The Covenant of Shihala by Laya V. Smith and Kyro Dean

Synopsis:

For ten years, street musician Ayelet has been on the run from the faceless slave master who tormented her childhood. Every time she sees a wisp or the jewel-toned face of a djinn lurking in the shadows, she knows her tormentor is close and it is time to move on. Nobody else can see the wisps or the nightkeepers, so Ayelet must trust only in herself and her beloved lyre. Secretly, she longs for a home, but she knows anyone she gets close to will share in her terrible fate when the Faceless Man inevitably finds her. 

Jahmil Amir, djinn prince and heir to the throne of Shihala, has lost his army and with it his hope. The fierce drakonte riders are his only chance of retaking his fallen lands and avoiding an arranged marriage to the despicable queen of a neighboring kingdom. The desire for revenge has blackened his heart and stolen his sense of humor. Only when he hears music does Jahmil allow himself to dream of peace and to hope for a new home. 

When the prophecy of a traitor sends Jahmil into the human world in search of his lost cavalry, he finds Ayelet playing her lyre in the streets. She quickly plucks her way into his heart, while his diamond eyes tempt her with the dream of a real home. But the eight moons of Qaf harbor a different fate. A dark plan is unfolding that will open a rift between the human and djinn lands and unleash a power unknown in either world. To stop it, Ayelet must realize her tortured existence has forged her into an instrument of cataclysmic destruction. Meanwhile, Jahmil must let go of his thirst for vengeance and face the truth that love may be the only thing strong enough to save both of their worlds.