The Murderous Nobleman
The person most likely to have been working with the devil out of everyone on this list was Gilles the Rais because of how horrible his crimes were and how clear-cut his depravity was. The aristocrat Gilles de Rais, who was first celebrated as a hero of France for his participation in the Hundred Years' War—during which he fought with Joan of Arc—lived a hidden and horrifying second life in which he delighted in torturing and killing children.
De Rais was apprehended in September 1440 after a murdering rampage that lasted almost ten years and may have claimed over 140 people. De Rais and several of his subordinates and accomplices both admitted to their heinous crimes during his trial, however these admissions were obtained by torture.
In addition to the killings, Gilles de Rais acknowledged practicing Satanism by constantly calling upon the devil and his demonic henchmen. The aristocrat offered the blood and organs of his victims in exchange for knowledge and control over the dark arts, but he refused to sell his soul.
Gilles de Rais was labeled "a heretic, an apostate, a sorcerer, a sodomite, an evoker of evil spirits, a diviner, a murderer of innocent children, a criminal, a backslider and an idolater who has diverged from the religion and who is illy disposed of it," by the inquisitors who oversaw the trial. Unsurprisingly, he was put to death for his crimes, albeit there are still unanswered issues about his guilt.
