Remnant of a Nightmare

Night Stone Castle. An imposing symbol of one of Equestria's most notorious enemies and of one of the country's darkest times. Built in secret underground by diamond dog muscle and funded by the cult known as The Children of Nightmare, it was raised to the surface by Nightmare Moon herself once the cult was able to restore her to her full power. From this midnight-dark edifice the alicorn of nightmares ruled over Equestria with an iron hoof,  defeating both Princesses Celestia and Luna, banishing them to their respective celestial bodies, and fulfilling her dream of night time eternal.

This was not to be Equestria's ultimate fate. Before returning to power, Nightmare Moon had been reborn as an innocent filly. The first time her cult had tried to resurrect her, the spell had been disrupted by Princess Celestia. The unintended consequence had been Nightmare Moon indeed reborn, but in the body of a young filly. A young filly with no memory of her previous life as the mare of darkness. Found by Twilight Sparkle and brought back to Ponyville in the hopes of her true identity being born out, she made friends, became part of the community, and even, secretly, was adopted by Twilight herself, who had renamed her Nyx.

Then the Children of Nightmare found her. Spell Nexus, leader of the cult, used his influence as the headmaster of Celestia's School for Gifted Unicorns to convince the Princess of the Sun to deliver the filly right to them. It worked, and after restoring Nyx to her full power to once again reign as Nightmare Moon, they whisked her away to the Fortress of the Night. Built by diamond dogs and paid for by the cult, Nightmare Moon rose it out of the ground after she defeated both Princesses as a symbol of her triumph.

But night would not, in fact, reign eternal. The love and friendships Nightmare Moon had made while as the filly known as Nyx had tainted her old, bitter hatred with the knowledge of being love and accepted. This taint, as well as seeing what her reign was doing to those she cared about most, drove Nightmare Moon to do the unthinkable: raise the sun and return Equestria to its natural cycle of day and night. Even more of a shock came when, during a heated argument with Spell Nexus, Nightmare Moon discovered he and the rest of the Children of Nightmare were being controlled by scraps of her previous self, collected and studied by Spell Nexus after her defeat at the hooves of Twilight Sparkle and the other bearers. She defeated the scrap when it tried to take her over as well and systematically removed all the infectious things from every member of the cult.

Even with this done, Equestria was still not truly returned to normal. Nightmare Moon still refused to release the Princesses, for fear that they may in tern banish her once again. Any further discussion on the matter was halted when a large pack of star beasts and other large carnivores descended onto Ponyville, having realized the normal protectors of the realm were no longer around to stop them. Her one-time home in danger, Nightmare Moon raced to the rescue of her friends and loved ones, fighting off monster after monster, taking more and more grievous wounds with each fight. Finally, the beasts were beaten back, but Nightmare Moon was seriously injured, almost to the point of death. Under her adopted mother's pleas, she finally released the Princesses.

To the surprise of everypony, not the least being Nightmare Moon herself, the Princesses were exceedingly lenient with her, though a sentence still had to be carried out for her crimes. Her punishment for her actions was to be stripped of her magic, most of it being Princess Luna's to begin with, and to be looked after and taught the magic of friendship by Twilight Sparkle.

So it would seem the story of Nyx and her past sins would be over. However, this is not the case. Unbeknownst to everypony and forgotten by the cultists, a secret project under development in the depths of the castle was left sealed up until after Nightmare Moon's reign was secured. This project, had it come to fruition at the original predicted time, would have been a defining factor in Nightmare Moon's rule.

This is the story of what happened after Nightmare Moon gave up the throne and returned to being the filly Nyx.

This is the story of the only member of the forgotten Nightmare Guard.

"This sucks," a unicorn worker pony complained to his partner, a large earth pony, as they continued renovations in their assigned area of the castle. "Why are we the only two working down here in this creepy place?"

"Maybe because everypony's tired of hearing your whining whenever you do anything," his coworker snapped back at him. "And if you want to keep it up, I'll show you how good of a dentist I am!" He hefted the jack-hammer he was working with threateningly.

The unicorn backed off. "Alright, alright, I'll shut up! Look, here I am working quietly!" He picked up his tools and began working on his section of the nearby wall. "I just want to know why we're the only ones working down in the freaking dungeon."

