British accents have always been connected to the Afton family and almost every character with a British accent is an Afton. It’s been like this for a whole: If you have a British accent then you are an Afton. However, there is an exception to this unwritten rule. Because in SB we get introduced to a new character who has a British accent: The second therapist in the secret CDs. We have also speculated for a while Vanessa is a stand in or in some way related to Elizabeth because of their similar appearance and some details we learn through Vanessa’s therapy sessions. Well what is the subject of the first session between Vanessa and the British therapist? Vanessa’s mother. I’m not sure what this implies but I found it interesting that a franchise so particular on little character details had a British woman discussing mothers with a parallel to Elizabeth. Any further input would be appreciated.

so, to recap FuhNaffs theory states that the robot standing outside the window was Funtime Freddy and the question that Matpat brought up was y on earth would Afton be building the Funtimes so early. well i think that it all lies in ballora. Bellora is similar to robot Charly in 2 ways. 1: they both r in honor of a past relative. and 2: both seem to be possessed by said relative without being stuffed into it. with these similarities its not to out there for one to say that there creation wasn't the same miss Afton left and maybe dies which explains the grave stone outside it's her grave. and so Afton makes Bellora poring all his sadness and agony into it and soon it comes to life and Afton wants to recreate this so he starts the Funtimes, robots in Ballora's design. he tests Funtime Freddy the night he kills Charly and it kills crying child. this would be the end but in midnight motorist a merical happened, he had his alchemists fantasy with charley's death. remnant was discovered and with remnant he can build a robot son and bring his son back to life. he does bring his son back to life, then circus baby's opens, then elizabeth dies, the freddy's opens, then the springlock suits r invented, then crying child dies a second time and posseses golden freddy. thats how i feel the timeline goes. it all starts with ballora devorcing afton cuz he is a neglegent parent "the baby isn't mine" and she leaves him and she dies. afton gets super depressed and builds ballora in honor of his ded wife but she begins to act weirdly almost alive. afton wants to recreate this so he starts building the funtimes. and the prototype kills his son but the same night he finds remnent in the form of the puppet. with it he builds a robot version of his son taking the sole out of the prototype and into the robot, later that year circus baby's opens but elizabeth dies resulting in the place getting shutdown, fredbears also closes cuz of charlies death. then they open freddy fazbears pizza, henry does the pupppet carver to build balloon boy they get mangle and build the springlock suits deciding to revive the old fredbearr character in a new golden look. then in 1983 crying child dies a 2nd time when the fredbear 2.0clamps down on his head. thats it for now.

1.William being your average sexyman while in canon he's your average 70s killer fat buisness man

1. CC's name being Evan or Garret

3.Princess(Princess Quest)being Cassidy
4.Willry,in the canon,William hates henry.
5.Elizabeth being annoying

1. In videos,The aftons or whoever immediately accepting the fact they are in a video,that there is a creator who "created"them

7.Any crossover videos,like "Aftons meets MHA"or something like that.
8.Making William only mean with Michael
9.Ghosts that can transform themself into the animatronics they possess at will
10.Obsessed Ice Cream elizabeth
11.Hater Ice Cream elizabeth

1. Elizabeth being the youngest.
   
2. William simping for Henry or Mrs. Afton.
   
3. Mrs. Afton being an abusive/bad mother while William being a good father.
   
4. C.C being an innocent bean while Elizabeth is literally insane.
   
5. Elizabeth DYING to make William proud.
   
6. C.Cs name being Evan.
   
7. William or Michael being taller than the Eiffel tower. (Basically William being tall)
   
8. C.C forgiving Mike or C.C forgetting due to brain loss. (I kinda like this idea but its just common)
   
9. Glammike.
   
10. Pigtail Girl traumatizing C.C or not being a good friend to C.C. (This idea is alright but its common)
    

Nah nah they have these "aus" where Mrs.Afton is an "abusive" parent and where william is a "good" one
William also "loves"mike bc he "went" through all that shit
"AnD tHaTs WhY eLiZaBeTh WaNtS tO kIlL hIm"
Like no how can we make a character that we dont even know about a bad guy?instead of a guy we know TOO much of?
Overall these type of "aus"suck and they just use the excuse "⚠️MY AU⚠️"
i dunno if anybody will feel offended by this comment and hope not its just a little rant?ig
I only want people who have this in their au to feel offended so go on

Now some division has happened amongst some of the FNaF Fandom when it comes to solving some of these mysteries to the lore of the games, I shall throw my hat into the ring...

