> Legends Long Forgotten
>  by nitelight
> --------------------------------------------------------------------------

> The Only Shadow
> --------------------------------------------------------------------------

Starswirl the Bearded prided himself on his vast knowledge of the magical arts and his ability to create and teach the subject to even the farthest reaches of the land. He had accomplished many things due to these abilities he spent time perfecting throughout his many years. He was a brilliant scholar, and even would go as far to call himself a hero of the land. 
With the help of another unicorn scholar, Stygian, he was brought together with a group of ponies to help protect the land from evil. The others included an eastern unicorn, Mistmane, pegasi Flash Magnus and Somnambula, and earth ponies Rockhoof and Mage Meadowbrook. Their many skills varied, just like the lands they were born from. 
With the help of these pillars of Equestria, they were able to defeat many a foe, the mythical sirens among the most notable. But one in particular was different from the others, and the ultimate sacrifice was made to banish a stallion who had once been his friend, along with the others he'd betrayed. Embraced in the evil grasps of the shadow, the downfall of Stygian led to their final battle.



The return of the pillars of Equestria had not been an uneventful experience. When Princess Twilight and her friends had freed them from their banishment in Limbo, the Pony of Shadows had followed along with them. Vowing the same as he had before his exile, he fled to the Hollow Shades, regaining his power to plunge the lands into eternal darkness. 
Luckily, his plans were stopped. Along with the power of the Pillar's magical artifacts, and the Elements of Harmony, which had grown in their absence, they were able to free Stygian, and the Pony of Shadows, the darkness' taken form, was pushed into Limbo, never to escape again. 
Starswirl had learned much from his experience with Twilight Sparkle and her friend, Starlight Glimmer. The times were indeed very different from when he had lived the prime of his life. The citizens themselves held a different attitude overall, their lands safer, more advanced. Over a thousand years ago, ponies treated him with the highest respect, now, he realized, he was nothing more than a legend, old writing in old books. The ponies knew of him, but other than a name in history, held no relevance. 
But there were two ponies in which he knew would still be alive, even after all his time spent away. He had been their teacher, almost a father figure to the two girls that would become some of the most powerful beings in all the world. He had questioned it at first, seeing as Twilight was an alicorn herself. But with the raising and lowering of the sun and the moon since his return, he had felt it. The trace of their magic was unmistakable. He had been with them before they had gotten their cutie marks, and their signatures were familiar to him almost as much as his own. He could feel Celestia in the sun, and Luna in her moon and stars. 
He wondered how much the sisters had changed in all his time away. They had grown up, no doubt. Grown into their positions as princesses and leaders of the land. He longed to see their familiar faces. The other pillars had their own lives to get back to, and he would never keep them from that. They also would want to see more of how the land had changed. He hadn't been sent to Limbo alone. 
So, when Twilight mentioned that it was best that they go back to Canterlot to inform the princesses of the defeat of the Pony of Shadows, he agreed wholeheartedly. They had taken the train into the capital city, since not everypony had easy means of traveling, either by air or via teleportation. He had not prepared himself for how much architecture would change in over a thousand years; the royal city of Canterlot was built on the side of a mountain, the golden spires resting at the highest point and looking over the lands beyond. The amount of wealth and prosperity topped even what he saw during Princess Platinum's rule in Unicornia before the Wendigo's froze the territory.
Wanting to get to know the princess who was now the element of magic, Starswirl had struck up a conversation with Twilight during their journey. He'd been skeptical and rude towards her earlier, and vowed to make up for that. In their conversation, he had learned that Twilight grew up learning under Celestia as her star student, even ascending to her alicornhood from her accomplishments under that study. One of her friends had informed him earlier that she had done so after finishing one of his own spells. Just what he would expect from Celestia. Her magical abilities had almost surpassed his own as a teenager.
Entering into the castle, they were greeted with guards welcoming them in. Perhaps Twilight and her friends were more well-known than he had thought. The interior of the castle was just as grand as the outside, the hallway up to the throne room decorated with multiple stained glass windows of accomplishments of the ponies. He recognized Twilight and her friends in a few of them. Even figures that represented Celestia and Luna appeared represented in battle. Some of these foes he did not recognize, though one figure that appeared in two windows held an oddly familiar aura. 
