If I were the devil and was trying to imple-ment a plan to destroy any individual parish, I would concentrate my efforts in two main areas. Perhaps a current version would read something like this Master of Darkness, the parish you have assigned me to is very strong against us. Many people pray and there is a sense of, if you will pardon the expression, Good surrounding the whole property. I don't seem to be having much luck in tempting the people with all the normal wonderful temp-tations like lust, greed, and power. The Master of Darkness looks balefully at his underling and snorts a reply.
Human creatures are all the same.
They have no imagination and are basically lazy. The methods used in past campaigns will have this parish in ruins very quickly. You must not let any of them know that you are present. Instead, use their own apathy and self-righteousness against them. Mount your attack in two areas and you will destroy them.