So firstly, let's start with analysis the Insanity Ending for starters
" It's only now that I understand the depth of the depravity of this...creature - this monster that I unwillingly helped to create. "
This is talking about how Henry somehow caused William to go on a killing spree (Maybe cuz of The bite of 83'?)
" As if what he had already done wasn't enough, he found a new way to desecrate, to humiliate, to destroy. "
This implies that that something is being ruined by William.
Possibly either Fazbear's Fright the horror attraction to humiliate the souls or something with the follow me minigames.
" As if the suffering wasn't enough, the loss of innocence, the loss of everything to so many people. "
Possibly talking about The Missing Children's Incident & how the souls are now consumed by the monstrosity of what they've become.
" Small souls trapped in prisons of my making now set to new purpose and used in ways I never thought imaginable. "
This is where it gets a bit wonky here.
Either he is talking about how they've given themselves a purpose to hunt down anyone that remotely looks similar to William or that William fused them into the Funtime Animatronics and used them to kill more kids.
" He lured them all back. Back to a familiar place. Back with familiar tricks. He brought them all together. "
Talking about Follow Me, since they were killed in the saferoom.
" Are they still aware? I hope not. It keeps me awake at night. "
I mean... do I really need to explain this part?
" I could make myself...sleep. But not yet. Not until I undo what he has done and heal this wound - a wound first inflicted on me, but then one that I let bleed out to cause all of this. "
Possibly talking about how William game-ended Charlie outside of either Fredbear's or The first Freddy's but, like any murderer, he kept nappin' them kids.
" He set some kind of trap. I don't know what it was, but he lead them there again. He overpowered them again. And he robbed them of the only thing that they had. Again. "
Maybe something to do with Shadow Freddy? He basically destroyed their vessels so technically he robbed them of their afterlives.
" I don't know how those tiny breaths of life came to inhabit those machines. "
Give Gifts. Give Life.
" But they will never find rest now. Not like this. I have to call them all back. All of them. Together in one place. "
Either he is talking about all of the Scrap Animatronics or talking about the MCI & Charlie.

Now, The Candy Cadet Stories
Some assume that it talks about William putting the MCI into the funtime animatronics, but the stories talk about a good thing trying to put fives things together because of a negative thing... plus, it talks about fives things becoming one... MoltenMCI states that the MCI are mixed into one, yeah, but later split into 3 other Animatronics, We're missing a step here.
And then one final thing that also carries this whole thing... The Fourth Closet
This is, we weren't ment to use the Silver Eyes Trilogy to solve the games, when the book came out, Scott made a post on steam saying that the books, again, are not ment to be used to solve the games, he did say that they do share a lot of familiar elements that both the books and games share, but mostly boils down to this

• William is bad guy & becomes Springtrap
  
• Charlie & Henry are good guys
  
• The Missing Children's Incident happened
  
• The Robots are possessed
  
• Elizabeth becomes Circus Baby
  

And Some other stuff but thats besides the point...
And also, The Amalgamation in the fourth closet is a separate entity that, yes, controls the Funtime Animatronics, but are not in The Funtime Animatronics like MoltenMCI states
One thing is that some look over from that post, is that he said the books are a reimagining of the games, Scott wants to tells stories, if you were a story teller, wouldn't you get just a little bit burned out on expanding the same story, you'd too want to make different stories like The Silver Eyes Trilogy or The Fazbear Frights books
Plus, we never see Golden Freddy in Follow Me, so if MoltenMCI were true, it would most likely be just the four spirit of Freddy, Bonnie, Chica & Foxy