However, he did not have time to study it for longer than the time he walked by it. He would do so later. What sort of problems had the land gotten into? His scholarly mind was running with theories already. 
The throne room was even more beautiful than the rest of the castle, the open room full of depictions of the sun and moon, waterfalls flowing down around the throne that stood over the grand room. Standing at the other end of the room were two ponies in which he had not seen in what had felt like only days to him. Though what he expected them to look like was nothing like how they stood there, fully grown. The smiles that appeared on their faces lit up the already sun-brightened room. 
"Princess Celestia!" The voice of Twilight cut through the room, running up to her former mentor. "As you can see, we figured out Starswirl's journal!" Her voice was light, her smile evident in the way she spoke, filling in the sisters of the events of the past few days. 
It did not take long, however, before she got to the end, and to what was currently happening. She quickly stood out of the way, going to join Starlight and Sunburst to the side. "...But I'm sure you'd like to reconnect yourselves after all this time."
"I simply cannot believe how tall you've gotten!" Was the first thing Starswirl exclaimed. Last time he had seen her, she'd been around the height Twilight stood at currently. Now Celestia was towering over him easily. Even Luna's stature stood higher than his own. 
"Well, it has been over a thousand years. Will you stay here and teach magic once again? My sister and I have such fond memories of your lessons," the solar princess replied, leaning down into her younger sister's nuzzle of affection. 
"As long as you don't ask for those essays we owed you before you disappeared," Luna's deeper voice cut in, hiding slightly behind a silver clad hoof. The reaction of the room around was all laughter, knowing exactly what the princess was referring to. 
Keeping his short, while tugging at his beard in amusement, the old unicorn replied, "I'm not certain Canterlot is where I belong. The realm has grown, and I believe I'll have a look around before I settle in any one place." 
"And I long to see what had become of my home," Meadowbrook, from across the room, cut in. 
"I believe we all do," Mistmane was the one who replied, the other pillars nodding in agreement. 
"Then I hope you will return to Canterlot on occasion, and share the wisdom of your great experience with the next generation of ponies." 
"We would be honored," Starswirl replied in a bow of his head, "But if it is wisdom you seek, look no further than your own pupil. She showed me that the power of friendship is a magical force indeed. And, that in turning away from others, you hurt yourself as well." With his words, the pillars, and the bearers of the Elements, all gathered into a group hug. 



After their reunion, the pillars had been offered rooms to stay in for the night, before continuing onto the journeys of their homelands. While only mid afternoon, Starswirl thought it best to start with learning of what had happened while he was in Limbo. He had asked the directions to the archives to do such, an answer in which Twilight had jumped enthusiastically on. He had a feeling she had spent many years there growing up in the castle. 
Finding the exact date he was looking for did not take too long, with how often he'd spent in libraries before. He was able to make his way around the archives in only a few hours. The entire wing dedicated to him had occupied some of his time, admittedly. He was surprised how many of his works were transcribed and added upon throughout the years. But getting away from it soon enough, he started his way back to the room the princesses had granted him to stay in. Very generous of them, as he had insisted that it was unnecessary at first, but realized that the only other place he knew of in this advanced land enough was Twilight's castle, where he and the other pillars had stayed before. 
By the candle light, and later by the light of his own horn, Starswirl started his studies into the night. Meals had been brought to him due to the observations of the guards and maids that had been assigned to him. A stark contrast in how the everyday pony treated him. Here, he was a special guest of their Majesties, but that was not the same outside of Canterlot. 
Losing track of the time he was spending had not been hard. So many interesting events had happened since he'd been gone. Starting with the accomplishments of his old students. He had already gathered that the Tree of Harmony had grown the Elements, and from timelines, had grown to know generally how long it had taken for the tree to grow fully. As for the first defeat of the Spirit of Chaos, Discord, was done by Celestia and Luna using the elements, and petrifying him in stone for a millennium. He had heard of Discord before, tales of a darker time he was warned about when he was young. But much like wendigos, no one had given much thought to it until it became a problem and the world was in ruins. 
