This passage from the History of the Church of Neroth seems to bear on the situation developing in Nishanpur:
And in those days the Decayed Master of Pestilence sent visions to his faithful. The world had become corrupt and distant from the true worship of Neroth. Purification was needed and the Decayed Master of Pestilence provided the inspiration to his most faithful servants. As the world was deep in corruption, so corruption would purify it. All manner of plagues and afflictions would be granted to his faithful and they were instructed to spread them across the land. As the unfaithful suffered so they would be purified and at the moment of death ascend to the Paradise of the Gods and join the Lord of the Dead and the throngs of the faithful.
This passage corroborates what the official church history reveals:
Our interrogations of these heretics reveal a disturbing picture. They believe that death from disease purges the soul of its earthly corruption and leaves it free to ascend to the Paradise of the Gods. They sincerely believe they are doing their God’s work, and that the plagues they spread are a gift from Neroth. They cannot be persuaded otherwise through any means at our disposal. Our current instructions are to desist from attempting their redemption and focus on stopping the spread of these damnable plagues of theirs.