The air in the empty Castle of Friendship crackled, and then suddenly burst open into a violet sphere. Twilight and her friends tumbled out onto the floor.

“Ow, Twi, I think yah need some practice,” said Applejack, standing and rubbing her rump where she had landed on the stone floor.

“I feel sick,” whined Fluttershy. “Ooh- -I think- -”

Rainbow Dash clapped her hoof over Fluttershy’s mouth. “A Pegasus never throws up.”

“Sorry, girls,” said Twilight, panting. “That was my first real long-range teleportation spell.”

“Dear, it was fine,” said Rarity, attempting to put her hoof on Twilight’s shoulder. The disorientation of teleportation travel, however, seemed to have caused her to have temporarily lost her ability to balance. Pinkie Pie did as well, but seemed to actually be enjoying her disoriented state.

“So much spinney,” she said, flopping on the floor and laughing.

“Did you bring the crystal?” said D27. He had not traveled with them- -Twilight doubted that she could move whatever type of alien lifeform he was properly- -but still seemed to be waiting them in the shadows of the hall. He had not bothered to assume his pony form; instead, he was a broad, armored, bipedal creature with no obvious head.

“I did not know that you could teleport,” she said.

“I can. But I did not in this case. I was already here.”

“But if you’re here,” said Rainbow Dash, pulling her saliva-covered hoof out of Fluttershy’s mouth. “Are you still…there?”

“Yes. I am many places right now.” Then he repeated: “do you have the crystal?”

“Yes,” said Twilight, producing it from a set of saddlebags that were attached to Applejack. She moved to give it to D27, but he raised his hand- -which consisted of two long, pointed fingers.

“No,” he said. “Not yet. It prefers you.” The pair of triangles on his upper torso seemed to shift, staring at Fluttershy, who recoiled form his gaze. “Where is this map you spoke of?”

“Before we go,” said Twilight. “You need to understand. We weren’t trying to hurt you. It wasn’t a trap- -they- -we- -really were trying to be your friend.”

“And yet when Celestia sent you to murder me, you attempted to do so without hesitation.”

“We thought…” said Rarity, unable to look up at him. “Well, when we saw you…”

“You could have said something,” said Rainbow Dash angrily.

“You could have asked. But instead, you just assumed that I was evil. It is not a problem, though.”

“Really?” said Fluttershy, looking momentarily hopeful.

“Yes. I am not angry with any of you. You helped me remember what I am.”

“And what is that?” said Twilight, momentarally sharing in Fluttershy’s hope.

“A weapon,” said D27. He did not say it with anger, but as a cold, emotionless declaration. “I am a device created to destroy. It is my only function. You helped me realize that ‘friendship’ is beyond my design parameters.”

“That isn’t- -”

“Just take me to the map so I can do my job.”

“Right,” said Twilight, looking down at the floor. She motioned for her friends to follow her, even though they already knew where their shared throne room was located. D27 followed behind them, lumbering slowly through the halls.

“Don’t worry, Twilight,” whispered Pinkie Pie. “After this is all over, I’ll throw the biggest party ever, and we’ll knock that angst right out of him!”

Blackest Night, Cadence, and Shining Armor were already waiting in the throne room. Based on how wide Shining Armor’s eyes were and how much he was shaking, it was obvious that he had been teleported in beside Blackest Night.

Twilight and her friends took up their positions arouond the table, and the map of Equestria a appeared before them. Cadence and Shining Armor stood beside Twilight, and Blackest Night and D27 stood at the other side of the table- -roughly around Fluttershy, who was rapidly sinking below the table.

“Right,” said Twilight. The map below her activated, showing all of Equestria in miniature.

“Oh, wow,” said Cadence. “It’s beautiful.” She leaned in close toward the tiny model of the Crystal Empire- -where an inch-tall version of her palace stood in perfect detail. Twilight did not have a magnifying glass, but she knew that if she looked, she would even see a tiny crystal heart in the base of the tiny palace, rotating slowly.

“The landmarks are not the same,” said D27. “Too much has changed since I was last here.”

“There,” pointed Nightmare Moon toward a chaotic looking structure in the distant mountains, far away from everything else. “That is the City of Ruins. It is where the Citadel used to be.”