There were many more events like so, such as the fall of the Crystal Empire. It had not been a commonly traveled to land, due to its harsh weather conditions, but he had known its ruler before her usurpation. Princess Amore was known as the "Crystal Princess" during her role. One he came to know was occupied by another mare in this age. Princess Mi Amore Cadenza, or more commonly referred to as Princess Cadence. Her current role in Equestria was as Princess of Love, befitting of her name. He would have to meet her soon in his travels of the land. 
Sombra was a name he'd only heard in passing, a vague memory that did not occupy much of his time prior. But hearing of the actions the self-proclaimed King had done... he was proud of the princesses. He had, after all, taught them almost everything he knew in how to handle such situations. Then again, where had that got him with Stygian?
Shaking that off, the other most notable event was that of a centaur who had been thrown into Tartarus named Tirek. A creature who sought to steal magic for himself was the worst kind of villain. A pony's magic was their lifeblood. 
A few others, such as the Griffon Wars or the land disputes with dragons were interesting, yes, but nothing much was to be said about them in such ancient history. By the time Starswirl had decided that it was time to take a break, the moon had already risen high in the sky, almost at its peak. 
Since he was already up, and in desperate need to stretch his legs, he stood to go out for a walk around the castle. Perhaps he could run into another nightly scholar, an astronomer, perhaps, that he could converse about the stars with. As his namesake, they had always been fascinated by them. And in a thousand years, many changes had no doubt occurred in the skies he once knew like the back of his hoof. Charting them would prove entertaining if he ever found himself with nothing else to do, though unlikely to happen in the next few years, at least. 
What he should have considered, however, was a certain night princess also being nocturnal. Starswirl stepped out to a small pond out on the grounds, the full moon clearly overhead. It was a peaceful setting, the city below only disturbing the serenity when the wind blew up from under, carrying past sounds of the late night's activities. The only other sound was of someone clearing their throat. Turning his head, the sorcerer expected to find a gardener, or a guard, at least. But alas, the very beautiful, and glowing, might he add, form of Princess Luna stood before him, bathing in the light of the moon of which was her destiny. 
"I hope I am not interrupting your thoughts."
"Not at all," he chuckled, motioning to the spot next to him on the ground in invitation for her to sit next to him. "I always welcome company in the late hours. Night, after all, is when the most art is created."
"I was almost worried when I could not detect your dreams along with your friends earlier this eve," she responded while taking up his offer, long tail spilling around her form and stopping its ethereal breeze. "But I see that I had no reason to. Up reading on what you've missed, I presume?" Her voice was light, smooth. A stark contrast to the more high-pitched, childlike voice he was used to putting with her face. She had only been a child, then. Now, she was a fully grown mare. He was almost like a proud father, even through knowing only a few of her accomplishments. 
"You know me too well, I fear," which earned a chuckle from both parties. "Many things have happened in the time I have been gone. I had simply been wondering how the land had fared before the Tree of Harmony had grown to protect it. And perhaps I got too engrossed in my research." 
"And how far from your disappearance have you gotten in your historical advancements?" Whether he noticed the hesitance in her voice or not, he did not mention it. 
"As of now, after the events of the conflict of Lord Tirek and yourself and your sister. So many foes, and I was not there to help either of you." He knew that they were fully capable of taking care of themselves, they had proven that easily in their actions, it was his job to protect the land from these threats. 
"'Twas no trouble, Lord Starswirl. I assure you that we were able to come out on top of any conflict we faced." 
"Of course. But I must ask—I can see what's happened in the history texts—but what have you been up to this past millennium?"
Luna seemed to pause at that question, her posture stiffening. This only made him more curious. He could physically see that the world around him had advanced spectacularly, but he wanted to know what Luna had done in her free time. Had she just spent her time ruling? Made advancements in her fields of astronomy? Fallen in love, even? 
"We— I have spent most of my time with my moon... but if you'll excuse me, actually, my duties are calling me back to work. There is a nightmare that I must attend to urgently. I apologize. But we shall see each other again before you depart from the city, I hope?" Her words came out quickly as she hurried to stand up again, before walking off with a rush in her steps. She seemed nervous, as if she hadn't anticipated him asking that question. Then again, perhaps it was the nightmare which she sensed that caused her to be in such a rush. 
