The Snow Queen's Shadow by Jim C. Hines (Princess #4)

From Goodreads:
A broken mirror. A stolen child. A final mission to try to stop an enemy they never dreamed they would face.

When a spell gone wrong shatters Snow White's enchanted mirror, a demon escapes into the world. The demon's magic distorts the vision of all it touches, showing them only ugliness and hate. It is a power that turns even friends and lovers into mortal foes, one that will threaten humans and fairies alike.

And the first to fall under the demon's power is the princess, Snow White..

The last of the Princess series! I am sad about that. It was an excellent book and a great ending to the series. It really explores and twists the story of the Snow Queen.  All the elements are there from the story by Hans Christian Andersen, just remade to fit the story of Snow's possession of the demon who inhabited her mother's magic mirror and that demon's quest for power and Snow's desire for revenge. It was really well done how Hines managed to have the Snow Queen's story and yet make it about Snow White and fit the narrative of the series as a whole. I enjoyed how Talia and Danielle fit into the story and the exploration of Snow's past. She was the only princess prior to this book whose back story hadn't been fleshed out more and this book filled in that gap. There was a lot of action and definitely a lot of emotion. It was a good read and I am going to miss this series.

Princess
The Stepsister Scheme (#1)
The Mermaid's Madness (#2)
 Red Hood's Revenge (#3)