“Then that means that the Finality Core should be here,” said D27. “But I checked there. I found nothing.”

“Applejack,” said Twilight. “The crystal?”

Applejack withdrew the crystal from her bag. Almost as soon as she had, it drifted over the map on its own volition and stopped over the point where D27 was pointing.

The map suddenly shifted. Parts of it moved, drawing apart, with boundaries re-drawing themselves. A circular territory formed near the crystal. For a moment it looked as though the crystal had burned a hole into the map- -there was nothing beneath it but a representation of gray, lifeless earth- -but then a number of towers appeared, as well as a crooked mountain.

“That’s it,” said D27. “The cerorian city, and Olympus.”

“Wait,” said Rainbow Dash. “You mean like the flying city? From the stories? Like, where the gods lived?”

“It has not flown in a long, long time,” said Nightmare Moon. “But yes. It is.”

“So. Cool.”

Twilight looked closely at the dead location on the map, and shivered. Overhead, she could see the tip of a circular black object. From above, she could see the circle that surely represented where the Finality Core was buried- -and knew that it was just as massive as it had been in D27’s memories.

D27 flicked the hovering crysal, and it overlayed a complex map over the dead area representing the number of spells that covered the area. There were so many that it essentially just cast a flat bluish light on the map.

“Coprolite,” he said.

“That is a lot of spells,” said Twilight.

“It would take us decades…no, centuries to cut through that,” said Shining Armor. He looked up at D27. “And no, you definitely would not make it through.”

“Not in time, anyway,” said Cadence.

“That’s where my plan comes in,” said Blackest Night.

“No offense,” said Shining Armor, “but it probably took Celestia centuries to do this…not even you can get through it.”

“Yes I can,” she said. “Because it was Celestia who made it.”

Pinkie Pie moaned. “I can’t take the suspense anymore,” she said, “and all this stuff about magic is making my head hurt. I feel like I’m back at school- -and I hated school.”

“Um, Pinkie,” said Rarity. “Weren’t you homeschooled?”

“Exactly,” grumbled Pinkie.

“Celestia’s magic is limited by her psychology,” said Blackest Night. “The greatest single driving force in her life is to protect Luna at all costs.”

“So the spells won’t affect Luna,” said Twilight, smiling out of the brilliance but terrified from that critical weakness- -even though it did explain how easily Nightmare Moon had been able to betray Celestia one thousand years earlier.

“And I have Luna’s body,” said Blackest Night.

“Ah heard ah ‘probley’ in there somewhere,” said Applejack.

“Yes, well, there is a possibility that there are some anti-Luna spells meant to keep Luna away,” admitted Blackest Night. “Or that the spells might not recognize me as Luna. If ninety percent fail to fire, though, D27 and I should be able to cut through the rest.”

“But that doesn’t help with anything already inside the Finality Core,” noted Twilight.

“No,” said D27. “It would not.”

“And how exactly are you going to destroy it?” asked Cadence.

“I say we sanctify it with dynamite!” said Pinkie, leaning on the table and appearing as though she were about to lick the Crystal Empire.

“I will figure that out when I get there,” said D27.

“I’m going with you,” said Shining Armor. Everypony immediately went silent and looked toward him.

“Why?” they asked.

“Were all of you seriously considering allowing Nightmare Moon and this ‘D27’- -which, if you recall, has already destroyed Equestria- -walk into what has been explained to me as the most devastating weapon ever conceived? Alone?”

“Well, when you put it that way…” said Rainbow Dash.

“Another mage would be helpful,” said Blackest Night.

“Shining, are you sure?” said Cadence.

“You and Twilight can handle administration until we get back.”

“The chiropteran and demonic forces are self-sufficient,” said Nightmare Moon. “It falls to you to command the remainder of Celestia’s military and the griffons.”

“Griffons?” said Rainbow Dash, suddenly interested.

“Do you think you can handle it?” asked Shining Armor.

“I’m the princess in this relationship,” said Cadence, frowning. “Of course I can handle it.”

“Twily?”

