A possible concise summary is:
This is a video by Game Theory that attempts to explain the entire lore and timeline of the Five Nights at Freddy's series, based on the games and the novels. The video covers events from the bite of '83 to the ultimate custom night, and reveals how William Afton, the main villain, experimented with remnant, a substance that contains the souls of dead children, to create and possess animatronics. The video also explains how Michael Afton, William's son, survived being scooped by Ennard, a fusion of animatronics, because he was actually a robot rebuilt by his father after dying in the bite of '83. The video ends with Henry, William's former partner and the father of the Puppet, burning down the pizzeria simulator and freeing all the trapped souls, except for Golden Freddy, who drags William to hell. The video praises Scott Cawthon, the creator of FNAF, for his storytelling and invites viewers to buy his merch that contains a mystery to solve.
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