I loved this book! It's the story of an ambitious dragon who might be destined for evil. It seems like it's for older kids than the Wings of Fire: Original Series.

 

Publisher's description:

Long before the SandWing and the Dragonet Prophecy, Darkstalker, half NightWing and half IceWing, is hatched under the three moons--born into a divided heritage, he is destined to become the most powerful and dangerous dragon Pyrrhia will ever know, and it will take the combined efforts of a SeaWing named Fatham and a NightWing seer named Clearsight to come up with a way to save all the kingdoms from his anger.