To be fair, the two were actually working in the barracks of the castle, though they were connected directly to the dungeon. The two were down there not only because the first had a knack for complaining that his bosses wanted to beat him silly for, but because Night Stone Castle was going through renovation to make it the new Palace of the Moon. The remodeled fortress would be the new home of Princess Luna as she truly fulfilled her role as Diarch of Equestria and ruled as an equal to her sister.

Part of that, she insisted, was not having both sisters rule out of what was known to the masses as Celestia's palace. Yes, it was the seat of government for over a thousand years, but it was built after Luna had become Nightmare Moon and wreaked most of their old home, now located deep in the Everfree Forest. No matter what she did, Luna would never be able to overcome the thousand year image, so she decided to leave and rule from another location.

Lucky for her, her former alter-ego had made a perfect place right outside Ponyville. It needed some remodeling first, to try and remove at least some of the stigma of its previous owner, but otherwise it was perfect.

Thus was why the two luckless workers were down in the barracks, trying to make it more suited for normal guards and not fanatical storm troopers.

"This. REALLY. SUCKS!" the unicorn worker yelled after a time, forgetting that his coworker was just as happy as he was right then.

"THAT DOES IT!" the earth pony roared, wheeling on the first. "I've had it with your moaning and whining and complaining! Here's something to really bitch about!" With a grunt, he swung his jackhammer at the other.

The unicorn ducked, the blade of the hammer coming close enough for him to feel a slight breeze in his mane as it flew past him and embedded itself in the wall he'd been working on. Clutching his tool harder to keep from dropping it, the earth pony accidently turned it back on and began drilling through the wall instead. It only took the jackhammer a second or two to go through the surprisingly thin masonry.

"Turn it off, turn it off!" the unicorn screamed, images of being fired for destroying a palace wall flashing in his mind. With a grunt, the earth pony pulled the jackhammer away, once again nearly hitting his coworker, although this time on accident. Shutting it down, they both looked at the hole gaping back at them. "Oh, damn! We're so screwed!"

"Hold on a sec," the earth pony said, examining the hole. "According to the layouts of this place the princess gave us all, there shouldn't be anything beyond this wall except either solid earth or that cavern it was in until Nightmare Moon brought it up to the surface."

"So, we should head back upstairs and tell her about this, right?"

"Well hold on a second. If this is a sealed up room, probably done so even before Nightmare Moon came to power, then it might not have anything in it. If it doesn't, then there's no need to go running back upstairs with our tails between our legs."

"And if there is something in it?"

"Then we had every right to go running back upstairs and telling her highness everything," the earth pony said with a shrug. Pushing against the wall, he slowly knocked a few more bricks over, gradually making a hole big enough for himself to move through.

"See anything?" the unicorn asked as the other stuck his head in.

"Yeah, a lot of black. Wait... there's something glowin' over there. Watch this opening; I'm going in."

"Whadda mean you're going in!?"

The earth pony picked up a flashlight. "We need to see what's in there. Like I said; if there's nothing, no worries. If there is something, which I doubt, then you can go ahead and get upstairs and tell'm. It's probably just some glowin' moss or somethin'." He brushed past his coworker and into the hole.

The first thing his flashlight caught in its beam of light was a work station at about what he guessed was the center of the room. It was cover with parchment, books, small tools, and test-tube holders filled with test-tubes. Shining the light on a set, he could see this particular group was filled with some kind of black liquid that gave him the heebie-jeebies. Turning away, he looked down at one of the books and read its title: Hybridization: The Science and Excepted Theories. All the other books on the table were titled along similar lines; other sets of test-tubes had various colored liquids in them.

Moving away from the work station, his light found what appeared to be a sort of... pod. It was long, oval, and had a transparent front. Taking a cautious look inside, he was relieved to find it empty. The only thing inside the pod was a cushioned backing, wires, and tubes. Taking a look at its sides, he found a monitoring system with all its readings blacked out.

"You find anything?" his partner called from the hole.

"Yeah; a work station with some weird stuff and some kind of pod thing."

"Seriously!?"

