Queen of Legends and Lies by Nina Frost

The gears of destiny have been set in motion.
Lark Axton has failed.
Failed to save Flighthaven, the military school she attended before she knew she was a dragoncaller and the descendant of the true royal house of Tirene. Failed to kill King Xenon and stop his army of the drachen, who are taking over the world by stealing the free will of its people at the bidding of the mad god Narc. Worst of all, she failed to save Sterling: the Crown Prince Knox of Tirene, her perfect match, the cold to her fire, the man she loves…
And now, the enemy who wants to kill her.
With Sterling corrupted by the drachen, Lark—the only dragoncaller in world—will become queen. As the kingdom crumbles, the council is determined to keep Lark safe. However, a thread still connects Lark and Sterling, and she refuses to give up on him. The fate of the world rests on her shoulders, and she must somehow save Sterling, the dragons, and the kingdom before it’s too late.
Danger lurks in the shadows, and with enemies closing in and time running out, there’s only one option. She must defeat Narc once and for all, before the vengeful god destroys her first.