Alexander "Sawney" Bean(e) was the head of a 48-member clan in 16th-century Scotland, executed for the mass murder and cannibalization of over 30 to 40 people.
He began life as a hedger and ditcher, but, being prone to idleness and inclined towards dishonesty he ran away from home with a woman who was as viciously inclined as himself. Having no means to make a living they set up home in a sea cave in Galloway supporting themselves by robbing and murdering travelers and locals, and surviving on their victim's pickled and salted flesh. In time their family grew to an incestuous gang of 46 sons, daughters, grandsons and granddaughters.
http://en.wikipedia.org/wiki/Sawney_Bean
http://www.mysteriousbritain.co.uk/legends/sawney_bean.html
