The adventurers invested rumours of a suspicious mine, only to encounter a terrible dracolich when they first attempted to enter the mine. Although victorious in the battle, pulling the beat out of the mine had badly destabalized it, causing the entrance to collapse as the adventurers barely escaped along with the corpse of the man who raised it.
The corpse later turned out to be Luther, a prominent priest of Pelor. Following his trails revealed a string of personal contacts who Luther had driven to madness by encouraging them to push their magical arts to dangers extremes, due to an unnamed looming threat.
These extremes included a calzone golem, a town compelled to walk into the sea, and a town torn to shreds by the walking undead.
Whatever had convinced Luther and his associates, marked by a mysterious white hand, to abandon their morals and their god must be a terrible threat indeed.