City of Burning Wings. The Warrior of Ashes

The young warrior May has spent her entire life preparing to ascend the throne of ashes as the successor to the king. She's the fastest sky stormer the floating city of Elydor has ever seen. But when the king dies, the mark of the ruler does not appear on her; instead, it's on the forehead of the mysterious dealer of secrets, Luan, from the slums. And May, of all people, is supposed to help him learn to use his newly-gained power. She obeys – reluctantly, until she realizes that not only the lives of the two of  them depend on it, but the future of all Elydor.