When i say back-stage, i mean, a story that isn't actually present in the game, like a story that surged from game parts. I'll start: FNAF Yep, the FANDOM is a COMPLETE SHITSHOW but if you look at the story videos, you'll see that the story is out of theories taken from some things of the game, actually, that story is very hard to explain and research(seen videos that last +2 hours)
Undertale. You get an addicting game, then come the theories. They are plenty of it, and some of them are pretty insane.