"Pardon me, friend. But is this the former home of Starlight Glimmer?"
Double Diamond didn't recognise the voice when it spoke to him, but it sounded friendly enough and he turned with a smile on his face to greet this newcomer to their little village. However, as soon as he did so, his eyes widened considerably, for this was not just some random pony coming for a visit, but one far more unexpected. "P...Princess Celestia?!" The white stallion fell to his knees, bowing respectfully. "I can't believe you'd come to a place like this! We're honored to have you here!"
Celestia, who had been through many centuries of ponies acting this way towards her, offered a polite smile before silently gesturing to the grovelling pony before her. Double looked to her and, after a moment of hesitation, got back to his hooves, brushing himself off. Celestia glanced around, seeing many a stallion and mare whisper excitedly to one another, no doubt because of her presence here. Yet there was something else to it. It was as if she were scouring the village for somepony in particular. Somepony she had yet to see. And so, when her eyes failed to find what she wanted, she again looked to Double. "I thank you for you kind welcome, Mr Diamond, but I'm actually here to see somepony in particular."
Double nodded, his smile far wider than before. "Oh! Certainly! Just ask and I'll take you right to them!"
Celestia gave a slight bow of her head in thanks for his offer. "It's my understanding that they're rather new here. Would you know of any recent additions to your village?"
And it was with that question that Double's smile faded, but only a little. He clearly didn't want to appear in any way uncomfortable in front of her, but it was obvious to Celestia that this wasn't something he wanted to be talking about. "Um...yes, we did have somepony new. But he's not really the friendliest of types."
Celestia, forever maintaining her poker face, enquired further. "Oh? Do tell."
Double sighed. "He's not bad exactly, but he kinda keeps to himself. Never talks to anypony and mostly just does his chores before staying in his house all day."
Celestia again looked around the immediate area. "Would you care to tell me where I might find him?"
Double, never one to refuse a request from royalty, looked over his shoulder, pointing right down the main street of the town. "You'll find him just out of the other side of the village. Can't miss it."
The Princess gave him a smile of her own. "Thank you. I appreciate it." She watched him give a second bow to her before beginning her walk forward. Double didn't follow, and nor did anypony else, even as she passed them by. Celestia's ears continued to pick up all the usual chatter and gossip that tended to accompany any surprise visit she made to a place, but her focus was squarely on her destination. House after house she passed, and before long she was right where Double had told her about, leaving the furthest end of the village and heading just outside of it. True to Double's word, there was indeed another house out there, though it would have been more accurate to call it a hovel, given the size. Already, the Princess knew he wasn't within, since she could hear sounds coming from around the back.
Making her way there, she saw him. A unicorn stallion, dark in both fur and mane, his back turned to her. With his magic he was levitating nearby logs onto a large flat stump in front of him, before taking hold of a nearby axe and chopping them in a single swing. Though she'd normally not want to interrupt somepony when they were making firewood for themselves, today was not the day for formalities, and so Celestia took a single step forward and cleared her throat.
Instantly, the stallion stopped mid-swing, and though he did not turn to look at her, he spoke all the same. "I don't get many visitors."
His words were short and to the point, with a relatively deep voice, and one that Celestia knew well already. "I thought at first I might have been imagining things when I sensed you. But it seems my intuition is still as sharp as it used to be."
The stallion still kept his face away from her. "You've come to the wrong place, Miss. I don't know you, and you don't know me."
Celestia's eyes narrowed. "We both know that's not true."
Few would have heard her speaking that coldly, but not this one. Instead, the stallion sighed, swiftly planting his axe right into the next log in-line, before finally turning to face her. The image Celestia now saw was more than a little different from the last time she'd seen him. No armor, no cape, no bright red horn. He was, for all intents and purposes, a regular-looking unicorn stallion, if a bit harsh in his features. And those features made it clear he wasn't happy with this unexpected visit. "So...you found me. I wondered if my presence here would be known to you eventually."
Celestia took a cautious step forward. "There are few places in this nation that I do not keep an eye on, Sombra."
The dark unicorn frowned to her. "So...should I expect your sister to appear out of nowhere to join you in vanquishing me? Or perhaps your beloved apprentice and her friends?"
Slowly, Celestia shook her head. "No...it's just me today."
Sombra raised an eyebrow. "Brave of you. Or foolish, given how things went during my last revival."
The Princess looked him over, her voice betraying her understandable curiosity. "Yes...and how exactly did you revive this time?"
For the first time in all the long years she'd known him, Sombra actually appeared to be at a loss on that one. "That, I cannot say. One moment I am facing down he combined powers of Twilight and her friends. The next...I awake in a place I'd never been." He looked to the side, pointing to some nearby mountains. "Over there, amid the crags and jagged rocks."
Celestia regarded the place, then looked back to him. "I'd have expected you to try your hoof at seizing Equestria again. Not...chopping wood."
Sombra grimaced, looking to his sizeable pile of firewood. "Time...has a way of changing one's perspective."
Celestia looked to him with more than a little incredulity. "Am I to believe that you, upon returning to the world of the living, have simply decided to...retire?"
