Perfect Match: The Dragon King - I T Lucas

To save his beloved kingdom from a devastating war, the Crown Prince of Trieste makes a deal with a witch that costs him half of his humanity and dooms him to an eternity of loneliness.
Now king, he's a fearsome cobalt-winged dragon by day and a short-tempered monarch by night. Not many are brave enough to serve in the palace of the brooding and volatile ruler, but Charlotte ignores the rumors and accepts a scribe position in court.
As the young scribe reawakens Bruce's frozen heart, all that stands in the way of their happiness is the witch's bargain. Outsmarting the evil hag will take cunning and courage, and Charlotte is just the right woman for the job.