With her moon, she said? It had made sense that most of her time had been spent dedicated to something she was so close to. But she seemed almost uncertain. In a rush to get away from the conversation. Of course, he understood that her dream walking was a very important part of what she did as princess, but never had he seen this in relation to it. She had been so proud of herself when she had created the spell when she was young. 
No matter. He was sure that he could ask her more on it later when she was not so busy. Deciding that he had had enough of a break, Starswirl made his way back up to his room, intent on going back to study up a few more centuries before retiring for the night. 
In the time that he was gone, someone had come into his room to organize and tidy up his room. And they had resupplied his candles. It was almost as if the universe was telling him that continuing his studies was what he was supposed to be doing. Yes, the past few days had been quite intensive in their activities, but studying was calming for him. A way to use his brain in ways other than combat that were still useful. 
Most of the next few centuries were uneventful, and he was almost about to call it a night before something caught his eye. It was not a name which he recognized from tales of even more ancient times than him. The Legend of Nightmare Moon. 
He read the story with enthusiasm, needing to cross-reference with the Elements of Harmony on a few occasions to get the full story. This tale was, after all, how they had gone missing for a thousand years and become an untold legend. 
However, the specifics of the story were what pulled him in the most. It told of a story between two sisters, elder of the day, and younger of the night, who had gotten into a fight started with the younger's jealousy. Transformed from her emotions, the younger sister turned to the darkness, turning into the legend's namesake, Nightmare Moon. During their battle, the elder used her powers, and the elements, to banish the evil to the moon for one thousand years, in which after her time was up, the stars would aid in her escape, and she would bring about nighttime eternal. 
It sounded almost too familiar. Celestia and Luna were sisters, day elder and night younger. He knew them to fight and get jealous of one another. Siblings fought, those two especially, always in contest with one another over anything from the smallest conflict, to literally moving the sun and moon. 
But being banished to the moon for a thousand years... Celestia would never do that to her younger sister. Luna, sweet Luna, could never turn against her like that and take down the kingdom alongside her anger. The fight seemed likely enough, though. But he could never imagine that one would escalate that far. But Luna did mention that she had spent a lot of her time 'with her moon'. Could it be..? No. He would not jump to conclusions. Best to ask about it in the morning before making assumptions. 
After reading that legend, Starswirl decided that it was probably best to get some rest. There was no use in continuing his research when his mind was overclouded by the thoughts of what he'd read. He only wished that Luna in her dream walking would not come across any dreams of his that proved worthy of her intervention. He would not want to face her like that with his thoughts the way they were now. 



Starswirl awoke before the sun. Despite his weary, and frankly old, bones protesting, he had never been much of a long sleeper, preferring to only do so when necessary and devote most of his time to his studies. Since he had done so the past few days, waking up in an unfamiliar bed should not surprise him, but he had to keep reminding himself of the events that had happened the past few days... few centuries, that had gone past in the blink of an eye. 
Straightening himself out, putting on his cloak and hat, and lazily brushing through his beard so no large knots would disturb him, he was ready to continue on with his day. Perhaps instead of facing the problem straight on, he would ask Celestia. She would be up this early, getting ready before she was to raise the sun with her alicorn strength. 
Briskly trotting his way through the halls of Canterlot Castle, it did not take too long before he reached the doors of Celestia's office. That is where the guards he'd asked said she would be this early in the morning. Perhaps more of his bad habits transferred to the girls than he had realized. Though, scolding her for getting to work this early was not something he could do without being hypocritical. Bringing up a hoof to the polished and ornate wood carvings of the door, he knocked, waiting for a response. The guards paid him no mind. 
There was an audible "come in", followed by a golden yellow aura surrounding the doors, opening them slightly for his entrance. Pushing them the rest of the way open himself, he caught a glance around the decorated room. Far more lavish than anything he had seen during his time, but not too overcrowded that it was gaudy. 
"Starswirl! What a surprise to see you awake so early. You slept well, I hope?" Celestia's voice cut through the room, her good mood evident in her tone. Her voice was much brighter than her sister's calmer one he had witnessed the night before, seemingly retaining some of its childlike innocence. Though he knew that was only the tone she wished to portray, as the pony in front of him was arguably more mature than he after a thousand more years of experience to back her up. 
"I did indeed, no need to worry."
