You may be familiar with the story of King Sombra and the Crystal Empire by now. What you may not know, is the truth.
Celestia, consulting the help of her sister Luna, and the Elements of Harmony, were able to swiftly and easily defeat Sombra.
This, is unfortunately not the truth.
You see, Celestia and Luna fought their way through the guards and militants of the Crystal Empire for five hours, until eventually, they reached Sombra's chamber. The chamber door had only barely cracked open, and a bolt of magic had shot from Celestia's horn, piercing Sombra's chest. He slid backwards several feet, but remained unmoved. Keeping his devilish grin, as the ground in front of where he formerly sat cracked open like dried skin.
His flank finally left the ground, Luna looked shocked immediately recognizing the extremely powerful offensive spell Celestia had just used. And Sombra had just taken it, without even flinching. Luna began to recount the words spoken to her by her sister. "Do not appear to be fearful. Appear to be feared of. If Sombra senses a hint of doubt, he will strike it down where it stands." Luna's eyes widened.
There was no time to react, a bolt left Sombra's horn striking Luna's breast plate. It cracked down the middle, launching in two different directions as Luna flew backwards. Celestia turned her head quickly, mouth agape, then spun around to once more face Sombra. Sombra's grin had become impossibly wide, baring every nashing fang and tooth in his mouth.
Celestia's horn once more came to life with magic, Sombra's aswell, preparing himself for whatever offensive or defensive spell Celestia was going to throw at him. Surprisingly, instead of an attack, Celestia simply lifted both of the straps on either side of the saddle bag on her back. Slowly, yet steadily, six medallions emerged from either pocket of her saddle bag.
Sombra tilted his head back a bit from it's rather pointed frontal stance it was at a moment ago. Sombra opened his mouth to speak, his voice cracked and gurgled as he spoke. "And who is this?" Celestia could only laugh in response. "You don't know what these are?" Silence befell the room. Sombra held still, the purple flame of his eyes steadily blowing in the breeze from the windows nearby. "These are the Elements of Harmony, I thought somepony of your stature would know of these surely." She said proudly.
Sombra remained unmoved by the statement. Suddenly the medallions began to violently spin in a circle, floating around Celestia's neck. Sombra retook his former frontal offensive stance, preparing for whatever Celestia was about to do. The yellow glow of Celestia's horn became only brighter, as the medallions spun so quick they had became a golden hoop simply floating around Celestia's throat. Without warning, the medallions stopped.
A yellow beam quickly shot from every single one of the medallions, firing into one controlled point. A ball of light quickly began to form, and grow. As if to prove a point, Sombra let a noise slither from his throat. It was a laugh at heart, but came as if it were a muffled growl. Celestia calmly closed her eyes, as she knelt her head lower, touching the tip of her horn to the back of the ball of light. As if she had popped a balloon, a large beam shot from the front of the bubble, bathing the room in a blinding sunlight.
Flesh and muscle tore from the bones of Sombra. An ungodly scream echoed throughout as Sombra's mortal coil was completely destroyed. The fight had ended as quickly as it had began. Celestia, determined, would not let two pony's die in that chamber on that day.
She turned quickly to her sister, whom lay limp on the ground, her breast plate only a few feet behind her in two different directions. She ran to her sisters side with such force it knocked her crown from the top of her head. She quickly tried with everything she could to recall what spell Sombra had used on her dear sister. Could it have been...? No, there was no possible way. But there was no reason to take a chance either.
Quickly, and without warning, Celestia delivered a swift punch to Luna's gut. A black liquid rapidly spewed from her mouth and right nostril. Luna arose from the chamber floor, coughing violently, expelling the rest of the black liquid from the back of her throat. Celestia took note of everything about the liquid.
It had taken on an extremely dark shade of black, so much so that the light in the area around the splotches was being consumed by the liquid. It had come from two different orifices. But most important of all, was that the liquid was stationary. It was un-moving, it made no attempts to regroup with the rest of itself, laying only millimeters away.
Celestia looked at her sister, whom wiped the rest of the dripping liquid from her chin. She flicked the over side of her hoof, knocking the liquid away. She quickly glanced behind her sister, to see the partially liquefied muscle tissue in a pool on the ground where Sombra had once stood.
Luna giggled. Soon after another came, and another, until eventually Luna was laughing hysterically. Celestia wore a look of relief, but was crying on the inside. She knew, that the spell Sombra had just used moments before on her dear sister, was an evil, and a powerful one. Like a cancer, it would grow inside of her, until one day it would reach a boiling point.