"Yeah. Nothin's in it; I think they abandoned this room a while ago."

"Frigging cult whackos..." he heard the unicorn say. Silently agreeing with him, the earth pony began moving towards the soft blue glow he'd seen earlier. As he did so, he found he was moving along a series of empty pods arranged in a large circle. A quick glance up showed that they were arranged around a large central pillar.

When he got around to the source of the light, he stopped dead in his tracks and swore loudly.

"What is it!?" the unicorn shouted back.

"There's a pony in one of these pods!" The earth pony looked up at the glowing pod's monitoring system and saw it on. "And they're still alive!"

"That's it; I'm heading up!"

As the sound of the unicorn running to find somepony faded, the earth pony moved up next to the pod. The soft blue glow was coming from a bank of lights lining the inside of the pod. The monitor beeped and booped as it said heart rate and blood pressure were normal.

The pony it housed was large; about as big as Princess Luna had been before the second uprising of Nightmare Moon. The mare (she sure looked like one) looked a lot like the evil despot, too. Jet black coat, blue mane, a horn, wings... wait. He looked again. Yes, she had a horn and wings alright, although these wings were large and leathery. Looking down, he found she had a long tail coiled around her back legs. A tail that ended in a sort of blade. He gulped and looked back up toward her face. He felt himself gulp again as he noticed a set of fangs sticking out of her upper lip. "Sure as Tartarus wouldn't want to run into you in a dark alley," he muttered.

That's when the eye closest to him snapped open.

The earth pony yelped and jumped a half a pony length back, his flashlight fixed on the open eye. For a full minute the two of them stayed like that; the earth pony aiming his beam of light at the mare in the pod and the mare staring blankly back in turn. The earth pony noted that her eyes were also like that of Nightmare Moon's: draconic and blue (it could have been the pod's lights but he was pretty sure they were). When a full three minutes had passed and nothing else had happened, the stallion finally got up the courage to walk over to the side of the pod again. All the way the eye followed his movements, not showing one bit of emotion at his presence or his approach.

It occurred to him as he stood over the pod and looked down into that eye that maybe it couldn't express emotion, or at least how ponies did. That or maybe, since it was probably grown in the pod, it had the body of an adult and the mind of an infant? That thought made him begin to  actually worry for the pony-creature inside the pod instead of worrying about it. "Hey, uh, just hold on in there," he tried, laying a hoof softly on the glass between them. "My coworker in heading upstairs right now to get some help, so don't you worry."

The eye seemed to consider that as it continued to stare up at him.

"Jeez, this will sure be some story to tell my kids some day," he told her conversationally. "I mean, findin' a pony trapped in some kind of pod in a secret room in Princess Luna's castle? Don't exactly here that story every day ya know. Hey, what's the matter?"

At the mention of Princess Luna, the eye had widened as if in shock, then narrowed very menacingly.

"H-Hey, come on! You've been good up to this point! Let's just stay calm until the others get here!"

The mare didn't listen. In the blink of an eye all four of her hooves slammed against the inside of the glass wall, cracking it in several places and making the stallion jump back again with a shout. Water, or whatever the liquid she had been laying/floating in was, began seeping out of both the cracks and from the broken seam between the pods main body and its glass cover. Before he could make up his mind on whether to start running or continue to try and calm her down, she kicked the glass again. This time it flew off and away from the pod, crashing against something on the far wall and causing the remaining pod-liquid to surge out.

The stallion's mind was screaming at his unresponsive hoofs to bolt as he watched the mare pull herself out of the pod, her front hooves coming to rest on the bottom lip of where the pod body and glass cover had met. Balancing her back hooves on the ribbed backing of the pod, she opened her large, leathery wings and flapped them a few times.

'Okay, no need to panic yet,' the earth pony thought as he watched this. 'She might have just wanted to get out of there. There's no reason to think she's dangerous just yet.'

Her long tail whipped out behind her, sending the blade on the end first one way, then the other, smashing it into the monitoring system and shorting it out with a shower of sparks and causing the lights in the pod to flicker. She roared as her tail hit, exposing all of her razor-sharp teeth. When she was done, both blue draconic eyes came to rest on him. There was nothing empty or innocent about those eyes now.