"That's good to hear. I'm sure Luna took extra care to make sure you and your friends slept without fear. What brings you here, though? Did you need assistance with something?" She had looked up from her paperwork by now, head tilted slightly to the side in curiosity. It truly was funny how many little quirks the sisters shared. 
"Actually, mentioning your sister, Luna is the reason for my visit. I have some questions that I wish to ask. I know Luna likes to keep to herself, and I hate to come across as abhorrent."
"Luna? Whatever about? Has something happened?" 
"Not in recent years, no. But I have concerns of a legend that I have read." The princess tensed up at that. The same reaction that Luna had had when he mentioned his research last night. "I do admit that I could not wait long before diving into the history of the land and seeing what I have missed. And I must ask, as I am sure you can guess by the way you have responded, is my hypothesis of the legend of Nightmare Moon correct?"
The room fell into silence. Celestia's expression had fallen, averting her gaze from the sorcerer's. The only motion in the room was her constantly flowing hair in its ethereal breeze. He knew it was not an easy subject to bring up, but Celestia's tongue was easier to coax into conversation than Luna's. 
After minutes had passed in silence, a sigh from the solar diarch cut it short, her eyes closed, brows furrowed ever so slightly. 
"Yes." A quiet, strained, chuckle fell from her lips. "Leave it to you to only wait a few hours before finding it out. Have you confronted Luna about it?" After a shake of his head, she stood up, walking over to the door. "Then I would like to show you something. Follow me." 
Her height towered over him, long legs making only a stride of hers two of his own. No words were exchanged between the two of them during their walk. And what she wanted to show him, he did not know. His gaze shifted over to the low moon steadily making its way under the horizon from the tall windows that adorned the walls, his emotions uncertain. How did he feel about this? He never came to a full conclusion, hopping from one side to another with them. 
She soon enough came to a stop in front of the stained glass windows in which they had passed by the day before, leading up to the throne room. Celestia was standing in front of one that had caught his attention earlier. The figure it held had the cutie mark of a moon, mane full of stars, serving only to confirm his theory further. On the lower side of the picture, were Twilight and the other element bearers, using said elements against the foe. 
"This shows the most recent victory over Nightmare Moon." The sigh was prominent in her voice, turning to the other side of the hallway, where a similar picture was displayed on the window. This time, Celestia in place of Twilight and the girls, wielding the elements herself. "And this is the first battle against her." 
"But I do not understand. How could this happen? Luna... you two were so close. Whatever could have happened?" It was something he could not wrap his head around. Yes, he had seen them fight, but never before to that magnitude. 
"It was my fault. I was a horrible sister to her. I... drove her to become that thing. That monster." Celestia shook her head, her demeanor shifting. This was clearly something that affected her negatively. "She got angry, rightfully so, at how she was being treated. And I ignored her every time she tried to ask for help... They slept through her nights. Even after she spent so much time perfecting them. And during the summer solstice, she raised the moon to cover the sun— one thing led to another, and I did the first thing that I could think of, and banished her to the moon for one thousand years. It was wrong. I should have tried to talk with her more." 
It was not hard to hear how she was choking on her voice, tears threatening to fall from overwhelming herself with emotion. She was fighting to not let them show. He did not know how hard it was for her to confess to him. He knew how much she had looked up to him. 
But, then again, he had done the same thing to a close friend of his. Stygian had gotten angry at how ponies were treating him, and took matters into his own hooves. He stole artifacts from the pillars, Luna stole her sister's light of the day. Stygian was overcome by the darkness, and his form changed along with him, possessed by what he called "The Darkness". Starswirl and the pillars refused to listen to him while he vowed to steal the light from the world. And for his actions, banished him from the coherent world. 
He had done the same thing. It was how he dealt with most evil creatures that he fought. He did not believe in reformation until just recently, and that had taken Twilight's help, along with another reformed mare, her student, Starlight. 
That begs the question, however: would he have done the same thing as Celestia in that situation? Would he have banished Luna so far away? Could he have done that to a sibling? Or to a daughter, as he sometimes thought of them as? He was their teacher, after all. He'd been the one to teach her, and put it in her mind that that was the only solution in such a situation. His earlier comment of, 'Once a villain, always a villain,' was now coming back to bite him. He'd already mended one old relationship of the past, and perhaps it was time to do that to another.