A moment of pondering that notion led to Sombra giving out a quick chuckle. "An odd prospect, I'll grant you. A unicorn famed the world over for his desire for conquest and subjugation...now choosing to live a life away from everypony and everything." He paused, but only for a moment. "If there is one great teacher in this world, Celestia, it is failure."
Even Celestia couldn't help but smirk to that. "Then I'm sure you must be very well-taught by this point."
Ignoring that, though still frowning to it, Sombra began to explain himself. "In those ancient times, I sought dominion over the Crystal Empire. And though I succeeded, my efforts led you and your sister to me, and thus my downfall was assured." He glanced away. "When I returned, I was felled again, and not even by alicorns this time, but simply by a young dragon and the ponies I once enslaved." His frown deepened. "When a third time I stepped into the fore, I reached further than ever...yet still I was defeated." A long sigh escaped him. "Three strikes...and I am out."
Celestia's face, if only a little, softened to him. "So...you gave up?"
Again, Sombra did not look to her, instead staring at the distance, to the horizon. "A life of conquest and war brought me only to ruin. Dominance earned me naught but enemies. Ambition of rulership was always snatched away from me. Were I to try such a thing for a fourth time...there is no doubt that I would simply meet the same end as before."
His ancient foe considered those words. "Well...I cannot call you wrong, O fallen King."
There was a time Sombra might have raged against such a thinly-veiled insult, but that time was not now, and instead he just sighed again. "A life like this? Away from others. A life of quiet. I'd never considered it. Never wanted it. Yet here I am. Perhaps there is value in this simple life that so many other ponies live. If nothing else, I might not end up in the same dark place."
Silence passed between them, and for a good long while too. Whether Celestia believed what he said or not was hard to say, given how legendarily good she was at hiding her feelings on such matters. Yet as her old foe just stood there, never once showing any signs of aggression or bitterness towards her, there eventually came a moment when the Princess turned, once more looking to the mountains where this stallion had again returned to the world. "Perhaps fate decided you were finally ready to be allowed your freedom."
Sombra snorted. "Fate? I don't believe in it."
Celestia looked down to the ground for a moment. "Perhaps not. But whether through some higher power or simply some fluke of the magical forces of our world, you live again. Yet you seem to have chosen peace instead of war." A quick giggle came to her. "I honestly never would have thought you capable of such a life."
Sombra rolled his eyes. "We are of a kind in that regard." But his face became more steely afterwards. "Though choosing a quiet life will do me little good if I am to spend it in a prison."
Celestia looked to him with seriousness. "Prison? And why do you believe that will be your fate?"
Sombra actually seemed amused by such a question. "Come now, Princess. We both know why you are here. You came to see if I lived again, and if I did, to ensure I could no longer harm Equestria." He looked around. "Now that you've found me, I have no doubt that you'll call in some reinforcement to ensure I am apprehended for my past crimes."
The Princess nodded solemnly. "It is true. Were you still walking your old path, that is indeed what I would have intended. But instead, I find you living by yourself, not wanting to be bothered by anypony. You came here, to a town few even know of, and chose isolation even within a community like this one." She took a deep breath. "You were right, Sombra. You have committed many crimes, and there are likely few who would ever forgive you for them. But it could be said that you have already paid for those crimes with centuries of imprisonment, and even death...twice."
Sombra arched an eyebrow. "For the record, the deaths hurt worse."
Celestia ignored him. "I see not the rampaging beast who needed stopping...but instead a stallion who seeks to live alone. So..." She turned, beginning to walk back to the town proper. "If that is what you wish your life to be, then that is what it shall be."
Sombra looked to her, utterly bewildered. "You...you mean to just leave me here? No fight? Just...just walk away?"
Celestia, keeping her back to him, answered. "Do not mistake me. I have no intention of allowing you free reign. There will always be eyes watching. Peace may be something I'm willing to grant, but that does not make me a fool who will simply trust blindly." Slowly, she looked over her shoulder narrowing her eyes to him. "Should you threaten Equestria again..."
Her tone made it clear that this was not freedom, but a watchful probation, and while Sombra might have once chaffed under such a suggestion, now he simply sighed, giving a single nod. "If those are to be the terms of this new life...then I can accept them."
Again, Celestia nodded. "In that case, I shall take my leave. Farewell Sombra. I wish you well in this new home."
Though it surprised him greatly, Sombra knew she'd meant that, and so stood in silence as she Princess of the Sun continued to walk away. Eventually, he could see her no longer, and so he was once more alone. He preferred the solitude of course, but the meeting had left him with much to ponder. "So...this is life now. Free to live alone. Always watched, with my enemies ready to strike the moment I stray," he said to nopony in particular. As the notion sank in for him, he glanced around, wondering where Celestia might have her eyes here. Were they among the townsfolk? Were there perhaps guards high up in the clouds ready to swoop down at him? Whatever the case, he knew he had nothing to fear. He had no intention of making war again, for he knew well the only fate that road would lead him to. And so, as he sat upon his log-chopping stone, he allowed himself a moment to chortle. "Well...beats being killed at least."
Author's Note
A long time ago, I read a comic where, by the end, the villain had decided to give up on a life of evil after many failed attempts to achieve ultimate power. Instead, he settled down to become a farmer, and that idea really stuck with me afterwards, that a bad guy would just quit after his failures and try for a quiet life. Thought I might try something like that here 
