Frostfern10
What if the happy ending you see is a facade?
Frisk learned the truth many timelines ago. That the world they supposedly experienced and remembered did not exist. That there was no such thing as the monsters being free on the Surface, for it had only brought them back to their last save point.
Out of desperation, they reset the world numerous times. By the time guilt stopped them, the resets forced the world into a terrible situation, where a deep corruption lurks, sending the Underground into chaos.
With a great darkness shrouding the Undergound and the remaining specks of hope flickering out, it may be only a matter of time before the world fades into the abyss forever.
(Currently on hold)