Temple of Corruption

From the introduction:

The prophet of a diseased god plagued the local city for years. He was eventually caught and executed, but his body was recovered by his supporters and spirited away into a swamp south of the city where with the help of their wererat allies, the priesthood built a temple complex. The priesthood now captures travelers on the southern road to the city for their diseased experiments. Their ultimate goal is to raise their fallen prophet as a Zombie Lord who they believe will spread the diseased god’s corruption throughout the land.