Dark Skies by Danielle L. Jensen

A RUNAWAY WITH A HIDDEN PAST
Lydia is a scholar, but books are her downfall when she meddles in the plots of the most powerful man in the Celendor Empire. Her life in danger, she flees west to the far side of the Endless Seas and finds herself entangled in a foreign war where her burgeoning powers are sought by both sides.

A COMMANDER IN DISGRACE
Killian is Marked by the God of War, but his gifts fail him when the realm under the dominion of the Corrupter invades Mudamora. Disgraced, he swears his sword to the kingdom’s only hope: the crown princess. But the choice sees him caught up in a web of political intrigue that will put his oath – and his heart – to the test.

A KINGDOM UNDER SIEGE
With Mudamora falling beneath the armies of the Corrupter, Lydia and Killian strike a bargain to save those they love most—but it is a bargain with unintended and disastrous consequences. Truths are revealed, birthrights claimed, and loyalties questioned—all while a menace deadlier and more far-reaching than they realize sweeps across the world.