Now, for RockstarMCI...
There isn't too much for this theory but it does have some... Intresting evidence
And this goes back one of the games a lot of you dislike mostly... FNaF AR
In one of the datamined files of the game we get something called "Faz-Facts", It's mostly the same stuff that we already have conformation about...
But one of them states that Rockstar Bonnie was Developed from the original bonnie, not based off, witch is a whole other meaning, but Developed, The Fourth Closet isn't ment to solve lore of the games, FNaF AR is...
But than again, The Rockstar Animatronics are not required to get the true ending of FNaF6, but some might say that "oh, they're just stored In a different room", look at the pizzeria in Security Breach, the labyrinth is Under The main building of the FNaF6 location...
It isn't too hard to believe that the pizzeria itself took the least damage but the labyrinth took the hit, but also, if they were stored... why would we need to buy them if we already have them?
Now, from Henry's Ending speech, it implies that the MCI kids are in the labyrinth...
So... where are they?
There is a somewhat equal amount of evidence to go with & to go against both MoltenMCI & RockstarMCI...
So, which one is it?
Now... for me, I do have a somewhat explanation for what's going on...
This is just my opinion though, so don't downvote me into UCN with Cassidy...
But I think... They do not possess anything
NOW HOLD ON, HEAR ME OUT
Think about it, in UCN when the mediocre melodies say their spooky lines
Oroville elephant will say, with Cassidy in the background,
" He tried to release you. He tried to release US. But I'm not gonna let that happen. I will hold you here. I will KEEP you here. No matter how many times they burn us. "
No matter how many times they burn us...?
They would imply that Cassidy is attached to William, I mean, no wonder good ol' bill is still alive.
Even in the logbook, both Cassidy & The Crying Child are together, they seem to be tangled together in someway, and the logbook belonged to Michael Afton as well, so...
Maybe, Cassidy & The Crying Child is attached to William & Michael somewhat? It's kinda unclear...
But, if that can logic cam apply to Cassidy & The Cryint Child, who says it can't apply to the other spirits!
Also, after Follow Me, the spirits are freed from their animatronic vessels, but they didn't really have a choice since the Robots are in a VERY damaged state.
And, where do they go? Happiest day possibly happens after FNaF6 cuz the MCI kids are in the labyrinth somewhere & the robots they were bound too are broken, so what happens to them? They kinda just... wander... going to pizzeria to pizzeria.
I know, it's unsatisfactory to lots of you, but not everything is satisfying, just how in some games, the good ending isn't the best ending...
Also, it let's us see the Funtimes as new characters (since some of you seem to dislike new characters now-a-days), cuz where are the implications that the MCI kids are on the sister location?
Anyways, that's all I really can say, I'm not really much a theorist so don't come banging down my door, I kinda just wanted to put my opinion out there, but if you want to believe one of those theories, go right ahead, don't let this post stop you from it cuz MoltenMCI is a decent way to look a things (despite it's flaws).
As always, see y'all on the flip side!

so, I believe that Og Freddy Fazbear is a old Fredbear animatronic renamed originating from Freddy Fazbear and i have evidence. So the thing that initially through me off with the springlocked animatronics coming from Fredbears family diner is the old phone guy tapes which say, "uh hello and welcome to ur new carrier as a performeentertainer for Freddy Fazbears pizza, right now we have 2 specially designed suits that double in both animatronic and suit." the game welcomes u to Freddy Fazbears pizza not Fredbears family diner which screamed as very important detail. so i tried to find a place that shows Fredbears family diner with out the spring bois and i found it. In the save him minigame we play as Freddy Fazbear not Fredbear. now incase u don't remember in the minigame save him u play as Freddy holding a cupcake ur task is to give the cake to children. this is where Charly dies. i searched and that sprite isn't an offical Fredbear sprite. so it has to be Freddy. but thats just a minigame circus baby wasn't really outside and the animatronic probadly didn't have 3 toes when standing outside the room what can we use to prove this. well after searching i found the anwser. look at the fredbears family diner photos. we see one of Fredbear and one of Spring bonnie right wrong. take a look at the old Fredbear poster again. the bear appears to be a bit closer to brown then yellow for that artstyle and look at the hat and bowtie all iderations of fredbear after fnaf 4 have had a purple hat and bowtie EVERY ONE and yet the fredbear poster has black hat a bowtie just like freddy fazbear. so there u go freddy fazbear used to be called fredbear and probadly had a cupcake instead of a microphone but what does that mean for the large whole. well it puts fredbears family diner as the first location that closes leading to the creation of fazbear entertainment more on that in a bit cuz it is other animatrionics that makes this impressive for this places the spring suits in freddy fazbears pizza just like the phone guy says it is. but what about springbonnie, well without a second animatronic other than the puppet when could serve as spring bonnie well none other than our favorite 5 fingered fellow glitchtrap. thats right this puts the old glitch trap suit originating from fredbears family diner. it serves as a reasonible explination. now one question is when would this supposedly be happening. well for that we need to turn to fnaf 1. in the fnaf one paycheck we have the date 11-12-xx and on saterday 11-13-xx and when we look at calenders from the 90's cuz the 90's had minimumwage of 4 dollars an hour we find the only year to have this date to be 1993. so fnaf 1 takes place during 1993, and phone guy says, "if i was forced to sing those same stupid songs for 20 years and i never got a bath then i would probadly be pretty irritable at night too." subtract 20 from 93 and we get 73 meaning that these guys have been around sense 1973. so fredbears family diner existed during 1973. now one final question that u guys might be having is that y would afton kill charly in 1973. the anwser his wife left him as simple as that. at this point the wife is gone. the lady that we see sitting in the chair watching the tv in midnight motorist that aint miss afton thats elizabeth, miss afton is long gone and probadly ded.

