The Temples Of Ayocan Book 14 in the Richard Blade series.
Sacred Murder!
Blade's newest adventure finds him in a bizarre and savage riverland. Its murky waters teem with ferocious man-eating creatures; giant batlike oranki dart from the dense jungles, looking for prey. And dead bodies carved with batwing symbols litter the streets of the city of Ayocan.
In Ayocan a religious cult as cruel as the land from which the people spring threatens the peace of this primitive civilization. Intended as their sacrifice, Blade escapes his captors and learns that the renegade priests have erected secret temples in the nearby kingdom of Gonsara. It looks as if Ayocan and Gonsara will soon be embroiled in a deadly struggle for power.
Disguised as a lay servant of this fantastic religious order, Blade plans to infiltrate the temples of Gonsara to find out what is really going on. But time is running out, and he and the other lay servants are being fed increasing doses of a drug which turns the into assassins for the cult.