Monsters
People
In other words, people you'd probably feel bad for fighting.
Yule cultist
Christmas elf
Unjolly elf
Beasts
All manner of critters that might want to enjoy a Christmas elf snack.
Feral reindeer
Kracken spawn
Children of the terrifying Kracken that terrorizes the ocean between the Arctic Archipelago and Greenland.
Christmas Entities
Creatures of the North Pole.