“I’ve read books on tactics and strategy. I don’t think it will be a problem.” She looked up at D27. “If you think you can do your part. And just know that I have your entire set of memories. I know about your ‘plan B’.”

“Then you know how damaging it would be to me. But I will do whatever I have to in order to safeguard this land- -even if it means a mass extinction once again.”

D27 reached into the map and removed the crystal. The space below it was swallowed up by the rest of the map, once again vanishing- -but he had confirmed the location, and knew that the crystal now contained the necessary coordinates for him to locate his target properly.

Blackest Night turned her head behind her and detatched her skirt from her armor, revealing a set of interlocking armored plates beneath. She folded the lower half of her dress carefully and passed it to Rarity, keeping only the hard parts of her clothing.

“Take care of that,” she said. “I have grown rather fond of it.” She turned to Shining Armor. “At my side, knight,” she said.

“Technically, I am a prince,” said Shining Armor.

“Not until you grow a pair,” said Blackest Night, stretching her own wings. Rainbow Dash snorted.

Shining Armor crossed the room and stood next to Blackest Night, opposite of D27. He looked up at his wife and his sister.

“I’ll be fine,” he said.

“You had better,” said Cadence.

Blackest Night spread her wings, putting one over Shining Armor and the other behind D27. The air crackled and hissed as her magic surrounded them in a spell profoundy different from Celestia and Twilight’s teleportation spells. Black smoke surrounded them, and then dissipated, showing that they had indeed departed.

“I don’ like this,” said Applejack.

“None of us do,” said Cadence.

“Yeah,” said Pinkie Pie. “I wanted to go too…”

At the windy edge of a long-forgotten radioactive city lit by the luminescence of the moon above, the smoke recondensed. D27 stepped out of it first, followed by Nightmare Moon. Shining Armor fell out onto the rocky ground.

“What the hay,” he muttered, shaking. “Why does that hurt so much?”

“Stop whining,” said Blackest Night.

“Blackest,” said D27, “the radiation we went through was rather high- -are you sure it was safe for him?”

“His wife is sterile. It is not as though he can have children with her anyway.”

“Wait, Cadence is what?”

The two immortals ignored him. D27 looked out over the landscape.

“This brings back some unpleasant memories,” he said. “I died here.”

“So did Luna,” said Blackest Night. “That is the real reason Celestia used it, if you were wondering. To bring her back.”

“I know. It was not worth it.” ‘

Shining Armor stood up, shaking slightly. He seemed to be far colder in the wind than the other two.

“Stand near me,” ordered Blackest Night. “Even after all these millennia the city is still dangerously radioactive. I will do my best to reduce the amount you absorb, but this type of spell generally falls under Celestia’s jurisdiction.”

Her horn glowed, and she cast the spell, shielding Shining Armor from the deadly radiation. She ignored D27; she was already aware that Choggoths were immune to such petty forms of damage, as was she.

“This is incredible,” said D27, staring out over the dessert. “This level of magic…it must have taken millennia.”

“And yet she did it without Luna being aware of it in the slightest.”

“You can see them?” said Shining Armor.

“Of course,” said Blackest Night and D27 at the same time.

Blackest Night stepped forward, Shining Armor following her. D27 trailed behind for obvious regions.

“Let us pray that this works,” she said.

“It might not?” said Shining Armor.

“No idea,” said Blackest Night, smiling broadly. “Actually, this is rather fun.”

“Not if we die!”

“My body is back in the Gloame,” said D27.

“And I can reincarnate,” said Blackest Night.

“I can’t,” whispered Shining Armor.

“Then say high to Satin for me.”

Blackest Night stepped forward past the border that Luna’s sister had created. All throughout the circle of influence, she saw the trappings of the spells ignite, like narrow silken threads spun by some impossible spider. She felt the spells rise against her, and the force of Celestia’s familiar magic rise from the ground, pouring toward her.

She stepped forward without hesitating, though, and as she did the threads and machine-like three-dimensional glyphs around her started to move out of her way. The machine that Celestia was indeed watching her, but, as she had anticipated, it did recognize her as something that it could never destroy.

