Shadow and Flame. The Imperial Chronicles, #3

The Empire has reached its zenith of power and prosperity, but things are rarely as they seem... As shadow spreads across the world, the Revered Order of Hunters scours the provinces for demon shrines and their fiendish worshipers, all while an eerie silence south of the Imperial border hints of a gathering storm. The emperor Severus struggles to maintain the recent peace and harmony, though he knows the growing dark touches all strata of society, from the highest official to the lowliest street actor, and no one is worthy of trust.
Far away, unbeknownst to the southron King of Kings and the Imperial government, the brother-sister heirs to the Red Throne of Haroon lay in hiding. But as a dark faith spreads by the sword across the Southern World, plunging ancient nations into chaos, not even well-born monarchs will escape these trials of SHADOW AND FLAME.