Comes the Dragon - The Prophet Trilogy, #2

Alack and his surly mentor, Kol Abaddon, arrive in the Westland as slaves. But Kol Abaddon's powerful God cannot be enslaved, and when he thunders out on their behalf, they find themselves standing before the new emperor: Sabrus Caelius, the Sword of Heaven, an ambitious general whose sword is still wet with the blood of the king he has overthrown. Without question, this is the man Kol Abaddon has seen in his visions, the one who will bring judgment on the Sacred Land.
Alack, the shepherd boy who is becoming a prophet, would do anything to stop him--but it seems he may become the emperor's puppet instead. Meanwhile, Rechab continues to wear the title, riches, and power of Flora Laurentii. Heady as they are, Rechab only intends to make a new life for herself and then leave her newfound wealth behind. But when the plight of a village under the thumb of oppressive overlords comes to her attention, she is moved to use Flora's name to help.
It is what Flora would do, she is sure .