It should be a dark and stormy night.
That's what the dark blue pegasus thought to himself as he stared into the night sky lit by the stars and moon. Perhaps the rain would shield him from his own misery. His heart ached as he gazed at the moon and pictured who was imprisoned upon its surface, his liege lord, the Princess Luna. As he gazed out a single tear slipped down his cheek as he remembered that fateful night, almost a thousand years ago...
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A young knight adorned in the black armor typical of knights in service of the lunar princess stood outside a door, scratching the floor with his hoof with impatience. "Come on your Highness, you'll be late."
"Does it really even matter?" A voice asked from the other side. "Nopony appreciates our nights, would they even notice if the moon never rose again?"
"Of course they would." The Knight said, trying to calm the princess. "They may not say it, but how can anypony not appreciate the beauty of the night sky?" Or your beauty? He thought to himself.
The door cracked open and Luna poked her face out. "You... you really think they appreciate our nights?"
The pegasus knight took the princess's hoof in his own and led her into the hallway. "Of course they do. It's the whole reason as a squire I strived for the Lunar Knights, Everypony would starve without the harvest moon to direct the farmers, even the tides would vanish without you."
Luna gave a small smile that made the Knight's heart soar, but he was quick to keep his emotions in check. He had a duty, and that came before all else.
The Knight followed her down the hall wearing the traditional knight armor. From his extensive training he had become the head knight, and the Princess's personal bodyguard. As such he was allowed to choose his own weapon. Strapped to his back were two swords, the first within easy reach to wield in his mouth, the second blade had hooks on the pommel that that fit into the cross shaped band that secured his tail in place. With a single motion he could draw both blades and attack from two different angles. Each blade was also imbued with a special property. He had no use for the abilities, but each blade was a gift from the two princesses, so he didn't object.
His coat was a dark blue, almost as dark as the Princess herself. His mane was gray and spiked on top, while going down his neck slightly more than most stallions. His platinum eyes shone with passion and matched the color of the shield cutie mark on his flank. It had always been his talent to protect others, and he got to use this talent to protect the most important ponies in all of Equestria.
As they neared their destination the Knight had to remind himself of what tonight was, the Winter Moon Celebration and the longest night of the year. The princess would go out and in a ritual more for show than anything else, raise the moon. As they neared the double doors that led to the courtyard Luna's excitement built until she was grinning from ear to ear.
As the doors opened Luna's smile quickly vanished as she saw they empty courtyard. Only Princess Celestia and her personal guard were there.
"W...W... We don't understand, Tia, what's going on?" Luna asked her sister.
"Luna, I'm sorry." Celestia said, voice thick with pity for her younger sister. "I cannot control the turnout for public events. But the moon still has to rise."
The Knight watched Luna quietly sob. After a moment she opened her eyes, which were full of tears. "All we want is for ponies to appreciate the night! Is that so much to ask? We suppose so, if everypony simply sleeps through it! Too tired to even celebrate a holiday!"
"Princess please," The solar knight said. "This is unbecoming of a princess. You must maintain a respectable image." The young knight wanted to beat his white counterpart for giving no mind to the princess's emotions, but stayed himself.
"Keep a respectable image? To who?" Luna cried. "There's NOPONY HERE!"
"Sister please, let's just get this over with and put it behind us. There will always be next year." Celestia said.
"... Fine." Luna replied. Her horn glowed and on the horizon the full moon rose slowly rose. When it was up the Princess turned and left without a word, leaving her knight to keep up and leaving her sister outside.
When Luna returned to her chambers she walked in and slammed the doors shut behind her. The young Knight stood outside the room, keeping an ever vigilant guard. And though his heart ached to see her in such pain, it was not his place to comfort her.
As the hours passed the crying wound down until the only sounds from inside the room were the princess muttering to herself. Eventually she called out to her knight.
The Knight opened the door. "Yes, your Majesty?"
"Come inside, We have need of your assistance."
As the Knight ventured inside he was greeted with the scent of the princess. Quickly pressing his personal thoughts to the back of his mind he walked up and bowed until the Princess motioned for him to stand. As he did he thought he saw her eyes glowing, but put it aside as paranoia. "What do you need my assistance with Princess?"
"We need to know how loyal you are to us."
"Your highness! I would never betray you!" The knight exclaimed, somewhat surprised she would even suggest otherwise.
