Dark Djinn (The Darkness of Djinn Book 1)

Duplicity and deception: aid from a djinn is a curse under any guise.
Betrothed to a cruel lord, Princess Kordahla dreams of fleeing to her decadent neighbour, a journey fraught with danger, and no promise of sanctuary at its end. Her one hope is to offer the southern shah a prize so valuable he cannot refuse to harbour her: the secret of the mahktashaan, the soldier-magicians sworn to protect her father’s court.
But the mahktashaan guard their magic with blooded sword, and in stealing one of their powerful crystals she will risk her life. Unless she accepts the help of a treacherous djinn intent on tricking her into a deal.
It is a compact which threatens to shatter the fragile peace in the Three Realms.

A gripping tale of realms besieged and honour lost, of blood-ties severed and romance dreamed, Dark Djinn begins an epic quest to save mortals from the schemes of djinn.