"Your magnificence," a grovelling Thestral began. "I bring a message from the tyrant-Sun," he claimed, bringing out a scroll with one hoof. An old method of conveying messages, but to take the time making such a thing, well. Nightmare Moon's curiosity was piqued.
The dark Alicorn plucked the thing out of her servant's hoof and unfurled it while bringing it closer. She began reading, and every word only made the developing frown deepen. "Truce...? Changelings? She, what? Servant," she commanded. "Was this verified to be a legitimate note from my misbegotten sibling?"
It was, of course. Even upon further questioning, bringing the Thestral's commanding officer in as well, it appeared to be genuine. Soon enough ponies of all kinds were running and fluttering in a form of controlled chaos as at least the chance to meet and speak was accepted, and a scroll of appropriate gravitas written. It was sent with all haste under the flag of truce, and all forces were instructed to stand down within the day. Radios made this, at least, easy enough.
Merely two days later Nightmare Moon, alongside an entourage of elite Thestrals, approached the slopes of Canterlot. The city itself was as pristine as ever, but the plains beneath were littered with the dead and wrecks of war machines. The lines had long been drawn, and scarcely moved in the last year or so. Daybreaker had vacated the city some time ago and retreated into reconquered Las Pegasus, so the former capital was as good a meeting place as any. With a flap of her wings, Nightmare Moon took flight.
She surveyed the lands beneath with contempt as the city approached. She would have to reinforce this region if she ever wanted to take Canterlot. To her surprise, the palace was still manned by both the Solar and Lunar Palace Guards. These fifteen hundred were taking their duty to both Alicorns truly seriously if they were still here despite everything.
Nightmare Moon landed in one of many secluded gardens, immediately approached by a Palace Guard. He bowed before her. "Your majesty, it is an honour to receive you here. Your counterpart arrived only shortly before you," he explained. "If you would follow me, I shall lead you to the meeting place."
He rose and turned upon receiving a nod and made his way into the building, expecting his ruler to follow. Nightmare Moon sneered for a moment, but followed a few heartbeats later. As she'd expected, everything looked very nearly as before. A little dustier perhaps, a bit less vibrant, but unchanged otherwise. Into what once had been the throne room and location for Day Court they went, where the differences were stark. All banners, sun or moon, had been removed. The thrones pulled off the dais, an immense map of Equus in their place. 'Known enemies of Equestria', a plaque said in a bottom corner, and Nightmare Moon realised that the Changeling realm was a deep, bloody red. Sombra's Crystal Empire was purple, as were the breakaway states in the south, Vanhoover in the far west, and Stalliongrad. The two halves of Equestria were a sunny yellow and a royal blue, respectively.
The frontlines looked disturbingly accurate.
Finally, in the very centre of the room was a table. There sat three of Equestria's five Alicorns. No, all four. Flurry Heart was hidden underneath her mother's right wing, the one facing away from the Nightmare but peeking out from behind Cadance's protection. Cadance was focused on the table itself, deep in thought. The lucky dears had managed to escape Sombra's resurrection, though Shining Armor had paid with his life to make that possible. Unfortunate.
Sunrise Sparkle, once Twilight, was clearly on her mentor's side of the table, staring at the dark Alicorn with a clear expression of surprise and curiosity, and some... Nostalgia, too. No matter how hard she tried, she was as open a book to Nightmare Moon as she was to her mentor.
Said mentor, Daybreaker, sat in a way Celestia never had. Nightmare Moon hadn't seen the Sun's mistress since the conflict started, and had only heard rumours about the transformation. Flaming mane, the armour no longer golden but a darker, orange metal or alloy. She couldn't see Daybreaker's cutiemark, but it too had likely changed. But all these things were merely superficial. Celestia had always had a kind, benevolent presence. It was easy to feel comfortable and open up in her presence. Daybreaker, on the other hoof... The best word was imperious. She was the single most powerful creature on the planet save for perhaps Discord, and she knew it. She sat there as if she knew that everything and everypony would be subordinate to her in due time. Even at her peak Nightmare Moon had barely been able to best the unaugmented Celestia.
Daybreaker was likely to be a whole other class. Yet here she was, under the banner of Truce.
Nightmare Moon sat opposite of her sister, to the left of Princess Cadance. Sunrise and Flurry were secondary in this. Even Cadance was, in a way - her empire lost to a horrible tyrant.
"Sister," Nightmare Moon said.
"Sister," Daybreaker answered.
They sized each other up for a time. Much like the frontlines for the past months, neither Alicorn moved much at all. Nominally, both knew Cadance was intended to be a neutral party, but the Alicorn of Love would be unable to stop either of the tyrants if they attempted anything. The tension was palpable.
Finally, Daybreaker broke the silence. "You know what is happening in the far west. You are aware of the Changeling threat."
"I could simply wait until you were forced to move enough troops westwards. You cannot sustain a prolonged war on two fronts," Nightmare countered.
"I cannot, but neither can you. Sinister is rousing the rabble against the Gryphon colonies. It is only a matter of time until he looks south," came the reply.
