The Dire Druids of Delver's Deep

From the introduction:

Delver's Deep is a well known adventure location. In recent months, some mysterious druids have occupied The Deep, as it is known to locals. This order of druids wear black robes, and their tight lips have led to rumors and gossip about their real nature and purpose. It is “common knowledge” that they are an evil cult practicing human sacrifice. Like most villagers, they mind their business, hoping that is enough to protect them; yet are glad to take the coins from selling supplies to the druids.