For the better part of the day, he had spent working through his mind to find a solution to his problem: how to talk to Luna about the legend. Celestia had spent the better part of the millennium alone, and Luna... who knew if she even remembered her time away. In Limbo, time did not pass, and upon his return, was as if nothing had happened. 
Seeing how it had affected Celestia, her calm disposition falling the moment he had brought it up, he was afraid to see how Luna would react. Whenever she had messed up as a filly, she was quick to apologize, to shut down when she did wrong, or to get angry, if she thought she was in the right. How had something of this magnitude affected her? Even briefly mentioning his historical pursuit earlier had made her tense up. 
He had spent some of his time distracting his mind, asking about how the land worked in all its modern facilities. Some of the other pillars had already set off in search of locating their old homes. Mistmane and Flash Magnus had plans to stay for the day still until exploring the land. He too had places that he wanted to journey to, but he could not do so until accomplishing what he needed with Luna. 
This, of course, would have been finished much sooner if she were not nocturnal. Due to her nightly duties, Luna slept during the day, and he had not wanted to keep her up longer in the morning after he had talked to Celestia and she raised the sun. It was best to find her in the night, like he had before. 
It was one of his least productive days in over a thousand years. He had not remembered the last time he had not been working from dawn to dusk. But thankfully whatever he had been doing had distracted him well enough that he was surprised when he saw the moon being raised by a certain lunar princess from a balcony higher in the castle. 
However, it took longer to locate her more specifically in the castle proper. Asking the guards the princess' whereabouts had taken longer than it should have. This castle was much larger than the one in the Everfree that he was used to. But she was eventually found near the astronomy wing, thestral guards on either side of her, helping to pull her out of what seemed to be a particularly nasty nightmare. There were not many times he was able to witness her dream walking, and therefore was unable to determine much more than what was clearly visible. It was far more complex than he had originally thought.
The two stallions were eventually waved off, however, once Luna gained her composure once again. What had been going on that it had taken that much out of her? He soon figured that he would never get that answer, as her expression upturned into a gentle smile in his direction upon noticing his arrival. 
"It seems as if we have been running into each other often these past nights. Did you come to see the astronomy tower?"
"On the contrary, actually. If you have the time, I would like to talk."
"Oh! Ah- yes. I have some time before I'm needed anywhere. What would you like to talk about?"
The guards that had moved away from her sides were still watching their every move. This, however, was a conversation best done in private. He knew they were looking out for her, especially after the event of such a nightmare, but they did not need to be staring at them as intently as they were. 
Luna took note of his behavior and glanced towards them, waving them off as she turned to motion that they enter the tower. It would likely be empty at this hour, the day shift retired for the night, and the night shift yet to clock in for their activities. 
"I talked with your sister this morning," he said, as the door behind them was closed with the blue aura of the princess' magic. "I must ask you about Nightmare Moon."
Her response was similar to how Celestia had reacted. She stopped in her tracks, averting her gaze, form threatening to deflate, but holding her ground. He knew this would be hard to breach into. Slow and steady was the best case he could make. 
"...And what are your thoughts on the event?" She had risen her guard already, voice hardened and tense. 
"I do not have any say on the matter. I only wonder how such an event could occur. I would like to hear your perspective, as listening is all I can do." 
"I was foolish. There's nothing more to it. I made a mistake that cost me everything. Not that you would understand." The last part had mostly been mumbled, almost as if she was only thinking it, not actually meaning to say it out loud. He had experienced many failures in his life, though none as drastic as costing him to be banished for a millennium. What he had been banished for was not for his own wrongdoings. Partially, anyway. 
Hearing three different sides of the same story was enlightening, however. The legend had said she was overcome by jealousy and taken over, Celestia had said she had ignored her sister's worries of the ponies ignoring her work, and Luna had said it had been her own fault, that she misjudged a situation for the worse. It was hard to keep the conversation going, with the amount of tension in the air, but they needed to get it out. 
"What would you really like to know, Starswirl? You're a scholar. Are you trying to study a phenomenon that you've only seen in Stygian so far? Surprised to see that it isn't that uncommon for it to happen to somepony? Or is it that you want to tell me how you feel? Your life was dedicated to vanquishing the darkness, after all, was it not?" She sounded calm. Too calm, for the ire he felt radiating off her form. He was not good at treading lightly on sensitive subjects. 