Which was not to say that the spells did not affect her. Many of them poured into her mind, trying to force her back. Her horn glowed with power as her ancient trihorn mind rapidly analyzed and reversed them. She looked down at Shining Armor, who was huddling against her body in a way that made her uncomfortable.

“Shining Armor,” she said. “Is that horn on your head for decoration or are you going to use it?”

“Right,” said Shining Armor, activating his own magic and doing what little he could to drive back the spells.

“I can help too,” said D27.

“No,” said Blackest Night. “A surge of Order here would be devastating.”

“Not what I meant.” He raised one of his claws and three tiny crystals emerged from his flesh. They formed a triangle in the space that had already been cleared and opened a portal. Immediately, hundreds of tiny blue fleshy insects poured out, swarming into the spell around them.

The spell reacted, fully energizing itself against the oncoming threats. All around them the tiny creatures ignited in celestial fire. With the spell distracted, defensive parts of it drew their power away from attempting to repel “Luna”, allowing Blackest Night to move faster.

“Are those…” started Shining Armor.

“Pieces of myself, yes,” said D27. “And I can feel every single one of them getting vaporized. So I would appreciate if you would work quickly.”

They moved slowly but consistently, crossing the pitted, ancient desert where no plant had grown for over one million years- -following the same path that Celestia herself had crossed twice before. Blackest Night stood in front, plowing her way through the spells in her path, with Shining Armor assisting and D27 following.

Eventually they crossed the final circle of spells. Sensing it, Shining Armor collapsed. Blackest Night was actually rather impressed by his stamina- -even she was feeling tired from the exertion. She dropped to her knees for a moment to rest.

Before them sat the upper edge of the Finality Core. In ancient times, Celestia had spent decades of her life unearthing it, but in five and a quarter millennia the endless wind had buried it once again, only leaving the top most portion exposed, a vast bulkhead of black material that was neither metal nor stone.

“Seven,” said D27.

“What?” said Shining Armor, standing weakly.

“Seven. That is how many Finality Cores I have seen. I have created six, and witnessed this one.”

“How big is it?” asked Shining Armor.

“About one tenth the size of the sun or moon,” said D27.

“And we’re going to go in there.”

“Yes.”

D27 approached the black surface. It had no doors and windows, and initially did not react to his presence. He forced more Order into it, however, and the material started to shift. It drew upward, extending and splitting, forming a door with a ramp to the dark depths below. Sickly, rotten air poured out- -air that smelled of long-contained Order.

Blackest Night stood, and joined Shining Armor as they followed D27 into the Finality Core.

D27 pushed his way through the “hallways”, forcing them open with his presence. He knew that they were not actually walkways, and not really meant for walking. Like the channels in his own “castle”, they were designed for the flesh of a living Choggoth to flow through, to power and maintain the Core until it entered its final stages. That much, at least, he understood- -but still shivered at the idea that his own body had six times prior passed through such channels.

Blackest Night followed behind him, her body almost invisible save for the glint of her armor or the green-blue glow of her unblinking trihorn eyes. Shining Armor maintained the rear, lighting it with his horn, instinctively prepared to defend his queen from any attack- -not that anything could survive very long within a Finality Core.

“Something feels wrong about this place,” said Shining Armor.

“I feel it too,” admitted Blackest Night. “It feels the same as it did the first time I was here.”

D27 felt nothing. “It may be the metal,” he said, knowing fully well that the structure was not truly “metal” at all. “The alloys used are not native to this reality. You may be having a reaction to them.”

“Perhaps…” said Blackest Night, clearly unconvinced.

“You were here before?” asked Shining Armor, trying to make conversation, if only to drown out the droning of the machines that came from deep within the Core.

“Twice. Once when Luna and Celestlia took refuge here as fillies- -although, back then, they were Lunar Vision and Solar Spectra. Then a second time, several decades later.”

“Was it always this terrifying?”

“Yes,” she said. “Luna hated it, but Celestia…she became obsessed with it. I never truly understood why.”

“I generally attribute it to the search for power,” said D27, dismissively. With the number of skulls imbedded within him, he knew all too well what Celestia had used the Core for- -and knew that he probably would have done the same.

“Perhaps,” said Blackest Night, “or perhaps not.”

