It's hard to describe Elizabeth Bathory's malevolence. But summed up in a word, it'd probably be a single, drawn-out, blood-curdling scream. Known as the Blood Countess, Bathory was born in 1560 in Transylvania to a family of Hungarian/Transylvanian nobility. Her uncle had been the King of Hungary, and her cousin Stephen Bathory was the Duke of Transylvania. At age 15, Bathory married Count Ferencz Nadasdy, a man affectionately known as the "Black Knight of Hungary." He was often out on business trips (a.k.a. war), and Bathory would ask for details of his gory accounts in letters. Allegedly, Bathory spent her downtime torturing and murdering peasants around her while he was away, sometimes with the help of of elderly female accomplices.
And now (warning!) the moment you've all been waiting for—a small sampling of the downright despicable acts Bathory allegedly perpetrated upon her victims, as reported by Rejected Princesses:
Beat them to the point where there was so much blood on the walls and beds that it had to be soaked up with ashes and cinder
Pricked their mouths and fingernails with needles and cut their hands, lips, and noses with scissors
Had them stand outside in tubs of ice water up to their necks until they died
If you're twisted, there are plenty of other, more gruesome examples here.