Long ago Luna had a student. She taught him many magics of the night. The dark magic that were shunned by her sister but still Luna taught him. For many years she trained in secret showing him the magic he would keep it. Necromancy and darkness magic this was the pony's specialty, and sombra was his name. Power was his game.
One dark and beautiful night in the courtyard, sombra and Luna were training.
They smiled at each other warmly as sombra completed the spell he was given he chuckled "Luna why so tense tonight?" He asked teasingly to which she replied with a sigh "we wish our sister knew how beautiful the night really is how much this magic could do...sorry we have alot on our mind right now sombra" she said looking to the stars. Sombra sat down on a patch of grass and looked to the moon "it is beautiful as always Luna, celestia should know that..." He smiled at the moon thinking of what he could do to use this spell in his dominating efforts he kept secret from Luna.
Luna felt as if celestia had casted a spell over the whole of equestria so the night was shunned. She looked to sombra and gave a sly smile thinking of what she could do to fix that she looked away and up at the moon "The magic I posses might be able to take her down and sombra with me we will deginatly be able to take her on...no...what am I thinking! I can't fight my own sister...but maybe" a almost inky black spread from her eyes but it quickly receded and then she continued with the lesson "sombra what do you intend to do with these lessons we are finishing this night for you to travel yes?" she smiled warmly. To which sombra almost froze then he decided to just tell her the truth "I'm going to dominate this world Luna ill show everypony in equestria the power of the darkness." He smiled. Luna disbeleived it and chuckled "Always messing with us aren't you sombra?" he laughed nervously. Of course she would never understand, she always thought he was good "just do me a favor and drop the royal we for once? My training is complete today" he said smiling. Luna nodded simply "but of course, tonight is the night sombra, tonight is the night I will tell you goodbye so you can travel" she smiled at him. He chuckled and bowed "so I can learn more magic my princess." He said he wished that luna would learn the truth of the night instead of bowing to her sister.
Luna stood next to sombra looking at the moon "beautiful is it not?" Then she looked at sombra feeling dizzy "S-sombra....lesson is over you may leave" she said acting like there was nothing wrong with her. She then trotted to her chambers and looked in the mirror, for a moment, she didn't see her face but that of a monster...one that sent shivers down her spine. it was a back silhouette of herself. It grinned wickedly at her, she played it off as not sleeping well enough and went to sleep again.
She dreamed of a night where all ponies could relish in sun and moon, it was peaceful. She stood by her sister smiling. While in real life the sun rose over equestria, as celestia looked over canterlot.
Many years ago before the elements of harmony were discovered in equestria. There were two sisters one of the night and one of the day. The kept glance in equestria, until something changed that balance. The scale was tipped into the favor of the night and the first solar eclipse was created.
Luna was in her royal chambers sleeping during the day as such she did not notice the blackened sun that threw equestria into terror. However something else lurked in her chambers as a thick black fog rose and a mysterious black alicorn, without any features no cutie mark, and no face,approached the sleeping princess. The mysterious alicorn made a chuckle and opened its mouth to show eerie white teeth that seemed to glow against the black "so princess of the night I shall give you its true power...and I shall let you have it unnoticed until it strikes and creates how you should be..." The fog rolled over the sleeping princess and surrounded her entering her with every breath she took. The mysterious pony smiled wider then turned and it disipated into the rest of the black fog, and the sun shone once more. No trace of the fog or the alicorn.