There was a moment of silence.
"Okay." Trixie said "We need some concrete information if we want to make any plans that have a chance of succeeding." She looked at her fellow apprentice "Sunset, send Trixie the information you've collected, she will make a prediction."
While the apprentices looked blank at those words, Sunset had an interesting reaction. She hesitated for a period of time so small most ponies would have missed it, but then nodded and started a spell, while looking at Trixie with slight concern.
The spell finished, and she sent a small beam of magic into Trixie's horn. The unicorn looked focused for a moment but then relaxed and looked at Rarity.
"Rarity. Pay attention to this. Trixie intends to help you create your own version of this spell in the future." Having said that, she returned to what she had been doing earlier.
Trixie closed her eyes in a clear sign of focus and started casting spells repeatedly, creating magical symbols in the air. She was also muttering a lot, and Pinkie and Fluttershy thought that she looked a bit like Twilight while she was doing that. The symbols filled the air around her and started moving in strange patterns and shifting little by little, adopting new shapes and colors that got ever more complex.
The sheer size of the formation of symbols also kept growing as she added more and more of them to the pattern, soon the formation grew to the size of a fully three dimensional house, and it was dense enough with symbols that it started getting harder to see Trixie through them.
But they could still see her, and they saw that Trixie was looking more and more strained as she weaved her complex web of magic. None of the others dared to talk, fearing to break her concentration, but their concern about what was happening was obvious, specially if one looked at Sunset.
And then Trixie finally finished the first part of what she was doing.
"Multiplicity Magic: Perfect Database!" She shouted, and stomped the floor, making all the symbols light up.
Lines of light connected the symbols together in a true web of magic, and then they all fused together into a beam of light that gathered right above Trixie's head, turning into a sphere made of thousands of incredibly small symbols. And then Trixie charged magic again, but this time for fifteen entire seconds, gathering so much magic that it gave the feeling of more power than an Overdrive.
"Perfect Illusion: Prediction Formula!" She shouted, releasing a powerful pulse of magic.
The idea behind the spell was simple, by creating a model of the world and inserting into it all the variables involved in a situation in order to literary predict the future. As might be expected, this was an extremely difficult thing to do, and even though Trixie just wanted to predict parts of it, and the fact that the place they were in was remarkably isolated, this was something that took a lot of effort.
As demonstrated by the fact that, as soon as the pulse of magic disappeared together with the entire formation, Trixie collapsed on the ground.
"Trixie!" Sunset shouted, moving to her partner's side to check in on her.
"Trixie is okay." The unicorn said in a weary voice "But she is not going to be up for any heavy spellwork for a while." She got back on her hooves "But the results were worth it." She stated "The temporal cascade is accelerating at a constant rate. According to Trixie's calculations, we have one hour before we are swept up enough in the time loop to be able to affect things without needing to use too much power, but thirty minutes later we would be too linked with the loop to the able to escape it."
"That's not a large time window." Rarity said, seemingly just to try and prevent another awkward silence.
"Right. That means we can't waste any of the time we have." Sunset took charge "We should prepare as much as possible during the next hour."
"Trixie will prepare a few spell circles to help compensate for her strain." Trixie announced.
"That's good, I'll do something similar." Sunset agreed "Dash, you should charge as much magic into a cloud as you can, to prepare to use big spells." The pegasus nodded "Do you have any ideas for Rarity or Applejack?" She asked Trixie.
"Rarity should probably help Trixie with the circles, but Applejack is a different case." She looked to her apprentice "Do you think you can use your Eyes of Truth to keep an eye on things and make sure the escape route is clear?"
"Yeah, Ah can." Applejack nodded.
"Then that is decided." Sunset said "Now there's the other two." She looked at Pinkie and Fluttershy.
"I think we should focus on trying to find Twilight, even if we have to check every one of those ponies." Pinkie said "I think a combination of my Emotion Charge and her empathy should be enough to make a Twilight sensor!"
"Yes..." Fluttershy agreed.
"Okay. In that case we all already have our tasks." Sunset summarized "Let's go!"
