The worldbuilding at the front conveys a lot of texture to help flesh out the narrator and the Copperclaws in a quick, focused set of words. The meat of the story does a wonderful job oscillating between the grimness of the situation Skittles is trying to undermine and the absurd humor of the monastic order. I think it works especially well that the humor is non-diegetic, and that the silliness of monastic rats chanting "Holy Funk Hunk" is treated deadly serious within the universe. These monks are zealots and the Copperclaws have struck a deal with a ratty devil.
Skittles' attempt to argue against the use of what is essentially a WMD manages an interesting complexity as it encompasses a broad-morality ("killing civilians is wrong") and a personal grievance ("these rats are our enemies"). Our little hero's noble sacrifice was well foreshadowed and the closing is very sweet.