Bro explained the FNAF lore

FREDDY FAZBEAR IS THE TITULAR ANTAGONIST OF THE FIVE NIGHTS AT FREDDY'S SERIES, WHO LATER APPEARS AS MULTIPLE VARIATIONS IN THE SUCCEEDING GAMES. FREDDY IS AN ANIMATRONIC BEAR AND CHILDREN'S ENTERTAINER HOUSED AT FREDDY FAZBEAR'S PIZZA, ALONGSIDE BONNIE AND CHICA. HE IS THE MASCOT OF THE ORIGINAL FREDDY FAZBEAR'S PIZZA CHAIN, AND TAKES THE ROLE AS THE LEAD SINGER OF THE BAND, STANDING IN THE CENTER OF THE STAGE. SECRETLY, FREDDY AND THE OTHER ANIMATRONICS ARE HAUNTED BY CHILDREN MURDERED BY A MAN NAMED WILLIAM AFTON. HE AND THE OTHERS ARE NOW SEEKING REVENGE AGAINST THEIR KILLER BY ATTACKING ANY ADULTS IN THE PIZZERIA AFTER-HOURS IN BLIND RAGE. HE WAS THE MASCOT WHEN THE FIRST FREDDY FAZBEAR'S PIZZA WAS OPENED IN 1983.[4] IN 1987, HE AND THE ORIGINAL ANIMATRONICS HAD FALLEN INTO SEVERE DISREPAIR, AND FREDDY WAS REPLACED BY HIS NEWER COUNTERPART FOR THE "IMPROVED" FREDDY FAZBEAR'S PIZZA, TOY FREDDY.[5] AFTER THE PIZZERIA'S CLOSING, AS WELL AS THE TOY ANIMATRONICS BEING SCRAPPED, HE AND THE ORIGINAL ANIMATRONICS WERE REFURBISHED FOR THE NEW PIZZERIA,[6] AS OF THE EVENTS OF THE FIRST GAME. HOWEVER, AFTER THE CLOSURE OF THE NEW PIZZERIA, HE AND THE ANIMATRONICS GOT DISMANTLED BY THEIR KILLER, WILLIAM AFTON. HIS SOUL, ALONG WITH THE OTHERS, WAS PRESUMABLY SET FREE, AS EVIDENCED BY THE GOOD ENDING.