Anxiety Babble
Just want to get this out of the way now. I have not been able to get my hands on the books myself and my knowledge of this series is strictly secondhand via watching theory videos, let's plays and minor playtime from myself.
I am still getting into and coming to know the lore, lore that no one has truly cracked 100% yet. So please be kind when responding to my silly thoughts.
​
The Theory
Gregory is human and the real robot child is Cassie, the girl we will play as in Ruin.
Also they were 'raised together'.
The Mimic is several entities.
​
Gregory Is A Real Boy
There is a bit of debate over this issue as I recently saw a post on here showing as much.
Originally I too believed MattPatt's theory on how Gregory is a robot, built to replace William Afton's son, the crying child. However I saw some pretty good arguments making me think otherwise.

1. The Ultimate Guide stated him to be human
2. Gregory is said to have had parents and a good childhood
3. He wouldn't be the first to get brain washed

Basically my thoughts are that a replacement for the crying child was needed. He is patient 46 and quite possibly another victim of the brain washing from VR.
VR was released as a game meant to both distract everyone from the truth but also to help William Afton/Glitchtrap brainwash others into helping him get into the material world.
Vanessa was only a partial success. This is partly due to her being easier to manipulate than others, but who would be even easier to manipulate? A child.
We already know Gregory loves games and places fairly high in all of them as indicated by the initials GGY on all of the arcade games.
What if Gregory played fnaf vr and was lured by Glitchtrap and brainwashed? He is then taken or mind controlled into running away. The birthday set up is to help brainwash him.
He wasn't alone in that room though. The notes all over that room were him communicating with the real robot child.
​
Entering The Scene - Cassie
If you have the time I suggest you go to YouTube and look up Funaff as it is his theory/explanation that really has me thinking about this.
John explained/theorized several things

1. Edwin from the book is a parallel for Henry
2. David is Charlie's parallel
3. The original mimic is Baby/Robot Charlie
4. There were other Charlie bots

