Crusade, Book 4 of The Turner Chronicles

Three years after being named the Chin emperor Aaron Turner is busy building a new capital city and hiring archeologists, two endeavors he could happily pursue for the next several years. Unfortunately, his divided empire is close to war against itself, assassins are still trying to kill him, entire nations want his head, and a Talented prophet has declared a multinational religious crusade against him. Offsetting these threats are Aaron’s ill prepared army, inferior weapons, questionable generalship, and the insight of Delmac, a Clan savage from Isabella who has wanted to see Aaron dead for nearly twenty years.
What his enemies don’t know is that Aaron really is The One God’s Chosen, called Bringer, known as Death, and he’s become righteously pissed off.