defeat, and nicely well-written into the bargain. I always appreciate when writers can slip in worldbuilding in both subtle and convincing ways, and you manage both. The only thing I'd call out is the titular Problem With Elves doesn't seem to have much bearing on the story as a whole; the Archon's people just vanish halfway through and don't do anything at all of note. But overall nicely done with an effective cliffhanger ending.