Gilles de Rais (1404-1440) was a Breton knight who fought alongside Joan of Arc against the English. He was hanged as a child serial killer.
He murdered a large number of children, possibly hundreds. During his trial, he confessed the true horror of his actions: he would sodomize the children, then decapitate, dismember and disembowel them. Even after death, their body parts were not safe from his sexual attentions.
It is a truly extraordinary character comparison for Max to make of himself.