I don't want to put words in his mouth but I think he implies that Cassie, the girl we are speculated to play as in Ruin, is a young Charliebot.
Another parallel that he pointed out was the location Gregory was kept in is at least structured in the same way that Henry/Edwin's workshop is described in the books.
My line of thinking here is what if that is Henry's workshop in Security Breach? Its possible that a child version of Charliebot was left behind.
The original plan may have been to use her as a replacement for Elizabeth, but she wasn't as easy to manipulate. This leads to the new plan where Vannessa is the replacement.
Gregory still needed a friend to keep him occupied though so the Charliebot, Cassie was booted up.
Those colorful sticky notes are from Cassie and Gregory communicating. The one who is learning to write and talk like normal is Cassie.
There Are Several Mimics
The original mimic would be the young Charliebot. She was made to replace his daughter whom Afton had killed.
Older Charliebot, the one that would later become Circus Baby, was the second mimic. At least she was meant to be.
The older Charliebot was incomplete, but she had Henry's mimic program installed, she was meant to be an older Charlie after all.
After being turned into Baby she was corrupted. She was made to kill.
Something I am curious about is if the girl asking about Baby being made for her is actually Elizabeth? Is it possible that the girl was actually Cassie, the child Charliebot?
Would the mimic be able to tell the difference? Especially after being possessed by Elizabeth?
Anyways, John/MattPatt (can't remember who said it) had a good point towards Baby being the mimic, not only can you see the parallels in the books, but in Sister Location Baby talks about pretending – aka mimicking.
If this program was already in the hands of Afton I think John was right about it being used in the system for Security Breach, making the other animatronics pretty much mimics of Charliebot/Baby.
The building would essentially have been exposed to Charliebot / Baby Ai and that is the voice we hear in Ruin not Gregory who escaped.
​
Some More Details/Thoughts
Gregory being able to understand the symbols about dodging and shooting could be from talking to Cassie. She made it up after all – well Charlie did.
Cassie being raised with him makes a bit more sense as how would he know who she is otherwise?
Another thought I had was about where she is during Security Breach? What if she had been helping Gregory to break out, but Vanessa was on to them?
Cassie escaped but Gregory had got locked in. Ultimately he does escape but Cassie doesn't know as she was trying to break back in to help him. That's why she is so eager and willing to help "Gregory" in Ruin.
The mimic senses Cassie and is probably desperately looking for a way to escape or for revenge.
​
The End
​
I dunno this probably doesn't work how I think it does. Would love to hear thoughts on it all though. Any points you want to add or to challenge are welcome. Y'all more than likely know way more on the topic than me, but I'm slowly getting the hang of this... I think 😅

On one hand, she's just a young child who's a victim of William's abuse
On the other hand, she acts like an adult despite being so young which means she is perfectly aware if she's doing something bad
Is she really pure evil?

