Darkest of Nights

Celestia was speechless as she neared the castle she and her sister had occupied before moving to Canterlot. When the two sisters had left Discord's old castle they had intended to never return to the foreboding structure deep in the forest, but what lay before Celestia's eyes was anything but deserted.

Where tangles of brush and vines once stood was now small houses and stores, the tree canopies blocking out almost all of the fading sunlight. However, there was enough light for Celestia to see that the small town was actually populated by ponies, the inhabitants coming out to see who their visitor was.

... at least, Celestia thought they were ponies. Unsure if what she was seeing was a trick of the dim light or her imagination, Celestia stopped in her tracks as her eyes focused to the darkness. She let out a gasp as she confirmed that her eyes were not playing tricks on her; what she was seeing was real.

The creatures coming approaching her looked like the average pony, except for one strange feature; their wings. Instead of having the familiar feathery wings that all pegasi had, these ponies all had leathery bat-like wings. Celestia knew that nopony had wings like these naturally, and that somepony who knew extremely advanced magic was responsible for this abomination. There were only three ponies that Celestia knew who could transform a pony like this; herself, Starswirl the Bearded, and...

"Luna. Where is she?" Celestia asked one of the bat-winged ponies who had approached her.

The bat-winged pony looked confused for a second but then spoke. "You mean Empress Luna. Yes, follow me." the pony said, nodding toward the castle Discord once occupied. As Celestia was led through the small town she saw that every single pony there had the strange bat wings on them, and not one normal pegasus, unicorn, or even earth pony was to be seen. However, her biggest shock came as she approached the ornate stone bridge leading up to the castle. Two guards stood on either side of the bridge, and as Celestia approached them she recognized them as some of the royal guards who had gone missing. The armor they wore looked as if somepony had modified it and had dyed the metal dark blue. The guards saluted Celestia as she walked by, but all the princess could do was sigh in depression as all the clues before her came crashing together into one indisputable answer.

"Sister... what have you done?" Celestia whispered to herself.

Celestia stood in the old throne room, waiting for one of the guards to inform the 'Empress' that she had a visitor. Looking around the area, Celestia saw that while Luna had kept the twin thrones and regal banners of the sun and moon, the younger alicorn had changed the rest of the decorations in the castle. The new decor was now to Luna's tastes and portrayed the glamour and wonders of the night, midnight blue and silver banners dominating the halls and rooms. Celestia would have been genuinly impressed by all the work that Luna had done in such a short amount of time if it weren't for that fact that she had gone against Celestia's orders, not to mention that she was responsible for the missing ponies across Equestria.

The Princess of the Sun's thoughts were interrupted by the sounding of a trumpet. Turning to face where the noise came from, one of the side doors opened and Luna entered the throne room while flanked by two members of the Blackguard. Though she didn't show it, Luna was obviously quite nervous about having her sister here; Celestia had figured out everything quicker than she had expected. However, she was able to maintain her composure and hoped that her elder sister would be impressed by what she had accomplished. "Welcome, dear sister. to my new kingdom." Luna said in greeting, opening her wings to embrace Celestia.

Celestia didn't return the gesture, instead concentrating as hard as she could to refrain from exploding with anger and betrayal. "Luna, what is all of this? After I had told you that we need to stay united, not to mention you've fillynapped Tartarus knows how many ponies!"

Luna's smile quickly fell away as she defended her actions. "I have no intention on isolating my kingdom from you! Do you not see your throne still in place beside mine? All I did was create a kingdom that can thrive and prosper under my moon as your kingdom does under your sun. And everypony here came willingly, not under any force! All I did was seek out the ponies who appreciated my hard work and wished to join me in my new kingdom."

Celestia was in shock but managed to contain her growing fury. "That still doesn't excuse whisking away so many ponies without at least allowing them to inform their loved ones." Celestia said. "The best course of action now is to allow everypony to return home and we can discuss this whole matter later once we have settled other matters."

"No!" Luna spat out, surprising Celestia. The room seemed to darken and a dense fog began to billow out from Luna's hooves, quickly covering the floor. Luna's coat and mane began to darken once again, and Celestia took a cautious step back as she felt her sister's level of power begin to rise at an alarming rate.

"Luna, what is going on? How are you... wait, something feels... familiar..." Celestia trailed off. The aura that Luna was emitting was clearly not her own, but it did remind Celestia of somepony. It didn't take long for Celestia to recognize it, and with her eyes widening in horror she adopted a defensive stance and quickly cast a protective shield spell around herself. "Luna, stop this! It's Sombra, he's corrupted you somehow!" she cried out.

Celestia's younger sister grinned and laughed. "He hasn't corrupted me, sister. No, he awakened my true power and showed me the truth, that you want to keep me in your shadow while you selfishly keep everypony's love and admiration for yourself!" Luna shouted.

"That is enough!" Celestia said in anger. She tried approaching Luna but the two Blackguard ponies quickly intercepted the sun princess.

Four more of the elite unicorns dressed in black burst into the throne room and surrounded Celestia, their horns glowing as they prepared to defend their leader. Luna let out a chuckle. "See, sister? They know who their loyalty lies with, as does every pony under my rule. Not everypony under your rule believes your lies, and those who chose me were smart enough to see the truth."

"Luna, this is ridiculous! I would never..." Celestia said in defense, but Luna quickly held up a hoof to silence her.

"Enough! We have had enough of thy treachery!" Luna's voice thundered as she adopted the royal voice she used to address the public. "If thou can't accept my offer of peace, then thou shalt have to live as thy enemy! Escort Princess Celestia back to her kingdom."

The Blackguard unicorns closed in around Celestia as Luna turned to leave, signalling the conversation was over. "Luna, please..." Celestia said, trying once more to reason with her.

Luna turned and snarled at the sun princess. "You shall address me as Empress Luna the next time we meet." she said coldly before leaving the throne room. The ponies surrounding Celestia pushed the