"Yet Sombra is looking to end the great experiment himself. He will weaken himself quite spectacularly, even if he does subdue those radicals."
"What then? Will you open hostilities with his forces as I and mine succumb to Changeling attack, and your own are preoccupied with what remains on our shared front? Not to mention Aztlan and the Confederation in the south. They will be like sharks, smelling blood."
"Such is the truth. Truth is also that I know why you called me here. Truth is that such a thing would see all foes brushed aside. Regardless of all this, I wish for you to say it. A millennium and countless dead too late, Daybreaker, you will say it into my face. And you will know, had you but swallowed your pride, things would be so very different. And I shall give my answer then," Nightmare explained, expression like the cat about to eat the canary. "And not a moment sooner."
Daybreaker frowned, and for a split-second the temperature in the room rose noticeably. Nightmare continued to look rather smug, imagining the marble underneath the solar Alicorn's hooves softening. "You who stole my sister from me not once but twice, who are you to demand anything from me?"
Cadance looked between the two, trying to find words, something, anything, to convince them to stop this posturing. Even Sunrise looked more than a little unnerved. Flurry was hiding under her mother, shivering.
"Who are you to refuse what I can offer? Tell me, oh Empress."
"I am the queen, and the leader of heaven and earth. I am the torch, and the bringer of light. I am the saviour, and I am mother to all," Daybreaker intoned. "I am the new world order to come. I am the first and the last. I am the Empress of the Sun." A pause.
"You are the queen, and the leader of the skies and night. You are the shadow, and the bringer of dark. You are their prophet, you are their love and their sin," she spoke, almost musically. "You are the new world order to come. You are alpha and omega. You are the Empress of the Moon."
Both celestial Alicorns stood, walking around the table, keeping opposite of each other. Together, "Our Empire's rising, their world is dying, in the blink of an eye. We are the sword, we are fire and ash, we are death and rebirth." They kept circling around, magically unfurling new banners from the ceiling. "We are warfare, leaders of battle and hell. We are divine, light and shadow, the first and the last."
They stopped, Nightmare smiling at her counterpart. "You are the Sun."
Daybreaker raised an eyebrow. "You are the Moon."
"We are the new world order to come, the first and the last. They shall come, they shall kneel, and they shall know: our Empire's rising, their world is dying, in the blink of an eye. We are their gods."
They had switched places. A wide-eyed Sunrise Sparkle now sat besides Nightmare Moon. Cadance's head swivelled between them, ears splayed. The two tyrants bowed to each other, each smiling.
"It seems to me that even in these times the magic of Heart Songs is not to be underestimated, Daybreaker dearest. It appears to me we have found a concord."
"So we have, sister. Our foes shall tremble before us."
The laughter of two immensely powerful creatures echoed from the palace shortly after.
"Why is this taking so long?" Chrysalis demanded from her subordinate, the poor drone looking harrowed enough already.
"We need to wait for the target to accept the call, your magnificence. If he will not permit the messenger to enter, there is nothing I can do."
"Just-" the Queen began, interrupted by the sudden appearance of King Sombra on his throne. A magical relay call, intensive in drones but permitting nigh-instantaneous communications. With images!
"King Sombra! Thank you ve-"
"Shut it, bug. I know what's going on and what you want. My spies use methods and magics not seen in an aeon. Nothing you say will be new to me."
Chrysalis recoiled, taking a step back. Anger flared, "The impertinence! You don't even know who or what you're dealing with, little king!"
"I know exactly, which is why I will treat this... 'Call' with the seriousness it deserves. None whatsoever." King Sombra sat lazily in his throne, looking at Chrysalis' projection with contempt.
"You...!"
"Queen Chrysalis of the Changelings, self-styled empress. Greedy, devious, arrogant, vindictive. Above all, a completely untrustworthy creature. I will not speculate on what might have been if things were different. You miscalculated. The Sun and the Moon combined their might. Your destruction is certain, and only a matter of time," he spoke.
Chrysalis swore loudly, making several nearby drones - one even an admiral - blush.
Sombra continued as if he hadn't heard. "Similarly, the end of my empire is inevitable. Thus, contingencies are being put in place. While you and yours are... distracting the Alicorns, I feel other parts of the world might be more amenable to my style of rulership. Perhaps you might wish to have a submarine ready to carry you to that quaint little Changeling state in Griffonia? Greneclyf, I believe it was."
"I'll never consort with that filth!" The Changeling Queen was fuming, but Sombra had taken her off guard, and was exploiting this with audible glee.
"As you say, my dear. Well, I've things to do, socialists to crush, plans to prepare, minds to control. I'll see you never," the dark King said, a blast of shadow magic ending the call quite suddenly.
"The drone's gone, my Queen. He, he destroyed it."
"I can see that! Now get out of my sight, I, I..." she grasped for words, even as the changelings in the room all scrambled to leave by wing or hoof. If only she could send her legions to crush that abomination and his crystals. If only. "I need to plan," she said.