Guardian Herd BK#3: Battle of The Skies

OMG I can't believe I'm writing book#3! I know the cover doesn't add up to Guardian Herd but it was the closest thing I could find as far as a white and black unicorn fighting. Nightfall has taken half of One Herd to form an army. He heads for Anok for reinforcements will the pegasi of Anok bow down to this black foal...