Retribution — T.C. McMullen

When Aiden Devassi with his brother, Blaine, and cousin, Rylan Brye Annis, spot a Pure One's air ship on the tail of an unknown craft, the three do what they do best, never expecting to start the war for the end of all things on Earth. They also never expect it when they are told to continue training while other troops go out to the borders, borders, Aiden soon discovers, constantly under vicious attack. It doesn't take long for Aiden and Blaine along with Rylan and his sister, Taite, to decide they need to act against the wishes of their Greatmothers. Then little sister Shani, realizing the others are gone, attempts to set out on her own to meet them. What she finds is a brave watcher and horsemaster willing to join her and monsters intent on tearing them apart. The Brye Annis siblings along with their cousins will discover just how important they are in the new war where the Pure Ones are intent only on complete annihilation.