And so it was. Trixie, Rarity and Sunset were writing out large amounts of spell circles and runes on the ground and walls for later use, preparing spells which would be sufficiently versatile to deal with most situations (they would improvise in case those weren't enough), Rainbow Dash flew into the sky and created a cloud to inject with magic, in a way she had previously trained with Sunset (the goal of the training was getting her used to handling large amounts of magic, and those were large amounts of magic even by Sunset's standards, so it didn't need to be said how much power she could gather), Applejack was patrolling the part of the city closest to where they had come in, which was the place with the biggest magical gap, their planned exit point, and making sure they would be able to use it when needed.
As for Pinkie and Fluttershy...
"Duo Magic: Empathy Search!" The apprentices of Twilight announced, weaving their magic together.
They were going through the boring and unenviable task of checking on every single one of the ponies in the city. The simple aspect of making sure they weren't going to check the same one more than once already took some effort (Fluttershy had to empathically "mark" those she went through), but even more than that was the simple fact that there were a lot of those ponies, enough to test even the endurance of the Knights, both in terms of magical capacity as well as the simple will of managing to keep going with the same spell dozens of times.
But they kept going, and every one of the Knights did their best in the hopes of being able to rescue the last of their number. The situation of the battle was changing faster and faster as Blank kept getting more powerful, and by the time the hour was done, Twilight wasn't able to defeat her opponent any more, and barely managed to survive each "loop" of fighting by using her magic defensively.
The preparation time felt like it was way too short, but when the hour was over, Twilight's disadvantage was so obvious that they didn't dare to hesitate.
"Triple Magic Enhance: Grand Nova!" Sunset shouted, casting her magic.
She had already entered Trance mode, and so even such a powerful spell did not take long to charge, and the effect was impressive, creating a cone of magical power that was powerful enough to be a threat even to an actual mountain. But of course, Blank had gotten remarkably strong, so even that wasn't enough to break through his defenses.
The stallion simply stopped his attack on Twilight and forcefully created a concave barrier out of his light magic, which exploded when hit by the attack, making most of the energy of Sunset's spell vanish, at the same moment, he also created a disk of magic and threw it at Sunset.
Rainbow Dash detonated it with an overcharged lightning bolt from above to help her teacher, before shooting a dense sphere of lightning at Blank. At the same moment, Sunset and Trixie had finished their spells, and surprisingly, so did "Twilight", who was apparently aware enough to coordinate with the Knights.
"Triple Magic Enhance: Seeker Bombardment!" Was Sunset's spell, and it created dozens of magical missiles that attacked Blank from all sides.
"Perfect Illusion: Fog of War!" Was Trixie's spell, which she could only cast with the help of several magical circles activating at once. And the spell made it so that Sunset's missiles seemed to multiply, also changing patterns and timing, making it nearly impossible to know which were the real attacks to be blocked and when.
"Chaos Magic: Thousand Needles!" Was Twilight's spell, and it created a thousand needles that pierced towards Blank while carrying an explosive power, mixing seamlessly with Trixie's illusions.
This had actually been an attack pattern that the three had worked out, and it was devastatingly effective even against such an opponent. Even though Blank extended his magic to annihilate most of the enemy spells, he simply had no way to create a truly perfect defense, and so a few of the attacks slipped through the gaps.
By the time the triple offensive had ended, Blank had been reduced to a head which was supported by a thin "cloud" of light magic. But then the situation took a drastic turn, as the stallion who had always been silent up to that point suddenly roared.
"UROOOOOOAAAAAAAAGGHHHHHHHHHHH!!" The sound was loud enough to shake the space itself.
And Blank's light magic devoured his head and then shined brightly for a moment, before retreating and revealing that his body had been completely restored. But even that wasn't the worst part.
The worst part was that the pony closest to the battlefield suddenly screamed as his body was overtaken by the light magic, which faded to reveal that he had turned into a perfect copy of Blank.
There was an important reason why Applejack wasn't directly involved in the fight against Blank. She had to remain next to their exit point and prevent it from closing in case of a sudden change, but she still helped with the battle by providing information to the others.
And she was the first to realize what was happening.
"He's taking over Twilight's spell!" She shouted.
The second Blank moved to the side of the first one and then both of them started to throw dozens of light spheres at their attackers, who once more had to turn their energies towards defense to resist this sudden assault.
But Applejack could see that the situation was even worse, because Blank's magic was already slowly taking over the other artificial ponies.
Fluttershy and Pinkie Pie had just finished checking the last pony in the loop when the fight started.
"Why...?" Fluttershy asked "This was the last one, so why haven't we found Twilight yet...?" Her voice was full of sadness.
