Intro. Cassidy was one of the first victims of William Afton. He killed her, along with four other children, in the 80s, but the girl's soul did not calm down. And she took possession of the animatronic Golden Freddy and became a vengeful spirit. (Events between the 1st and 3rd fnaf, ending): When William Afton broke the animatronics Freddy, Bonnie, Chika, and Foxy, which contained the ghosts of the remaining murdered children, and Cassidy was at the head, they together drove Afton into a secret room in the pizzeria, which contains Springbonny's costume, and William Afton climbed into it in the hope of hiding from them, but the springs of the bone collapsed and pierced Afton's body, and after 15 - 30 years, he came to life and became Springtrap. (End of events of fnaf 6 "pizzeria simulator"): Where Scrap Baby, Molten Freddy, Lefty, and Skpattrap (formerly Springtrap) all burn and retire, but William Afton is trapped in his personal personal Hell created by Cassidy herself, who wanted him to suffer forever in his personal Hell.
(You are William Afton).