After figuring out what theories I believe, I decided to make a Timeline of all my ideas. This is Part 1 covering Fredbear's to the MCI. This timeline also incorporates StitchlineGames and the Tales stories. Until all the books release, I will assume that all the Tales stories are in continuity. I'm gonna start with the creation of Fredbear's Family Diner as everything before is essentially headcanon aside from the existence of a Fredbear's Singin' Show but that isn't super relevant. Feel free to ask questions in the comments. The next part I'll try to cover everything from the aftermath of the MCI to FNAF 4's nightmares.
Henry Emily and William Afton come together to create Fredbear's Family Diner containing two springlock animatronics, Fredbear and Spring Bonnie. There will later be a Security Puppet added to the location to look after Henry's daughter, Charlie. This is the location the Security Breach posters are from.
William has a family at this point which is shown in the Staff Bot Family. The members consist of William Afton, Clara Afton (placeholder name), Michael Afton, Garrett Afton (placeholder name), and Elizabeth Afton. William had quit his job to work on Fredbear's with Henry which Clara doesn't approve of as she worries that it won't be successful and that they won't have enough money to support their kids. Clara and William eventually divorce and somehow William gets custody. William is not the best father and is abusive towards his kids as seen in the trilogy novels with how he treats Elizabeth and as will be seen when we go through this Timeline. All this is implied by the Afton Family Staff Bot unused lines and Vanessa's past in the Security Breach CDs that seem to be parallels to the Afton Family.
It's implied by Vanessa's past that after William got custody of the kids, Clara killed herself.
William starts having a drinking problem over the death of his wife, the only person he actually cared about as he's shown as neglectful towards his kids and sometimes even abusive. William is kicked out of Jr's and, still drunk, drives to Fredbear's where he sees Henry's daughter had been locked outside by some bullies. William, not entirely thinking straight and envious of Henry's perfect family, decides to take his anger out on Charlie, killing her. After realizing what he's done, he drives away. However, the Security Puppet had made it's way outside, becoming drenched in the rain and breaks down right after reaching Charlie. Charlie's soul possesses the animatronic.
The wickedness of William manifests into Shadow Freddy, a shadowy version of the mascot of Fredbear's, the location Charlie died at. Shadow Freddy lures Garrett to Fredbear's where he mistakes Shaodw Feeddy as Fredbear. Once at Fredbear's, he sees Charlie's body and assumes Fredbear had killed Charlie, leading to his fear of the animatronics. Meanwhile, William arrives back home to find that his son had run away and promises that he'll be sorry once they return
Inspite of the tragedy, Fazbear Entertainment opens Freddy Fazbear's Pizza which quickly grows in popularity with a cartoon, plushies, masks, and figurines releasing of the characters that year. Fredbear also gets a redesign replacing the black hat and bowtie with a purple hat and bowtie, as well as making him more yellow. Spring Bonnie also gets a redesign, thos time having a buck teeth and little bunny tail out the back. The original versions of Fredbear and Spring Bonnie are used at Freddy Fazbear's Pizza.
As buisness is booming, William started to notice some weird things happening with the Security Puppet that has been decommissioned, it's starting weirdly when he's present, like it's aware, it also seems to be able to go anywhere Inspite of it's programming. This only started happened AFTER Charlie died, something was definitely up. He theorizes that it The Puppet may be possessed in some way by Charlie. If this is true, William could uncover the secret of immortality. So, William gets to work on figuring out how exactly it all works. He theorizes that it may have something to do with the emotions that Charlie felt when she was killed, fear and agony. But, he needed a test subject, someone with a lot of fear towards the animatronics. Luckily for him, his son had just began to fear Fredbear, he didn't know why, but he could use this to his advantage.
He moved his family to a house closer to Fredbear's and kept the old house in the woods as a test house. He placed animatronics with illusion disks that would make the viewer see nightmarish versions of these characters. William placed cameras around the house and started his plan. Every night he would take Garrett from their house near Fredbear's and place him in the previous house. He would then wake Garrett up and let the experiments begin. William didn't care that he was torturing his son, it was all in the name of making himself immortal, which is all he cared about. This torture would continue night after night until Garrett was convinced the animatronics would catch him and eat him. It didn't help that he accidentally saw someone being suited up in the mascot costumes and thought it was the spring characters eating people. These nightmares are shown to have actually happened at some point in the Timeline by Sister Location.
Because William was stuck in his own experiments, Michael had to look after Garrett and Elizabeth. Michael had it rough, his father neglected him and his mother was dead, and it didn't help that he had to essentially babysit his crybaby brother that wouldn't shut up about animatronics trying to eat him. At least he didn't have to deal with Elizabeth too much, she was off at daycare most of the time anyways, but Garrett was too old for that. Mike started taking his anger out on his brother, scaring him with the Foxy mask. He found joy in his brother's tears of fear and continued to do this.
William saw what Mike was doing, but instead if stopping it, he allowed it, this would help increase his son's fear, making experimentation that much easier, and he was already seeing results from his tests on emotions. He decided to turn his son's bullying into an experiment. He placed cameras in the Fredbear Plush that Garrett had and a speaker, using it to watch and talk to Garrett. He pretended to be a friend but was really just trying to scare Garrett by doing things like reminding him of what he saw and telling him his brother was waiting to scare him but not where. Sister Location and some of the Frights stories heavily implies William is the Fredbear Plush in the first 4 minigames
