Sometimes ponies get lost in the streams of time, never returning. Sometimes the consequences of their actions are infinitely small. Sometimes however, the whole world changes as a consequence of their actions.
Equestria had dark ages, but none had been as dark as these. It had always been some force of evil trying to bring Equestria down, always somepony to blame, always a clear definition of an enemy. What had caused our downfall after all? There is no clear answer here, just a lot of arguing.
It may have been Twilight herself, it may have been the paradox of time, it may have been the hatred.
Twilight's studiousness caused her to invent the potion in the first place. Of course she only wanted to help us, to create something that would forever unite us and not divide us. The paradox of time forced Twilight to do what she has done already. However, the hatred of Nightfall's Radiance was what destroyed her friends and caused Twilight to transform.
Looking at it from the distance, we can finally see the interconnections we couldn't see before. All had been inevitable, impossible to happen in any other way. Every single detail was mapped out from the start.
It creates a certain feeling of sadness, seeing how she had been chained to the rules. Loosing the free will is something I can hardly even imagine.
This was her story and I hope you have learned well. I will continue raising the sun and Luna will continue raising the moon. Life is going to continue as if it had never happened. Maybe not from today on, maybe it will take hundreds of years, but at some day it will be forgotten. This is the reason why I write it down here in these very words. May the lesson be learned and never repeated.
Celestia looked up. She had written so long, it made her sad seeing that she had finished. Could she just let go of it? She hovered the pages over to her desk, where pieces of yarn were already waiting to be bound with the pages. She remembered. All those memories, all those thousands of years, a whole eternity of lessons to be learnt. Another book in her library, another chapter of her life and yet there was no end, no success, no goal. The yarns flew through the beautifully ornamented holes in the royal paper. Could this all just be another chapter? Could she really put it all back into her shelf? She had loved her. She had loved Twilight as her child and she could still not believe that she had become Nightfall's Radiance. She could still not believe that Twilight would be gone for the rest of her life, she would be gone forever. Could she really put it all back into the shelf? Could she just end the chapter, which has been her love and her life, maybe the closest to a daughter she would ever have? Trying to put that story into her library was killing a part of herself. It would be impossible to ever forget.
Luna slowly trotted by her side. She didn't say anything, word had lost their necessity so long ago. Luna slowly hovered the book into the air, slowly turning the pages until she reached the end. There was a deep sadness inside of her voice, a sadness that reminded Celestia of her own:
"It is a nice story isn't it? A story speaking to you and yet you will continue living on while the story will have ended. Maybe you will continue your life like nothing had happened. Maybe you will start to think what can happen if you try evade the inevitable. Maybe you will see that we all have our secrets and we are not all the same, no matter how similar we seem. Maybe you will see that we are not so different, no matter how alone we feel. There are thousands of stories with thousands of lessons and thousands of unfortunate writers.
Every story has a writer after all. Somepony has written this story only for you to read these very words. And even after they are dead, their story may continue to be told. It is a nice thought, isn't it, sister of mine?"
"I just wished it had been just a bit longer, a bit more of happiness and a bit less tragedy to be told. Every second longer with her would have been worth the thousands of years to come."
A single tear dripped of her chin, falling to the wooden ground of the library. She had mourned for days and yet she couldn't find her piece even after writing a story that would live on forever, just like her.
"Let us lower the sun together today, shall we?"