This boiling point, was Nightmare Moon.
The fire crackled and popped. Four chestnuts, engulfed in a yellowish glow, hovered steadily over the flame. Luna, who sat only inches away from her older sister, began to speak. "Tia'?" There was a pause. Celestia withdrew two of the four chestnuts from the flame, spinning them in a circle in mid air. A simple acknowledgement came from Celestia. "Hmm?" Luna looked to the floor beside of her, she retracted her hoof and began to draw an invisible circle on the floor with the tip. "You'll never leave me... Right?" Another pause. As if the pair were outside, the sounds of the night surrounded them despite being indoors.
Celestia stopped spinning the chestnuts, she moved one in the direction of her sister. A dark purple aura surrounded the treat, and pulled itself closer to Luna. Celestia looked down at her sister, whom stared blankly into the flame. The reflection of the fire in her eyes was slightly disturbing to her big sister. She looked back to the chestnut that sat dancing in mid-air. "Never." The reply was short and simple, but spoken softly at the same time. "I will never ever leave you." Celestia expanded one of her massive wings from herself, folding it over Luna's side and pulling her in close. Luna lay her head against Celestia's neck, taking a bite of the chestnut, as Celestia pulled the remaining two from the flame, and lay them on a plate.
Celestia began to hum a tune Luna was familiar with. Celestia's voice was soft, almost motherly. She began to sing the melody quietly, as Luna's eyes grew heavy. "Come little children, I'll take thee away, into a land of enchantment..." A guard outside peaked his head around the door, smiling at the two sisters. The guard he stood with smacked him back into attention as one of the maids drew closer. Luna had chimed in at this point. With both of their tiring voices in tandem, they sang openly. The dying flame, their audience. "Come little children, the times come to play, here in my garden of shadows..." Their voices echoed on, until they had both been taken by the spell of sleep.
The maid and the two guards had been listening the entire time. The maid entered their room, pulling a blanket from the bed, and over the two. She closed the door leading to the balcony, and blew out the oil lamp on the nightstand. She exited the same way she entered, stopping to have a word with the two guards. "Make sure those two angels rest easy." The one who had formerly peaked his head through the doorway to listen, smiled and nodded. His partner saluted the mare with a smile on his face as well. Pulling the door shut, the mare spoke something in her tongue the guards didn't understand. "Reashvanu." The meaning of the phrase, strength to those whom face the impossible.
Birds were chirping, the earliest of rising ponies were just then creeping from their beds. "Pa-pa, pa-pa! Come, let us watch the sun rise before we begin the day!" A young filly called to her father, who was still attempting to pull himself out of bed. Scratching his chin, and wiping the sleep from his eyes, he trotted over to the window with his daughter. The two looked on, waiting, and waiting for the sun to rise to dawn a new day. But on this day, there would be no sun.
You see, in the night, Luna had cast a spell without her sisters knowledge. She had crept to the highest peak of the towering Canterlot Castle, and had cast a spell on the sun, that made sure that Celestia temporarily could not raise it. When Celestia entered the room, the spell had already been half-way complete. Celestia could not believe what her sister had become. Celestia had underestimated just how much ferocity the evil possessed. Had it not been for her unmistakable mane, Celestia may not have even recognized her sister. Then, Luna turned to face Celestia, and then she knew the full extent of the toll the evil had taken on her.
Celestia thought she was ready for this, but in truth she had been lying to herself ever since it happened.
Their battle ensued, resulting ultimately in Luna's inevitable banishment to the moon, for one thousand years. Celestia proclaimed victory, but at a price. Not only had she lost her sister, but something else had happened as well. You see, Luna had created deciples. Some followed blindly. Others, had to be taken by force. These pony's, Pegasus, Unicorn, and Earth Pony alike, were suggested to a very dark form of magic.
Something that, in Nightmare Moon's rage and hatred, had created.
This magic, ensured that even if Luna were to fail, she would cause her sister some strife. When it did, Celestia questioned just how black her sisters heart had become. Murders, disappearances, pure undefined chaos. Royal hunts took place, in attempts to find those responsible. Said to have inhabited the woodlands of early 5th century Ponyville, they found several of those they were attempting to seek.
Some of them, willingly turned themselves in. Others killed themselves by whatever means they could. Others went into hiding, and continued their atrocities in the name of their princess. Their mother. Princess Luna, mother of the night.