Deceit and Darkness (Celestial Whispers #2) by Jeannin Counts:
 
The stars have fallen. With war on the horizon, the only way out is through death itself.

The stars’ conquest is in full force, and their leader, Rigil, will stop at nothing to subjugate all of humanity. In the midst of their grief, Iyana and her companions must turn to the gods for guidance, and they’re not all welcoming to mortals.

Only the first Aztia can teach Iyana how to banish the stars once again. But the only way to reach her is to send an emissary to the afterlife, and there’s no guarantee the gods won’t get to them first.

Meanwhile, Rigil’s reign of terror is only spreading, and he’s hells-bent on ending any chance of retribution. When Altair is tasked with hunting Iyana down, his loyalties are put to the ultimate test. As intense as ever, he’s no one’s slave. But what does that mean when he’s commanded to kill his former lover?

An unforeseen ally. A willing sacrifice. A voyage into the unknown.
Can destiny overcome deceit? Or will humanity fall next?