"Would you follow our orders without question?" She asked.
"Yes, of course!"
"Would you kill if we asked you too?"
"... Yes, your highness."
"And would you do as we command, even if our sister orders you not to?"
"... Yes."
The princess smiled. "That's good. It pleases us to know that somepony appreciates us." Then right before his eyes, the princess began to change.
He now knew he wasn't imagining things as Lunas eyes glowed teal, the pupils becoming dragonlike slits. Her coat darkened to black as she grew taller and more slender, quickly reaching the stature of her older sister. Light began to gather around her body and coalesced into metallic blue armor that covered her chest, hooves and head. Lastly her mane and tail lost their solidity as they became flowing clouds of stardust, much like her sister.
"You-your Highness?" The Knight stuttered, completely shocked by the transformation.
"Just a cosmetic change." The princess said with a deeper, almost seductive voice "No longer will I suffer in my sister's shadow." Then she turned her piercing gaze to the Knight. "Will you still follow me?"
"Yes, of course!"
"Then do so." She said as she left the room.
They walked together to the room of Princess Celestia. To the Knight the Princess seemed even more beautiful than before, but he refused to allow that to interfere with his duties.
Soon they came to Celestia's chambers, the Solar Knight at the door immediately jumped to attention. "Halt! Who goes there?"
The Lunar Knight looked at the Princess, who nodded. In a second he reached behind him and drew his blade with his mouth as he ran towards the other knight. The white pony also drew his blade and blocked the blow, but the lunar knight pushed their blades to the ground and flicked his tail, the hooks of his tail band catching the second sword on and drawing it. The second blade swung through the air and with a dull squelch embedded itself in the pony's neck.
As the guard fell to the ground without a sound the young knight flicked his tail again, the blood being thrown from the blade. With a second motion the blade swung through the air and flew back into the sheath.
Having acted on well-honed battle reflex, the Knight's mind caught up with his actions and he stared at the corpse of the Solar Knight. He hadn't been friends with him, but both being head knights, they saw each other enough that he mourned his death, but he had sworn to do whatever was asked of him, so if there was any guilt, he suppressed it.
The princess then walked over the body and opened the doors and revealing Celestia, who was in the center of the room, her horn glowing with powerful alicorn magic.
"Who are you?" She demanded. "What do you want with me?"
"Don't you recognize me?" The Princess said, turning on the spot. Celestia said nothing until she caught sight of the cutie mark.
The glowing of her horn stopped as her firm expression was replaced by one of shock "L-Luna? What have you done to yourself?"
"I'm sick of this." The Princess said "Always being ignored, being second best! You have no idea what it's like, to watch your own sister be revered while nopony even knows your name! Do you have any idea how many nights I cried myself to sleep?"
"Sister please" Celestia pleaded "Settle down and let us talk about this."
"No." The Princess said. "The time for talking has long passed. And don't call me your sister! If you were truly my sister, you would have been there for me instead of basking in the spotlight!" Celestia opened her mouth to speak, but was interrupted. "No, I have no sister. And my name from now on shall be Nightmare Moon! Ha Ha Ha! Appreciate yesterday's sunlight, for it will be the last time you ever see it again!" Nightmare Moons body then turned to mist and cloaked the young knight. When he could again see, they were no longer in the castle. Instead they were atop a mountain that overlooked the forest and castle.
As Nightmare Moon turned away the young knight said "Is it true? Will the sun never rise again?"
"Is that a problem?" Nightmare Moon asked.
"Of course not your Highness. I already told you, I chose to become a Lunar Knight over a Solar Knight. I serve you."
"That is good to hear." She said. "Now follow me. I wish to see how my subjects react to the night now that they have no choice but to see it." Then she spread her wings and took to the sky, her faithful retainer following behind her.
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It wasn't fair
That's what Nightshade thought to himself. All the Princess wanted was attention, to be loved. Did that warrant what was now almost 1000 imprisonment? He didn't think so. Nightshade once again looked at the moon and said in a voice made gravelly by time "I will see this wrong made right my Princess. I swear it."
Reaching up he removed his black helm, his symbol as a Lunar Knight and token of loyalty to the royal family. Sneering at the thought of Celestia, he cast the helm aside and looked at Canterlot one last time before opening his wings and taking to the sky.