Return of the Ebon Hand

Publisher's blurb:

The Cult of the Ebon hand, an evil group that worships deformity and mutation, has been rooted out and destroyed. Now, in Ptolus, even bearing a symbol of the Ebon Hand is a crime. There may be other chaos cults operating in the city, but the Ebon Hand, one of the worst, has been closed down.

Or so it was thought.
...
Suitable for 5e characters of roughly 6th level, or Cypher System characters of roughly third tier, and can be easily adjusted upward or downward in difficulty.