D27 reached into his body and removed the crystal. Activating it, he examined the schematic and turned right. “This way,” he said, walking into a solid wall that rapidly reformed to accommodate his presence. The halls farther away- -where Shinning Armor stood- -began to seal themselves as the detoured pipes and conduits began to return to their original position, straightening and linking back together.

“This structure has substantial modifications,” said D27 as he passed through several rooms filled with clearly non-Choggoth equipment.

“Celestia spent her life rebuilding it.”

“She was bizarrely prolific, then,” said D27. He had an understanding- -at least on a subconscious, instinctive level- -of all the machines surrounding him. There were far more than one pony should have been able to construct in just one lifetime.

The hallway suddenly opened to a much larger room. D27 checked the schematic. It seemed to be a central control room, which was in itself odd. A Finality Core generally had no need for such a location, simply because such a thing was of no use to a Choggoth operator.

The room was filled with traces of magic, although not all of it Order. D27’s attention was drawn toward the ceiling, toward a number of retracted metal needles. He sent a command to the systems overhead, and one extended. He reached up and removed it, and saw that the needles itself was connected to a glass-like case containing a severed unicorn horn. Most of them, though, appeared cracked and useless. The fact that unicorn horns were present confirmed his suspicions: this area had not been constructed by Nil, but by somepony else.

“Dear Celestia,” said Shining Armor. D27 momentarily thought that he was referring to the horn, but saw that Shining Armor was across the room. D27’s eyes modulated themselves to the darkness, and saw, to his great surprise, a skeleton at Shining Armor’s feet.

“What is this?” he asked, returning the needle to its normal location.

“It was here before,” said Blackest Night, looking down at it. “I never did know who it was.”

D27 examined the skeleton carefully. Just by looking at the skull, he could tell that it had belonged to a trihorn- -which, in itself, was an impossibility. It also appeared that the skeleton itself mostly consisted of metal and numerous exotic cybernetic components that had once been connected to the remains of internal organs that had long-since rotted away. Assessing the technology, D27 concluded that it was probably powered by or operated in concert with strong magic.

He reached down and pulled the skull out of the metal clips that held it against the thick metal spine it was connected to.

“What are you doing?” said Shining Armor.

“The trihorns died before Nil did,” he said. “All who were living were shattered. No skeletons remained- -and yet there is one here, now.”

D27 looked into the empty eye sockets of the skull, and at the three horns that protruded from its head. Superficially, the trihorns did somewhat resemble large ponies- -but without skin, it was obvious that they were far more reptilian in nature.

“Are you sure that is a good idea?” said Blackest Night, knowing what D27 was contemplating.

“I have to know,” said D27. Then, taking a deep breath, he pulled the skull into his own body.

The sound of machines. The endless sound. Always whirring and clanking. Machines that he had built- -and machines he had not, and machines that he had never managed to find even after decades of searching.

“What is taking them so long?” he muttered to himself. He had sent the constructs out, but they had not come back- -but he was not sure for how long. The machines demanded more parts- - more metal, more pieces, more horns.

In his head, the images were flashing by rapidly, annotated by voices that he could not understand. He knew which machines needed to be built and what they would do in an abstract sense, and knew what parts he needed- -but the parts had not come back yet.

Arcane Domination pushed his way through the material surrounding him, reveling at the way the metal responded to his power- -but for some reason feeling deeply anxious, and deeply terrified of it. He attributed it to the failure of the society above. They just did not make him enough parts anymore.

At that point he stopped. His mind nearly grasped something, something that he knew was critical but could not recall, something that he had not recalled in a very long time. The whispering stream of endless voices in his mind increased in intensity, but seemed somehow far more distant than they were supposed to be.

Before, they had been voices. Real ones, ones that he heard speaking to him. At first he had hated them, and feared them, but then he realized that they were good voices, voices that came from within himself- -but they had left him a long time ago. They were replaced with the whispers, which were different. They spoke not in words but in thoughts, needs, and ideas. They were what drove him to construct, to build, to complete the Finality Core.

He pushed his way into the control room. For some reason, it had gone silent. The machines were all falling silent, shutting down, and he did not know why. For years he had worked so carefully to repair them, treating them far more lovingly than he had treated any living thing. Even with all his care, they betrayed him by slowing their churning.

