Cannibalistic cult of '40 incestuous family members in a cave and ate passers-by

[serendipity]

.
Nothing much has changed then!

Alexander "Sawney" Bean and Black Agnes Douglas led an incestuous cult of 40-plus members in the 16th Century.

https://www.express.co.uk/news/uk/1739560/Dark-legend-Sawney-Bean-cannibalist-incest-Scotland