As previously mentioned, William Afton committed a dozen murders in the 1980s. He established Fredbear’s Family Diner and Freddy Fazbear’s Pizza, where he assumed the guise of Spring Bonnie, a rabbit costume, to lure unsuspecting children into the restaurant’s backroom, where he murdered them in cold blood. Afton went to great lengths to conceal the bodies from law enforcement, presumably placing them inside the animatronic suits, thereby imprisoning their spirits within Freddy Fazbear, Bonnie, Chica, and Foxy.
Police never apprehended Afton for his crimes. However, after several failed business ventures, including Circus Baby’s Pizza World, the souls of his victims watched him die inside a malfunctioning Spring Bonnie costume, which tore his body into pieces. Although his corpse was left to decompose, his spirit refused to move on. Consequently, when a group of college students stumbled upon the suit years later and transferred it to a new horror attraction named Fazbear’s Fright, Afton continued his terrifying reign as Springtrap. Subsequently, he transformed into Scraptrap.
Otherwise, William Afton remains a mystery. He only appears as a tall, skinny man with glowing eyes, a wide smile, and a security badge pinned to his chest. “FNaF 2” implies that William experimented with a mysterious substance called Remnant, which traps human souls inside an inanimate object, thus explaining the supernatural nature of the animatronics.