Alright, since no one probably understood ANYTHING in this mish-mash of random nonsense, so I am going to try to give some insight on what's going on in this fic.

Plot: In this particular alternate universe of Equestria, fanfics written about the show aren't just fanon. They are spiritual entities that inherit the spirits of the people who write them. One day, the spiritual aura of the fics grows so strong, that they wish to coexist with the very fictional universe that they are supposed to represent, Equestria. Thanks to Pinkie Pie destroying (or toppling) the fourth wall, this task is made simple, and fanon is infused with canon, creating a multiverse of alternate realities. Being the ruler of Equestria, Celestia surveys these alternate realites and is so horrified upon the sight of her figure in fanon which is now canon, that it eventually leads her to have a conflict with her now-canon inner dark self inside her mind. So...yeah.

This story is unbelievably stupid, but it is not seriously written, and the reason the plot in this fanfic is so shoddily explained is to add to the utter nonsense of it. I hope that kinda helped to better your understanding.