Scream of Stone

Scream of Stone by Philip Athans is the third book in the Watercourse trilogy.

"When the true mission of the Thayan Enclave is revealed, the richest man in Innarlith decides he wants to be the most powerful too, a once promising young man is transformed into a twisted undead assassin, and a quiet genius finally makes his stand, the explosive fury of decades of boiling rage explodes from the heart of a city at war with itself."