The quiet echo of your own footsteps, your leather boots clacking against the rough, mossy stone is your only companion as you venture deeper into the ruin you have chosen to explore today. One hand rests comfortably on the pommel of the long, thin blade you carried with you, the one you'd stumbled upon the day you arrived in this accursed world. Back home it would have been somewhere between a rapier and cutlass, the blade thicker than your average fencing weapon and well suited to slipping past an opponent's guard, and if you were lucky, past his ribs too.
You'd never had to use the blade on anyone since you arrived in Equestria, but you practiced with it every day out of sheer diligence. You never knew when one of those damned unicorns would try something, or one of Celestia's guard would try to haul you back in front of the contemptible mutant of a Princess.
You spit on the stones at your feet in disgust, your torch flaring a bit as you jostle it. She was the reason you were here. Her and her magic had ripped you from your home and cast you into this place. She had sworn up and down that it was an accident, that she hadn't meant to do it, but you didn't believe her. You hated that white pony more than anyone else, and the only thing you hated more than her was perhaps magic. After all, that unnatural force was what had let Celestia do what she did.
Your bitter reminiscing is interrupted by your arrival in a large, open chamber. If you didn't know any better, you might think that stone table in the center of the room, at the very edge of your torchlight, was some sort of sacrificial altar. Having no interest in what was likely to be more magic, you turn to leave. Mustn't waste time when there was treasure to find.
And then your torch caught a flash of metal from atop the table. Intrigued, you approach and are thrown for a mental loop as you see your initial assessment, however sarcastic it had been, was dead on. Before you sat a squat stone table, replete with images of the sun (you note this with considerable distaste), quite a bit of dried blood, and the chained body of what was unmistakably the same sort of creature as the hated Princess, if the wings and horn combo was anything to go on.
Your torch had caught a bit of the glittering silver chains that held the corpse, still bright and shining despite the age of the place. More magic, no doubt, but if you were careful and sold to the right pony, these chains would net you a fair few bits. At least a week's worth of meals, you assumed, as you reach out to grab one of the chains.
You can't.
It's as if you had suddenly become magnetic and the chains held an exact opposing charge to yours. Your hand simply stopped when it got too close, no matter how hard you pushed. You slam your fist down on the table, infuriated by being denied meals by the same hated force that had dragged you here.
Your eyes wander over the corpse as you ponder your next course of action. It was evidently a mare, judging by the long mane and tail. You were ashamed to say you knew enough about ponies by now to be able to tell that much. Her filthy coat was a pitch black under the dirt and blood, but it was patchy and stretched over her bones. It looked as if she had been denied food for a long time before she was killed. Her horn was long and still razor sharp even long after her death. You surmise that when she was alive she might have been very beautiful and imposing as ponies go, her larger than average size lending her an intimidating air.
With a wry smile you note that you sympathize with the unfortunate mare. She was evidently forced from her home too, but didn't get as lucky as you had. A sudden idea strikes you and your eyes flick to her flank, looking for her cutie mark as some way to identify her. You're surprised to see the image of a crescent moon, and you wipe away the dirt from her coat to see it more clearly. Even after this long, it was still somewhat soft. Perhaps this mare was some opponent of Celestia's? The white princess' emblem WAS the sun, after all.
You are so engrossed in your inspection that you fail to notice the corpse weakly turn her head and open her eyes, staring at you with milky white pupils. Her lips part and the nearly silent croak that passes between them is enough to send your hand scrabbling for your sword. This mare was still alive?! What had Celestia done to her?
Once you had successfully gotten your heart to stop trying to leave an imprint of itself on the inside of your ribcage, you very cautiously step back over to the altar. The mare was unmistakably staring at you now, and seemed to be trying to speak. Her forelegs pressed weakly against the manacles as she tries to lift herself even a little from the cold stone.
Your emotions at seeing this pitiful display run quickly from sadness to blind, consuming fury. Whatever this mare had done, it did not warrant this. Celestia WOULD pay for this, but for now your only concern was the mare in front of you, who seemed to finally have found what remains of her voice.
"Water..." Of course! She had to be terribly thirsty after all this time. You hastily scrabble through the bag at your side, pulling out a canteen and popping off the lid. Your hand gently lifts the mare's head so she can safely drink, and she drains the whole canteen in short order. Only after she finishes do you dare speak.
"Can you hear me?" She offers a weak nod. That was a good sign at least. She was lucid. Your mind races from question to question, trying to decide what to ask. You finally decide on a simple "What can I do to help you?"
She doesn't answer for a long moment, and just when you think she may have actually died, there is a long, shuddering breath from her.
"Don't... Leave. It's cold..." And just like that, the fury was back. You were human, dammit! No one was going to stop you from breaking those damned chains, magic or no magic.
A lot of things had been said about your temper since you were a child. But today it serves you well. You draw your blade and slam it into the magic barrier around the chain on the mare's left forehoof. A resounding crash echoes through the chamber, but you keep slashing at it, blood pounding in your ears.
It seems whoever enchanted the chains didn't count on the tenacity of an enraged human being, because just when your arms are about to give out from fatigue the manacle shatters like glass, a few shards hitting you in the face as your blade slams home. The mare looks to you, to the manacle, and back again. She doesn't seem to believe her own eyes, and you don't blame her. You fall forward a bit and rest against the altar, gasping for breath. It is her voice that breaks the stillness after a few moments.
"Thank you." Whatever breaking that manacle did, it seems to have helped considerably. Her voice is much stronger now. Still gravelly and weak, but no longer so faint you had to strain to hear it. "Celestia will be furious with you for this, I hope you know... What are you? I can barely see, but you don't look like a pony at all."
You scowl at the mention of Celestia. "I don't really give a damn what she thinks, my dear. Anyone who does something like this to someone else deserves to suffer twice as badly. As for what I am, don't worry yourself over that. I'm the woman who's going to fix this. That's all you need to know, all right? What's your name?"
She considers this for a few seconds, before drawing in another slow, deep breath.
"Nightmare moon."