fnaf is a game and what first meets the eye that 1: there as robot aka animatronics. 2: kinda creepy. 3: they attack u. But lore is dark. The animatronic have DEAD kids within them which were killed by willaim afton who co-founded fazbear entertainment and the reason to kill was for 1: to save his youngest/ young boy crying child and 2: soul remnant

(theres a butt-ton of lore/ story) he (probably) got killed by the one he shouldn't have killed aka golden freddy aka cassidy who basically was a vengeful spirt 1 thing leads to another aka he got kill him kill willaim by a spring-lock failure basically willaim hid in a special suit which was not only a suit but doubled as a animatronic when switch to suit to robot mode so yea there was rain so it basically mades the springlocks loose which then turns into robot mode (idk im not a fnaf nerd lol)