According to Dr. Valack, the Beast of Gevaudan was formerly a human in the late 1700s, the time of the original massacre caused by werewolve attacks.
Gerard describes the tale of how Sebastien Valet, a French soldier in the 1760s. While escaping from British soldiers in Canada, he shifted into a werewolf after drinking rain water from the paw print of a wolf left after a shower of rain. This allowed him, through unexplained means, to transform into an enormous werewolf whose body is covered by smoke-like shadows.
Once the person became the Monster, there were many different descriptions of it. Witnesses allegedly described everything from a red-furred giant wolf to a cloven-hoofed panther how size is equivalent to a horse. According to The Argent Family lore, passed done by Gerad’s grandfather the Beast’s body was oil-black, yet solid but shapeless at the same time. It looked like a shadow pretending to be real.
Officially, the Beast is accused of murdering 113 people. According to the Dread Doctors, via Theo, the grave toll was closer to 500. During the time of the original incident that took place in Gevaudan, many people believed that the Beast solely killed for sport, as it never ate its victims and would only aim for head and neck of its prey. Sebastien’s best friend, Marcel, covered up sebastans crimes until Marie discovered the truth behind them.
The only weapon that historically demonstrated to be effective against the Beast was a steel pike handled by his sister, Marie-Jeanne Valet. The metal was formed from Wolfsbane, Mountain Ash and had been forged with her own blood beneath the light of a full moon.
After his death, Sebastien was completely erased from history by a Romain practice. His sister burned everything he signed and everything possession he owned in a manner known as Damnatio Memoriae.
Scott describes a similar incidence of this in reference to the Demon Tailor, a real world serial killer. He drew children into his shop in Paris where he would kill them, boil them and them eat their skin. The court ordered that all documents of the case be destroyed, thereby expunging his memory from history. The case Scott cites occurred in 1598, but he and Stiles link this narrative to the Beast as well.