This Ends in Embers — Kamilah Cole

Perfect for fans of Raybearer and Fourth Wing, this astonishing sequel to the bestselling novel So Let Them Burn doesn't hold back. After all, there are no easy endings in war -- especially when sisters are forced to fight on opposite sides.
 
Faron Vincent was once the saint of San Irie. Now, she's done the unthinkable: betrayed her country. Alone, disgraced, and kidnapped, Faron is forced to help Iya grow his bloody empire. With her soul bonded to a ruthless killer, Faron has become an enemy to her people… and she fears they might be right.
 
Elara Vincent -- the new Empyrean -- must undo the damage her sister has caused. San Irie has been brought back to the brink of war as Iya proclaims no nation will be safe from his brutal invasion. But how can Elara save her sister, her best friend, her country, and her world when she's already cracking under the pressure?
 
This heart-pounding conclusion to the Divine Traitors duology pushes these unforgettable heroines to their breaking point and beyond. Because when the lines between hero and villain are blurred, deadly sacrifices must be made.