"As I have said, I wish to know how—"
"Elaborate on that. How we fought so? How I turned to the darkness? How it felt to be possessed by that parasite? How it felt to be imprisoned in my namesake for a millennium for fighting back in trying to defend myself? What is it? I know you want to ask."
She was right. He was curious of all of it. He did not understand how she grew up to understand the intentions of others so well, though that answer was most likely staring him right in the face at the moment. Luna had learned from her mistakes. He had only started to in the last day. 
"You're brilliant, Starswirl, but you don't understand what it's like in the opposite position. Just like Celestia, you only know what it is like in the spotlight. Having those love you for everything that you do, and casting those out who try to get the credit that they deserve on your side."
Twilight had already filled her and Celestia in on what had happened with Stygian. Was she disappointed in him? That was very likely. She had looked up to him when she was younger, learning great feats of magic through his knowledge. He had helped her to earn her cutie mark of the moon which she cherished. The stories of Luna and Stygian's downfalls were so similar that it stung. 
A look flashed across her face, putting together a fact in which she had missed earlier. He hadn't even been able to get a word in, but her points were correct. He did not know what it felt like, and had acted on assumptions. 
"She learned it from you... Thinking about it, you did the same thing, didn't you? You banished Stygian 'for the greater good', but was that really your only option at the time? Did you have to use that much power to seal it away rather than try to actually fix the problem?" The emotion was finally showing in her voice, so many that he did not know if he could name them all. It was all too convoluted. 
"Luna, I understand that my methods were not the best way to go about things, but you have to understand—"
"No. Tell me, Great Starswirl the Bearded, would you have done the same thing to me if you were still around? If you hadn't banished yourself along with the Pony of Shadows to Limbo, would you have banished myself as well for what I had done?"
That was a question he was afraid of answering. No answer could ever be confirmed in totality. Going by his morals at the time of doing it to Stygian, it was very likely that he would have. Awful as it was, the answer was yes. It was how he knew how to save the world from evil forces. He had learned that it was wrong now, but it was a thousand years too late. 
Not even waiting for him to voice his answer, she likely deciphered it from the expression on his face, her own hardening more, Luna's wings gradually fluffed up to the point they were at half mast, already sporting an almost predatory, guarded stance. 
"...Then I am almost glad that you were not there when it happened. Perhaps I would have joined the Pony of Shadows in Limbo and would not be here today." She let out a breath, trying to calm herself. "I know how you feel about such creatures, Starswirl. I know that Twilight has helped you see the error of your ways. But that does not help your case. Had she not shown you that, if anything, reformation, even a conversation, can do wonders? Neither of you even tried such a thing. Much like Stygian, Twilight saved me from my Nightmare. She was able to pull me out of it and give me another chance. I am much happier with my life now than I ever have been before."
Change was something that he was still getting used to. And dwelling on the past was something Luna knew more about than anypony. 
"And that I can clearly see, Luna. I may never understand what it is like to be on the opposite side, or to ever know how you felt the need to succumb to the evil in your heart, but I know now that I was wrong. Saying it was just how things were is never the right answer. I still do not know everything, much less on how to properly talk on such things as reformation. I once thought that once evil went into the heart, it could never be removed again. I am still learning from my mistakes with the help of Twilight. It took banishing myself to Limbo for over one thousand years to even start to figure out how wrong I had been. I do know that saying a simple apology will not suffice, but I will say this: no matter what happened in the past, no matter what you had done, intentionally or through the blinders of anger, I still love you. I raised you and Celestia in the ways that I grew up. I taught you what I knew on the sun and the moon, as they were yours to behold. We have both made mistakes that we regret terribly, and no amount of words are proper enough to reverse them or make it better. All we can do is move on and continue to improve upon ourselves, taking what we know now into action to potentially improve our future. I love you, Luna. I do not care what you have done or how it came to pass. All I want you to know, is that I will stand by your side, and support you throughout everything that you do. You hold so much love in you, and I would hate for it to be suppressed under the sheer falseness that are your insecurities. You are like a daughter to me, and yet I have not treated you like the family that you are to me."