A fast paced all in one novel by one of my favorite light authors.

The main character is a kobold, a previously tunnel dwelling canine humanoid, who works for an evil-and-a-bit-insane powerful wizard as general castle maintenance staff that find herself thrust in to a complex situation that can't be handled by simple polishing, cleaning or organizing stuff.

Its a castle filled with cursed heroes and mages, many transformed into animals or inanimate but vocally communicating objects, as well as a few frog princes and the like. All are waiting for the death of the Wizard when his curses will end...
and some have murder in mind to help speed things along.

The plot and setting throw a lot of classic fantasy story tropes on end and juggles them in amazing new ways. A great book to read if you're stuck with a long commute on a plane or train.