'Buck this noise!'

His brain finally got a hold of his legs, and he flew back towards the hole in the wall. He was so fixated on the light from the hole and its perceived safety that he didn't hear the wing-beats behind him until something nailed him in the back of the head. He went sprawling across the stone floor, coming to a stop against what felt like two warm, fur-covered stone rods. Looking up, he nearly wet himself as he once again came eye-to-eye with the mare. She growled at him, exposing her teeth again and bringing her wings up threateningly.

"Celestia help me!" he moaned.

There was a flash of white fangs.

Princess Luna looked around the recently discovered room with a mixture of curiosity and dread. The Children of Nightmare had never given her reason to think they were technologically inclined, preferring to use magic to achieve their goals. They were proving her very wrong at the moment. The room was full of the most advanced technology Equestria had, rivaling the laboratories at her sister's advanced school. In retrospect, that shouldn't have been very surprising seeing as the head of that school, Spell Nexus, had been the group's leader. If they had required all this machinery, he would have been the one to get it for them.

Of course whatever they had been working on had been for her evil half to use against Equestria, but what they were working on exactly was a complete mystery to her. The best lead they had was what the unicorn worker was ranting about when he had burst into the throne room to tell them all he and is coworker had found a secret room next to the barracks and that there was a mare inside. After they had all gotten him to calm down he had given a few more details, such as how there were some kind of pods that the mare was in and that there were a bunch of them.

Luna had immediately organized her guard and made their way down to the barracks. When they had arrived they had found the earth pony worker laying broken and beaten, but thankfully not dead, in the middle of the room's floor. The medics who had later arrived said he had several serious injuries, including two broken legs, several broken ribs, a busted jaw, and internal bleeding. They were sure he was going to make it, but it was going to be a long, hard road to recovery.

What worried her even more was that there was only one way to and from the barracks and they had passed nothing on the way down, nor had any guards noted anything coming up from them. That meant that either it was still loose in the castle, or worse.

"Your highness," Captain Night Skimmer and First Lieutenant Star Chaser landed next to her and bowed.

"Did you find anything?" Luna asked the two highest ranked members of her guard. The two thestrals (bat ponies) shook their heads sadly.

"Unfortunately not, your highness," Captain Skimmer reported. "No open windows or doors."

"No broken ones either," Lieutenant Chaser added. "At this point we can only assume it escaped the castle, but how it did so without alerting any of the guard is beyond us."

Luna mulled that over in her head as well. Getting out of the castle without breaking a window or door and not alerting any of her guard should have been impossible.  As she thought, she looked back over the pods surrounding the central pylon. They were vaguely reminiscent of the life support tubes she'd seen in one of the labs in Celestia's school. And hadn't they found several books on the work station about genetics and hybridization?

A cold feeling began settling in the pit of her stomach.

And hadn't the Children of Nightmare's goal been to resurrect Nightmare Moon with scraps of what she had left behind? Could their backup for failing magically been to try with technology? The unicorn had said there was a mare in the broken pod...

"I agree," Luna told them. "The creature is no longer in the castle. Captain Skimmer, you will take troops to quietly search nearby Ponyville. If you find nothing, post guards near the homes of each of the bearers; at least four to each. The home of Princess Twilight Sparkle should have at least eight."

"Yes ma'am!" With a salute he was off.

"First Lieutenant Chaser, you will take the remaining guard and perform a quick survey of the acres of the Everfree Forest nearest both this castle and the one my sister abandoned after my... incident. If nothing is found, return as quickly as you can; we will need as many hooves at the ready as possible."

Saluting, she was also off on her assignment.

Once the lieutenant was gone, the princess turned to her secretary. "Miss Breeze, please send forth a letter to Headmaster Spell Nexus informing him that there has been an incident here involving a project undergone by the cult and that we need his knowledge of it to ascertain how to proceed. Please relay to him the urgency in which he must arrive."

The blue pegasus bowed. "It will be done with all possible haste, your highness."

Once she was gone as well, the Diarch of the Moon slumped slightly were she sat. "Yet another case of headache and sorrow caused by my brief loss of sanity. I pray that someday this will all finally end."