Valley of Shadows. Heir to the Firstborn, #7

When the Heir to the Firstborn is chosen by the Mother, the lore dictates that they must find their Companions among the tribes, and the first of those shall be Water. But when Aeris, oldest daughter and Heir to Firstborn Aria makes her Progress, her Water is nowhere to be found. The lore has once more been broken, threatening to throw the world out of balance. Two years later, as Aeris comes of age and continues to seek her missing Companion, an urgent summons from the Temple brings the Firstborn and her Court to the mountains.
There, Aeris will come face to face with an enemy who has been waiting for her since her birth - a man known only as Dark.  Separated from her Companions, Aeris has only one ally standing between her and the darkness that wants to possess her - a Water warrior who has never seen the sea.