Blood of the Prophet (Fourth Element Series #2)

Visionary. Alchemist. Savior. Saint. The Prophet Zarathustra has been called many things. Now he spends his time drawing pictures of weird-looking goats. That's what happens when you've been stuck in a prison cell for two hundred years. But the man who might be mad, and is definitely supposed to be dead, has suddenly become very valuable again. It's only been a few weeks since Nazafareen escaped the King's dungeons with her daeva, Darius. She hoped never to set foot in the empire again, but...