"ITS A FUNNY THING ISNT IT? THE MORE YOU HURT SOMEONE, THE EASIER IT IS TO MAKE THEM STOP LIVING. BUT NO MATTER HOW MUCH YOU Love SOMEONE, YOU CANT BRING THEM BACK FROM BEING DEAD."
– Notch talking to Steve
Disbelief Notch is an AU where Notch is the final boss instead of Herobrine Herobrine stops Notch from fighting the protagonist in snowdin trying to do it himself but dies. Notch has lost faith that you can be good and fights you.
What happens if Herobrine dies before encountering him on the Judgement Hall? You will have to fight Notch on a Genoicde/No Mercy run, causing Notch to be the brother that fights you in the corridor.