If there was one good thing Luna had found about retirement (she really hadn't wanted to step down so soon, even to make way for Twilight. But Celestia had convinced Luna it was for the best), it was that she was now free to pursue interests she had previously not had time to invest in. Sure, she still had her responsibilities tending to ponies (and other creatures) dreams in the dream realm, but that still left her with time to kick back and relax with a good book or two.
Heck, the former princess felt sorely tempted to contact Twilight and see about arranging an Equestrian book club. Maybe she could even see about getting that new library for Ponyville to replace the Golden Oak Library, a task that Mayor Mare had promised would be on the "To do" list, but had never gotten around to actually doing.
So it was that the younger royal sister was spending another glorious day on the shores of Silver Shoals doing what she liked doing more than anything: Relaxing in a beach chair with a stack of books chosen at random and placed beside her in no particular order. At least unlike her first time sunbathing, the alicorn had remembered to wear lots of sun block (as her sister had told her afterward, sunburn wasn't the only thing one could potentially contract if they didn't protect themselves from the sun's rays). The sun was shining bright but not too bright, so Luna didn't feel the need to wear her sunglasses.
Using her magic, Luna floated up the first book from the pile and prepared to read it. She enjoyed all kinds of stories, even the occasional adventure or romance novel despite her preference for low intensity, simple stories.
Immediately, the book caught the former princess' eye. The spine was a dark, dull blue in color, and the cover depicted a very familiar looking unicorn stallion on the left, while on the right was depicted what could best be described as a pony made entirely of shadows given its inky black appearance and curved horn. Examining the title, something clicked in Luna's mind as she read it to herself: Me and My Shadow.
"Could it be?!" Luna thought to herself as she opened the book and searched diligently for information about the author. Upon discovering the name "Stygian" printed there, it came clear to the alicorn. She remembered now where she had heard that name before: The scholar who had introduced Starswirl to the group of ponies that became famously known as the pillars, the ones who planted the seed which in turn had become the tree (now treehouse) of harmony.
Going through the book afterward, Luna found herself unable to stop reading passage after passage as Stygian laid bare his descent into darkness, of giving himself willingly to a force that promised him the power to get even, of forcing the ponies who'd once called him friend to sacrifice themselves just to stop him from conquering Equestria. Needless to say, it reminded her very much of her own troubled past, of how she had once put her sister in a similar situation.
The former princess of the night had already suspected she and Stygian shared much in common just from what she had glanced at in his dreams, and the time she had recruited him for a top secret mission that she had still not told her sister about. But never she had imagined the wounds ran so deep, that the regret was still there even if it was heavily buried.
Well, there was only one thing to do. Luna immediately closed the book, and without thought for the dozen or so other books that were piled up beside her, she lit up her horn and disappeared. Reading could wait, there was a conversation she needed to have with a certain scholar.
Stygian was doing what he'd been doing every day since getting back from limbo and being freed from the influence of the darkness: Updating his records and knowledge of Equestria. A lot had changed in the time he'd been away, every day seemed to bring something new, something that was begging to be observed and written about so that future generations would know about it. And to think, the ponies in his village had once scoffed at his intention of becoming a scholar.
The somewhat scrawny stallion was, needless to say, quite surprised to be greeted most unexpectedly by none other than Princess Luna (or ex-Princess Luna to be precise). He jumped back a bit and immediately bowed his head in respect to his visitor! "P-Princess Luna! A thousand apologies! I was not expecting you, please forgive the state of my humble abode."
Luna did her best to suppress a smirk as she motioned a hoof to the scholar. "At ease, Stygian. There's no need for such formalities. After all, you should surely know by now that I am no longer royalty. I am but a commoner not unlike yourself," In a somewhat humorous tone of voice she added. "Besides, a bit of messiness is to be expected given your line of work. Even Starswirl the Bearded himself could be very disorganized and messy, you should've seen the state he left his study in when he went off to join the pillars. It's a miracle he ever found anything amidst that clutter."
