It's easy to get caught up in the jumpscares of Five Nights at Freddy's and leave it at that. But underneath those scares, there's a very disturbing story hiding in the background of the series—and players are still hard at work at trying to figure out all the details.
Concretely, what players know is that there have been multiple incidents, all involving murder at Freddy Fazbear's pizza establishments, which lead to these restaurants being shut down. The thing that people can't decide on is who the murderer(s) actually are. Some people think it's the player. Some people think it's someone outside of the game entirely. Here's a new theory by The Game Theorists which puts forth a more unsettling possibility: it's the guy nobody would suspect. The guy that talks to you on the phone. It seems unlikely, especially given how nice the guy sounds, but The Game Theorists do a pretty good job of breaking down why they think it's phone guy.
First they put forth a timeline for all the different restaurants, from the ones we see in the games, to the diner that started the chain in the first place. The Game Theorists argue that the mini games found in Five Nights 2 actually show that first diner at one point—you see a single Freddy animatronic trying to take cake to a bunch of kids in a small establishment. The first restaurant that sparked it all was probably smaller than both the pizzerias found in 1 and 2, and it's not unreasonable to think they'd start with a single animatronic, too—the most iconic one.
Assuming that's true, let's look at what happens in that mini game. As you give cake out to all the kids, you see another crying child that's separated from all the rest. Eventually a man in a car comes over and murders the kid. The Game Theorists make a good case for why the kid that dies in that mini game goes on to be the puppet animatronic that comes after you if you don't keep the music box winded up in the main game. It's probably no coincidence that that same puppet attacks you after you play the mini game with the cakeless kid, too.
Presumably it was this incident that prompted the owners of the original diner to sell to the company that ends up making Freddy Fazbear's Pizza. It's at this new restaurant where a murderer ends up taking out five children—the bodies are never found, though it's widely assumed these kids end up being stuffed inside the animatronics—hence the bad smell that the phone guy mentions to the player.
This theory suggests that the souls of the children are tied to the animatronics by the puppet, since that's what one of the death mini games in 2 suggests. More interestingly, the mini games suggest that the guy that kills the group of children also killed the first kid in the diner. This explains why the animatronics would go on to have a safety measure that can identify sex offenders.
All of this lays the foundation for the big reveal here: that the guy that always talks to you on the phone right before your shifts is actually the person behind all the murders. There's good reason to be suspicious of this man, no? For one, he seems to have a long history with the restaurants, including the first one. He doesn't seem to like the puppet animatronic, though he does mention liking the Foxy animatronic. One of the mini games shows the murderer watching Foxy with a smile. And more importantly, one of the mini games shows what appears to be a guard with a phone—and if he touches you, you can't save the kids. That seems like too big of a coincidence.
You may be thinking to yourself, wait a minute, wasn't the killer caught? That's what one of the games tells you outright. But, hey, it's still possible that person was framed. With the phone guy being so eager to put you in the day shift, it's not a stretch to think he would want to frame you too—just like the first day shift guy, who supposedly tampered with the animatronics. But who knows! This is a fan theory, one of many. It's pretty convincing, though—you should definitely watch the video to see what I mean, because while I've summarized their arguments in this text, there are a bunch of details in the actual video that are necessary to understand the full argument here.
What do you think?
Game Theory: FNAF 2, Gaming's Scariest Story SOLVED! [The Game Theorists]