She hadn’t been that much younger than she was right now when she had ventured into that cave. She remembered that fateful day more than she ever wanted to. Nightmares of it still plagued her. But it wasn’t what she encountered that had scared her so. It was what she had done for her own safety. Something Celestia never would have, and something she doubted she would have the ability to do…right now anyway.
Celestia had been off gathering supplies for the night. They had been setting up camp next to what seemed like a small cave. Bored and with nothing to do until her sister returned, the Alicorn decided to foray into the cave. It seemed fine at first. The cave was dimly lit so she could vaguely see where she was going. It became apparent to her that the cave descended for some way, though she chose to carry on exploring. As she jumped and climbed over a set of rocks, a distinct rumbling hit her ears. That should have been Luna’s first warning that something not friendly was lurking in the bowels of the stone walls. She chose to ignore the warning and continued exploring.
After what felt like some time, she figured Celestia must have returned by this point. What little lighting the cave had was also fading. That should have been her second warning, yet she chose to ignore those facts too. After casting a small spell, enough to light a small way in front of her, the young filly continued forwards. She reached a ledge which seemed to drop down into the bottom of the cave. Before moving a hoof off the ledge, she heard snoring for the first time. That should have been her final warning. Instead, curiosity filled Luna to the brim. She spread her wings and slowly flew down to the bottom of the cavern. The light from her spell revealed what awaited her. It was a very large, blue dragon. It was snoring heavily and guarding a huge mountain of gems and several other precious looking metals.
Luna stared in shock at what she had found. She had been told a little about dragons by her parents. It had been one single, stern warning. Never, no matter what, ever wake a sleeping dragon or even think about touching its hoard of gems. The warning echoed in Luna’s head. She had no intention of disobeying it. She slowly took a few paces backwards so she had enough distance between her and the great beast in order to take flight and make it out of the cave as quickly as possible. There was no doubt in her mind she would receive a stern scolding from Celestia once she returned.
Her wings unfurled and she gently glided up to the ledge she had flown down from. However, she misjudged her footing. The girl slipped and went tumbling down into the pit, hitting the bottom with a loud thud. Luna groaned in pain as she checked herself for injuries. She had managed to not injure either of her wings, which was a good sign. Slowly she lifted herself onto her hooves and sighed quietly. She turned around to try again, only this time she was greeted by two large yellow eyes glaring at her.
“Pray tell…” came a quiet, but powerful voice, “what is a puny pony doing in my cave?”
Luna was frozen. She couldn’t even open her mouth, much less talk.
“Hmph” the dragon said with contempt, snorting smoke over the filly.
“Here to steal my gems perhaps?” he asked, eyeing her carefully.
Luna once again said nothing, though not for lack of trying.
“Mute are we, pathetic little pony? Then I shall interpret your silence as an admission of guilt. You shall now find out what we dragons do to those who lack the brains to stay away from our hoards.”
The dragon raised its body slightly, but it was more than enough to gain ten feet above Luna. It snorted once more, covering her in more soot. She could only stare in horror and await her grim fate. The dragon took a deep breath in and in an instant, exhaled.
The world seemed to slow infinitely into darkness. Luna was surrounded by a nothingness she had never felt before. The anger of the dragon, the inevitable disappointment of Celestia…they all seemed miles away, another lifetime away. Where was she? Did it even matter? That darkness around her, it felt consuming. It felt as though it had jaws and was coming to eat her alive. What on Equestria was happening?!
Then, out of the seemingly infinite darkness came an infinitesimal ray of strength.
“I shall not be bested” came a voice, but it didn’t belong to Luna, even though it spoke with her voice.
“I shan’t?” Luna asked, finally being able to speak once more.
“No you foal, you shan’t!” came the deafening reply.
Luna sighed. It felt like the sigh lasted a lifetime.
“Get a hold of yourself Luna. Now you’re hearing things…” she whispered.
“FOAL!” came a booming voice. It was her own, but stronger…darker…crueller…
“Who’s there?” Luna asked timidly.
“Who are you?” came the reply.