Stygian still swallowed hard. "Even so, you deserve respect. You and your sister were our nation's sovereign rulers until just recently. Even now, ponies still look to you for advice and guidance."
The former princess of the night nodded ever so slowly. "Maybe so. After all, I still patrol the dream realm as needed. That is my burden to bear, and I do not foresee that changing anytime soon," Then she cleared her throat as she motioned for Stygian to rise. "But I am not here on any sort of dream related business."
"Then, why come to see me on such short notice?" Stygian pondered in a puzzled tone of voice (and matching expression).
Luna chuckled a little. "I suppose I just have a flare for the dramatics. Old habits die hard, as they say."
"Yes, I suppose they do," The scholar admitted with a blush. "Lots of ponies say I'm old fashioned because I still wear my cloak. But I've worn it for so long it's become a part of me, I couldn't imagine being without it now."
"Indeed, that cloak is very much a part of your identity. But it is not the only thing that is heavily associated with you. And that is the reason for my visit today." Luna explained.
Still puzzled, Stygian asked. "Whatever do you mean, pr... er ex-Princess Luna?"
The alicorn with a coat the same dark blue as a night sky decided not to answer with words. Instead, lighting up her horn, she presented a book whose title needed no introduction to Stygian. After all, he was the one who had written it.
A gasp escaped the scholarly unicorn's mouth! "You... read my book?"
Another confirming nod came from the former princess. "Indeed I did, and I found it most fascinating. I for one could never imagine writing down the follies of my past for all to read. My time as Nightmare Moon," Her body language shifted ever so subtly as her tone took on a hint of regret. "Is not something I like to dwell on. Even though I've learned to conquer my inner demons, still they come back to me from time to time."
"I'm terribly sorry if I caused you any discomfort, Luna," Stygian sincerely apologized as he again bowed his head. "That was never my intention. But I knew I had to write about it! It nagged at my brain and wouldn't leave me alone!" A look of both bold determination and deep regret was reflected in his eyes.
Much to Stygian's surprise, Luna reached out a hoof to comfort him. "I'm not blaming you for anything or saying you did anything wrong, Stygian. It takes great courage to face your past demons, to confront and to reflect on who you used to be. We cannot ignore our past, even if we wish we could."
"So, what are you saying, ex-princess?" Stygian again pondered.
The alicorn explained. "I sense we have more in common than we might have suspected from our previous interactions, Stygian. Both of us were tempted by darkness and led astray, blinded by anger, jealousy and resentment towards others. Had we been willing to talk things out with those we thought had wronged us, we likely would not have fallen to the darkness. But we did, and it forced those closest to us to make hard choices. Yet in the end, we were both saved and granted a second chance."
Stygian nodded ever so slowly. "One I shall always be grateful for."
Luna's smile grew wider as she went on saying. "So it's up to us to make the most of that second chance. Our past can define our present and our future, if we let it. If we fail to learn from our mistakes, then we're doomed to inevitably repeat them. Your way of remembering your past is far more productive than the methods I initially used to keep me on the straight and narrow. But after a particular incident, I learned that just because we must live with our past doesn't mean we have to dwell upon it. Your book has inspired me, Stygian."
"Luna, are you perhaps thinking of writing your own biography about your past? About your time as Nightmare Moon?" Stygian sheepishly asked. "Because, if you were, I would be more than happy to lend you services in getting such a book published."
The former princess of the night blushed ever so faintly as she slowly said. "I... shall think about it. Either way, I think you have a promising future as an author. You might even eclipse A. K. Yearling as the greatest author of all time."
Stygian chortled as he threw back his head. "Oh, I don't think I could ever hope to hold a candle to her. I could never compete with something like Daring Do."
"Don't be so modest, Stygian," Luna reassured him. "Your talent for writing is incredible. Your attention to detail even more so. You may be a scholar now, but should you ever consider becoming an author full time you would have my support."