The Sorcerer and the Shaman (Sorcerer Chronicles, #4)

The Sorcerer Gaumata has lost the Throne of Persia to the true king, Darius. He has also lost his own body, but it is still going well. He has managed to possess Mihr, son of the powerful sorcerers Rustem and Anahita. He should have known they would retaliate. Not only have they now forced him to give up his beautiful, new vessel, but they also forced him into the vile body of a fly. As if this were not insult enough, Gaumata learns that they have managed to save their unborn baby, Antiochu...