“I…I’m Luna. Sister of Celestia, and daughter of-“
“NO!” roared the voice, “Celestia is YOUR sister, you are not hers! Do you wish to live in her shadow your whole life?!” it demanded.
“What do you mean?” Luna asked, a little scared.
“I have seen your future, Luna. As I have seen hers. Take control of your strength. Show Equestria the power of the night goddess!”
“Goddess? No…I’m just…Luna…” Luna said, getting more and more frightened by the moment.
“No, you are the Moon! The embodiment of cold, hard strength!”
Luna said nothing for the longest time.
“I was named for the moon. I mean, I was born at night.”
“You still don’t understand, do you? I am the embodiment of that cold power you possess. The raw strength you have yet to tap. I am the Nightmare to the Sun’s dreams. I am the fury and the power you so desperately need. Now, little Luna, allow me to prove to you that power!”
There was silence for a split second, then a blinding flash of light. Luna saw herself, she saw the Dragon as it was breathing its flames down upon her. But she was not in control. Something else was controlling her, showing her something, something she knew she didn’t want to see, yet she couldn’t look away.
Time readjusted itself as the dragon loosed its flames onto Luna. But they had no effect on the shield she had produced. A dark, thick bubble that caused the flames to evaporate into nothingness, as if someone had flung the weakest of spells at her. The dragon recoiled in shock.
“How?” he demanded.
Luna only smirked.
“Little dragon. Oh little dragon. If only you had any idea whom you were dealing with. Sadly you will never live to see the night reign supreme.”
“What are you little pony?” the dragon asked angrily.
“I am Luna, the nightmare of the moon!”
With that, Luna’s horn glowed a foul purple and lashes of lightning streaked out of it, slashing and slamming violently into the dragon, causing gashes and tears in its skin. The dragon roared with pain.
“impossible!” it roared in horror.
Luna leapt a few feet backwards, the smirk on her face only growing. She turned her head to something that it seemed only she could see. In the infinite space, the ‘real’ Luna could only stare in horror at the events that were unfolding before her eyes.
“How can you have such power?” the dragon asked, glaring furiously at her.
“You poor foal. You’ll never understand what you’re facing. Though I suppose in a way, I should be thanking you.”
“What are you-“
The dragon was cut off as more bolts of thunder lashed through his scales, tearing them clean off and scarring and tearing at the vulnerable skin below. The dragon stumbled backwards and slammed hard into the stone wall, breathing heavily from the beating he had taken.
“You must be wondering by now, how is it I have the power to tear off a dragon’s scales? It’s simple really. I told you, I am simply demonstrating the raw power you have at your disposal as an Alicorn. You want to know the best part little Luna? This isn’t even your most powerful.”
The real Luna let of a gasp, pleading for this being to stop hurting the dragon. She simply smirked as her horn glowed once more, charging a bolt of incredible power. In the next instant came a horrific roar of pain and anguish as the bolt pierced the heart of the dragon, killing it instantly. Its body collapsed to the ground with an almighty crash, blasting the gems all over the pit.
Luna stared at the dragon’s body, satisfied with her work. She turned around and smirked at the ghostly Luna.
“Now you know. Now you have released me. I will only grow stronger, Luna. Soon we shall become one, truly. On that day, none shall stand in our way. Not even Celestia!”
Luna let out a gasp of horror, then everything went dark and she felt a painful sensation around her body, as if something was forcing her back into reality.
Several moments of unconsciousness later or perhaps several days…she couldn’t be sure, Luna opened her eyes to only darkness. She felt a horrible pain on her head where she must have bumped it.
“Uhn…what happened?” she asked herself, though no one was around.
She cast a weak light spell with her horn. She was at the bottom of a cold, dank pit that was completely empty. Was all she had seen just a dream then? She must have fallen off that ledge and smacked her head pretty hard…She could only hope all she had seen was nothing more than a terrible dream her mind had concocted for whatever, horrific reason. She struggled to her hooves and stood for a moment, maintaining her balance. She spread her wings and took flight, soaring out of the cave. She knew when she returned she would receive the scolding of a lifetime from Celestia. However, even as she was flying out, she couldn’t shake the strange sensation of a pair of eyes watching her from the shadows…