In Teen Wolf, why was Sebastian Valet (The Beast of Gevaudan) so powerful? 1 Answer. Quora User, Acquired knowledge from multiple areas. How do you create the ultimate werewolf? That was the question that Teen Wolf showrunner Jeff Davis faced when he decided that The Beast. The Beast's spirit is placed inside a host, Mason Hewitt which transforms into Sebastien's werewolf form. The now-undead Beast only reverts back into Mason and. La Bête du Gévaudan, also known as The Beast of Gevaudan, is a monstrous Werewolf who terrorized France in the s. The Beast was eventually killed by.