From publisher blurb:
The War That Saved Christmas!
Everyone knows the story of Santa Claus, but before he could become the jolly gift-giver we know and love, Frank L. Baum (author of the Oz series) wrote a tale of a fantastic battle between Good and Evil, waged between the Immortals and the Awgwas.
Detailed in this supplement are the five monstrous armies led by the Awgwas (the Awgwas themselves, fire-breathing Asiatic dragons, towering Tartary giants, pitch-black Patalonia demons, and vicious goozzle-goblins) and the four Immortal races who opposed them (powerful fairies, crooked knooks, childlike ryls, and beautiful wood nymphs). Also included are rules for playing the four Immortal races as PCs.
This PDF has a bookmarked table of contents and features monsters with challenge ratings ranging from 1/4 to 8.