Pinkie put a hoof on her chin, in thought "Maybe we missed something since the start." She looked at Fluttershy "Are you sure Twilight is in one of the ponies? I have a feeling things aren't so simple. This is how chaos magic works."
"But she has to be inside one of them!" Fluttershy declared with certainty "Which means..." There was a moment of silence as Fluttershy thought about Pinkie's words and arrived at a revelation "That's it!" She shouted "She is indeed inside those ponies, but her soul is shifting between each of them so fast we can't detect her!"
Pinkie nodded, thinking that this seemed right "So what do we do?"
Fluttershy blinked "Well..."
But before she could finish her thought, Blank roared and she saw him taking over one of the ponies.
"He's taking over Twilight's spell!" Applejack shouted at that moment.
"Oh no..." Fluttershy began, and then blinked "Wait, this could actually help." She flew over and grabbed the pony they had previously checked, dragging him back towards Pinkie "With less places it can go, Twilight's soul will be easier to catch. Pinkie, try to keep this one free from Blank's influence." Pinkie saluted and started injecting magic into the body of the pony, trying her best to fight off the power of Blank "We can rescue Twilight!" She shouted to the ones currently fighting "Just hold him off for a bit!" Hearing that, Trixie, Sunset, Rarity and Rainbow Dash started fighting with even more ferocity "Applejack, could you..." Fluttershy stopped talking as she turned back and saw what Applejack was doing.
The worst situation had occurred, and the opening in the time loop was trying to close. Applejack was physically and magically holding it open, but it was clear that she would not be able to hold forever.
"Guess I'll have to do it myself." Fluttershy muttered.
Then she started charging magic while at the same time visualizing her goal.
Twilight. Her teacher Twilight. Twilight's personality and her magic. Twilight's body and soul. Everything that Twilight was appeared in Fluttershy's mind, as she reached deep inside herself to call her empathy to its highest levels.
She would not fail.
"Wind and Earth Style: Dust Storm!" Rarity shouted, slashing with both swords.
Her spell created a thick cloud of dust that blocked the sight of the many Blank copies and also blocked their constant bombardment of light spheres, since it forced them to detonate when they touched the dust. Rarity focused herself as much as possible to keep her defense up as long as she could, because any extra time she was able to give for the others to prepare counted.
Initially, the four Knights (plus the fake Knight) maintained a strong offensive, trying to prevent Blank or his copies from gaining any advantage they could build upon.
"Perfect Illusion: Forgotten Mist!" Trixie shouted, unleashing the full potential of the magic circles.
"Chaos Magic: Hidden Space!" Twilight shouted, warping space with her chaos magic.
Trixie's spell created a dense mist that blocked the awareness of every single one of the Blank copies, while Twilight's spell manipulated space to hide the Knights. Rarity's spell finally broke and she lowered her swords, breathing heavily to try and recover from the immense exertion she had went through. The Blank copies immediately started throwing more and more magic at the mist, slowly breaking it apart, while the original Blank created a gigantic spear of light magic and started stabbing into the manipulated space, making it unravel little by little.
The advantage of the Knights had not lasted long. As more and more Blank copies appeared, even their combined power and skills were slowly overwhelmed, to the point where now they were fighting completely on the defensive. Were it not for Fluttershy asking for time, they would have already tried something reckless to try and reverse the situation.
"Duo Magic: Enhanced Harmonic Blast!" Rainbow Dash and Sunset shouted, mixing their magic together.
As soon as Twilight and Trixie's defense finished being destroyed, the two were already ready to unleash their own technique, which started with Rainbow Dash gathering most of the remaining magic in her cloud and forcefully turning it into part of a harmonic rainboom, that Sunset subsequently enhanced. Their attack was a veritable drill of power, that crashed into Blank's spear of light and managed to destroy it.
The only reason why they were still able to survive in front of dozens of Blank copies was the fact that none of the copies were as strong as the original Blank. But Blank was still getting stronger at an appreciable rate, and they would have no way of holding on for much longer.
Thankfully, it was then that the situation changed.
A pulse of very familiar magic swept through the space, and the copy Twilight nodded and disappeared.
But most importantly, the fight stopped immediately as both sides turned to look at the origin of that magic. And there she was, right beside Fluttershy and Pinkie. Twilight was back.