Five ​Dark Fates by Kendare Blake 

After the grim confrontation with Queen Katharine, the rebellion lies in tatters. Jules’s legion curse has been unbound, and it is up to Arsinoe to find a cure, even as the responsibility of stopping the ravaging mist lies heavy on her shoulders, and her shoulders alone. Mirabella has disappeared.

Katharine’s reign remains intact—for now. When Mirabella arrives, seemingly under a banner of truce, Katharine begins to yearn for the closeness that Mirabella and Arsinoe share. But as the two circle each other, the dead queens hiss caution—Mirabella is not to be trusted.