“Why are you doing this to me?” he asked. His voice sounded strange, even to himself. He shook his head. “No. I don’t care. I will succeed. I have to SUCEED!”

He froze again, the feeling of almost knowing crashing through his mind. Something was wrong, but he still could not remember.

“It has to be this way,” he said to himself. “Subject can no longer continue operation. Setting Core to dormancy. Need a new one…”

Arcane Domination shook his head again and cried out in rage. He did not understand what was going on, and that filled him with nothing but anger- -he was supposed to know everything. No being in all of Panbios knew more than him, especially concerning the Finality Core. Yet, even after several years of research, he had gotten no farther. Every mystery about the Core he solved opened ten thousand more; every machine he created filled a missing piece from some greater incomprehensible thing, but never performed adequately to bring the Core to its full power.

“At this rate, I’ll never reach my goal,” he started. Then he started screaming uncontrollably.

At first he did not know why, because something in his mind was blocking him from knowing- -but he was still intelligent, and rapidly came to understand what he had spent so long searching his mind before. He had forgotten what he had ever come to the Finality Core to do in the first place.

He collapsed on the control podium near the altar that contained his carefully constructed models of the sun and moon, beneath the projector he had lovingly built from the severed horns of monohorns. He gasped, but realized in doing so that he could no longer feel the cybernetics that were keeping him alive.

“No,” he said. “No no no no…I came here to…to do what? What?”

As much as he tried, he could not remember. As he tried, though, other things slipped past what he had accepted as the boundaries of his mind.

“How long?” he asked himself, realizing that he did not know how long he had been at work. He seemed to have lost track of time waiting for his magical constructs to return with more parts- -but he was unsure of how long they really had been gone, and had absolutely no reference for how long he himself had been in the Core.

“You actually don’t know,” said a voice that came from his mouth but that was not his. It was strange and nearly female, and he recognized it distantly as the voice that had guided him in the early days. He shudder as an image passed into his mind, one that he now realized he had seen countless millions of times before- -a complex soup of geometric shapes that he somehow considered to be an eye.

“Who are you?” demanded Arcane Domination. Then, realizing in horror that he did not know: “Who am I? What am I doing here?”

“Five hundred and sixty four years seven months three days four hours and thirty seven minutes since loss-of-contact,” he said back to himself. “All that time, and you were so obsessed that you never even noticed.

“Where are you?” he demanded. Distantly, he was aware that he had once been something great, something powerful, but he did not know from where. All the memories he had were from within the machine.

“Let me show you.”

The walls of the control room shifted, their metal separating into arm-like divisions. They produced a fragment of plating that was highly polished, like a mirror, and lowered it in front of Arcane Domination.

“No,” he whispered.

Before him, standing in the mirror, was something that was not him. The tubes of his cybernetics had long since been pulled out of him, and he even remembered how he had used bits of them to repair the machines. There was nothing left for them to connect to anyway. The flesh on his body had long since rotted away, being replaced by synthetic pink flesh that held his bones of implants together and allowed him to move. His face had been stripped away, revealing his teeth, which were formed into a perpetual smile. Both of his eyes were gone- -but one was replaced with a red-pink mass of tissue inscribed with the same complex assortment of shapes that kept recurring in his mind.

“You are dead,” he said, and watched how his mouth did not move in the mirror. He wondered if he was really saying it, perhaps through some unfamiliar and alien auditory organ, or if the voice was simply in his mind. “Eight thousand years you have been down here, with me. I have kept you alive to do what I cannot do alone. But now there is nothing left. Your mind is a shadow of my own. You are incapable of magic, or independent thought, and yet you somehow refuse- -or are unable to- -realize it.”

The calm and clinicallness of the voice was infuriating, but Arcane Domination hardly noticed. He raised one bony, skeletal hoof to the mirror, and saw that his reflection did the same.

“I’m sorry,” he said.

At that moment, Nil withdrew itself from him. Just as the last spark of life left Arcane Domination’s skeleton, his memory returned just enough to recall who he had been, what his goal had been, and the fact that he had failed.