All this time, Luna. All this time, I thought you were happy. All this time, I believed your lies when you said you were fine. You hardly ever complained about our rule as the sisters two, nor had you ever revealed your woes to any other.
You were my sister, dear Luna. Why didn’t you tell me before?
Why was it that you opted to hide the dark secret of Nightmare Moon until it was too late? Had I ever wronged you? I do not understand, sister.
Don’t you remember who lovingly watched over you in our early years? The sister who agonized over your well-being during the wartime years, the sister who had shielded you at times from those who believed we were inferior, the sister who you knew as Celestia.
Please, dear sister. Tell me. Why?
Was it because I hid you from praise to prevent you from becoming too prideful for your own good?
Was it because ponies slumbered during your night and danced during my day?
I believe I may not ever be able to understand true loneliness, sister. Or perhaps, at least, not until that day. I have come to the habit of convincing myself, every morning and every night, that one day, you will return. Not as the vengeful Nightmare Moon, but as my sister and everlasting friend.
It is hard to believe that nearly a thousand years have passed since I turned to performing what I previously thought I’d never do. Yes, sister. I remember the day when I banished you to the moon from nearly pure rage. It was a curse of anger, of confusion over why one would betray their own family.
A thousand years. A millennium has passed since I have last gazed at my living sister in the flesh. A thousand years to debate over my own decisions. A thousand years since I have last felt true joy.
It is true that over the centuries I have taken on many fillies and colts as my personal protégés, sometimes to truly refine their abilities for the good of Equestria, and sometimes in attempt to fill the hole in my soul that you left behind when I banished you so long ago.
It’s sometimes hard to gaze upon the moon at night; to stare into the silhouette emblazoned onto its face, an unforeseen consequence of your banishment, I’d presume. Though it’s long since become a common occurrence, with some ponies referring to the specter as “The Mare of the Moon”, I still know it as a sign of you. A sign of my younger sister. The mark of Luna.
Sometimes, I find it difficult to perform day-to-day duties without thinking back upon you, sister. In the past, throughout my many protégés, I’ve more often than not found myself gazing upon the young fillies and colts, entranced by their playfulness and innocence. They, unlike myself, could easily live a lifetime carefree, unknowing the darker side of emotions that to this day, still boil within me. They remind me of you, Luna. They remind me of our early years, when we too once roamed the land without a care in the world. They reminded me of us.
The curse shall lift in only a matter of time. There isn’t much time left before you are once again free to return. Please, sister. Forget your ambitions of eternal night that Nightmare Moon has placed upon your mind. Fight off the dark plague that has invaded your body, and let us be sisters once more. I have no will to fight you any longer, and on the day of your return, you may find me in the highest tower of Canterlot Castle, gazing upon the moon. I cannot let myself harm you again. I don’t think my heart may be able to handle being broken another time. Whatever you may bring upon your return, please do not bring about eternal night, sister. You do not know the effects of even prolonged night upon the crops. Ponies would die by the millions of starvation without the warmth of the day to grow their crops by. I know you must feel vengeful for what you consider as my sins against you, but please, sister. I just wish for your return.
In other words, welcome home, Luna.