I feel like that post from earlier was foreshadowing this...

(Sprintrap art by PinkyPills)

Two murderous antagonists from horror media who, prior to becoming what they are now, were pretty mad craftsmen (William Afton and Thomas Crawford, or at least the MM version of him) who discovered a special, supernatural material (Remnant and Giza Glass), which holds great importance to them and their series. As eluded to before, both became one with their creation through unlikely means which should've realistically permanently killed them (William getting crushed inside the Spring Bonnie suit and Thomas cutting himself up and stuffing himself inside of the Freedom statue), essentially giving life to their creation. They were later moved to an important location (Fazbear's Frights and the U.S. Capitol building) after being found in an a remote location (the Safe Room and the cave Freedom was found in). They both also had their daughters fused with one of their creations, which they were somewhat responsible for (Elizabeth Afton was killed and later went on to posses Circus Baby, who William Afton created, and Nina Crawford was sliced up and later put into Freedom by Freedom herself. Note that Freedom was possessed by Thomas at the time, so... Oh, that and William is technically fighting two people.). Funnily enough, both of their names include a word which are basically opposites of each other (Springtrap having the word "trap" in his name and Freedom being named... Well, freedom).