The Temptation of Asphodel

The game of the gods is speeding up, and when Tamsen and Brial find a long-lost civilization of Elves, the pattern of the gods' game starts to become clearer. After a new magic evens up the odds of the foreordained battle, Tamsen begins to feel confident—until a lethal and forbidden possibility tempts her from her path. 

But that possibility is actually the opening gambit of an ancient, dangerous deity--a gambit that signals the emergence of a new foe into the game. 
When Tamsen is drawn into conflict with immortal enemies, she discovers that the line between obedience and temptation is much narrower than she thought.

Obedience is dangerous; temptation can kill.