As Garrett's birthday came closer and closer, William forced him to have his birthday at Fredbear's despite his objections to it. As the day came closer and closer, the bullying got worse and worse until the day of the party. Michael had brought his friends and wanted to have some fun with his brother. After some mild teasing, him and his friends took Garrett up to Fredbear to give him a big kiss. However, his head got stuck in Fredbear's mouth, and as Garrett wiggled around to get out, the group just laughed and laughed and laughed until the animatronic malfunctioned, crushing his head. The boys stopped laughing and stared in horror. They quickly tried to think of excuses, "He tripped and fell on Fredbear's teeth. Not our fault." But it was their fault.
Garrett was taken to the hospital and was dying. Michael apologized to his brother who could hear all of it but then he heard the voice of his plushie but it sounded different, yet familiar. It was Charlie, she had came to help Garrett, promising to put him back together, but she doesn't know how, but she'll find a way. After Garrett flatlined, his soul possessed the only metal near him, the Fredbear Plush. William moved the Fredbear Plush to the underground facility where it would stay for a while, not knowing it carried the soul of his son.
Edwin Murray had been working for Fazbear Entertainment since September of 1982 and was helping create the animatronics for other restaurants while also looking after his son, David. He decides to create a robot to look after David for him and spends the next 22 days creating the Mimic. The Mimic starts to mimic David, pretending he was holding the same Tiger plushie David had, being able to play patty cake, learn David's made up sign language, play catch, etc. Soon Mimic started doing more than just mimicking, it started responding and Edwin feels confident enough to leave David in Mimic's care.
A few days later, David goes to play outside, waiting for his dad but Edwin thanks Mimic will take care of him while he wakes up. However, when he gets outside, he sees David chasing the ball into the street where he is hit by a white van, killing him. For the next 2 weeks, Edwin mourns David's death before getting so mad at Mimic for mimicking David that he destroys it, infusing his agony with Mimic, an action which would have unforeseen consequences.
January of 1985, Dominic, Harry, and Glen are sent to Edwin's factory to clean up the mess Edwin left and make repairs after Edwin had vanished. They learn of a team that was sent in December to do the same thing, with that team finding the Mimic endo and repairing it, giving it legs. The trio find the bodies of the previous team mangled in the fridge with one of them hanging with his entrails spilling out. The trio are then picked off by the Mimic in different costumes, first is Harry who gets his brain pulled out, then there's Glen who gets his head slammed into the brick wall, finally there's Dominic who gets his trachea pulled out.
It's now summer of 1985, the Springlock Suits have been discontinued thanks to a failure that happened at one of the sister locations. Fredbear and Spring Bonnie are kept in the building but are told not to be worn. William disregards this, wanting to try another experiment. He thinks that if he were to kill someone and stuff them into an Endoskeleton that it would cause that person to possess the suit. So, William does exactly that. His first victim is Susie who recently had a dog get runover by a car, she's not exactly having the best day. So, William thinks she's an easy target. He dresses up in the Spring Bonnie suit and goes to Susie, telling her that her dog is still alive and that all she has to do is follow him to where he is. Susie follows Spring Bonnie, happy to see her dog only to be killed by William who stuffs her body into Chica.
Next victim is Jeremy whose parents left him alone at Freddy's. He tells him that he can help find his parents, luring him into the Safe Room and stuffing him into Bonnie.
Next victim is Gabriel who is having his 7th birthday party. He's struggling with homework, so William decides to help him, leading him into the Safe Room where he's stuffed into Freddy.
Next is Fritz who he tells about his friends that are all having a party in the Safe Room without him and that it'd be a shame if he was left out. He lures Fritz to the back and stuffs him in Foxy.
At this point, people are starting to catch on that kids are going missing. "Where's Susie?" "Where's Gabriel?" "Where's Fritz?" In the chaos, William takes another victim, Cassidy, she practically ran right into him. She was stuffed into Fredbear.
Finally, there was Andrew, William was specifically brutal with this one. Throwing a bag over his head, knocking him out, and dragging him into the Safe Room where he's stuffed into the only other suit, Spring Bonnie.
Without a suit, William is spotted leaving the Safe Room on camera and becomes a key suspect in a the case of 5 missing kids. Andrew was never reported missing, likely he had no family to report him missing, just some kid in the wrong place at the wrong time. The police knew it was William, there was no way it wasn't, but they couldn't find the bodies and William seemingly had no motive. Why would the owner of Freddy's do something like this at risk of losing their company? The risk didn't make sense. William also seemed very helpful during the investigation, getting another employee arrested, one that was convicted. Either this man was guilty or someone did one hell of a frame up.
This entire event was witnessed by one of the many Mimic robots which caused the program to start Mimicking what happened in the MCI, leading to the shutdown of the project.
All this info on the MCI is shown throughout the games and books but mainly the specifics are only really shown in Fruity Maze, Toy Chica Highschool Years, Pizza Party, and Into The Pit with the order largely coming from the Mangle's Quest code and Security Breach balloons.

I'm new to this meddit community, so I don't know if there was the same question earlier.
As far as I know, he doesn't really like his eldest son. But on the Wiki about the game, I found information that Afton also disliked the Crying Child. I have not found any confirmation that he does not love his daughter, cuz William even wanted to warn Elizabeth against Baby. So it was only Michael he didn't love?
And another question. So why did he hate Michael? Because he killed his brother or for another reason? In FNaF 3, as I understand it, the protagonist is Michael. The only real animatronic there is Springtrap, which is Michael's father. Why does he want to kill his eldest son?
I'm so confused about lore! But this question torments me the most at the moment.