Earth's End (Air Awakens #3) by Elise Kova

A woman awoken in air, a soldier forged by fire, a weapon risen from blood.

Vhalla Yarl has made it to the warfront in the North. Forged by blood and fire, she has steeled her heart for the final battle of the Solaris Empire’s conquest. The choices before Vhalla are no longer servitude or freedom, they are servitude or death. The stakes have never been higher as the Emperor maintains his iron grip on her fate, holding everything Vhalla still has left to lose in the balance.