I had some issues with the ultra toxic masculinity of the main plot, but Krampus is the star of this novel and he's totally worth sticking it out for the whole story. Not everything is as it appears, and the norse myths sprinkled within are almost as delightful as the voice of Krampus (holy Hel- sorry not sorry).
Characters often screaming "Fuuuuck!" was a little tough though and pulled me out of the story each time; it's something about the screaming, not the word choice.