Testament of the Stars - Alexandra Beaumont - Bog

A fierce star-cult governs the lives of both the blessed from the plateau of Gemynd and the rebellious word-weavers of Rask. When Einya reluctantly joins the cult, she thinks only of the rights it will give her: the permission to marry her Raskian lover. Instead she is thrown onto a treacherous path of betrayal and political strife, and a battle for power.
Forced to drink the blood of the stars and steal their thoughts, Einya ends up at the heart of a fierce rebellion, caught between a fight for freedom and the twisted, alluring power of the stars.