Black Sun

Twilight gritted her teeth slightly as she paced through the halls of Canterlot Castle. She should have moved to do this days ago. As much as her friends had done their best to support her, she knew that all those deaths were her fault. Because she hadn't thought of this while there was still time. Just as importantly, doing this now meant that Pinkie's sacrifice wouldn't be for nothing.

In the aftermath of the attack on Ponyville, it had taken far longer than it should have for her to snap out of her despair. Even if she had traumatised herself over how she had handled Starlight Glimmer all those years ago, she should have known better than to let it get to her like that. Every single one of those lives that had been changed or ended by the events of the past few weeks...She owed it to them to lead clearly, plan with finality, and make sure the darkness Tantabus was spreading would be contained for good. Up until now, her efforts had been focused on coming up with a spell to safely separate Tantabus from Sunset Shimmer and force her to return to Luna. The hard part was the doing it safely, yet she had effectively sacrificed dozens of lives to the mere chance that she could save one. She couldn't afford to waste any more time.

Twilight furrowed her brow further and increased her pace, glancing aside to check the small chest held under her wing. Deep Note had brought it all to Canterlot as per her instructions the morning after the attack, the most important key to their success right now. Every last piece of her studies and everything relevant Pinkie and Apple Bloom had recovered from her library was inside, everything needed for this part of the plan. The basis of the spell she'd made was written down, now she just needed to see if the most powerful magic user alive would be able to improve it. If not...It was ready to use, ready to stop more lives being taken no matter what. Sunset had been a student of both herself and Celestia, she understood the value of self-sacrifice.

Twilight straightened up and tucked the chest closer to her as she approached the doors to the throne room. The doors were closed and a pair of guards were standing on duty in front of them. Her mood sank slightly further as she got close enough to see one of them was Iron Vixen. She was a living reminder that even with all the names permanently etched into the princess' mind, there were more that had fallen before she had even become a part of this. Even more names she needed to learn, and avenge.

"Captain," She said as she approached. Both guards saluted her before returning to attention again. "Are the princesses available right now?"

"Yes your highness," Iron replied. Though the mare maintained an air of professionalism, Twilight could tell she was fighting the strain of being forced into command. "They're currently between court sessions, but you were cleared to enter at any time."

"Thank you, and don't worry. We're close to sorting this out."

"I hope so..." Iron said quietly, her façade slipping for a moment as she fought back a sigh.

Twilight shot her a sympathetic look before moving forward, opening the doors in her magic and slipping inside. It was the first time she had been inside the throne room since Tantabus had jumped into Sunset and the memories sent an involuntary shudder through her bidy. The scars the room bore from that day were still evident. Although the walls, pillars and roof had been repaired and the debris cleared away, they had not yet been covered to match the rest of the room. What was left of the stained glass windows had been removed as well. As bad a state as the throne room was in though, it was nothing compared to the sisters at the far end of the room.

Celestia was sat at the base of the steps to the twin thrones, eyes shut in focus, mane still, a trail of magic running from her horn to Luna's chest. The younger alicorn was slumped in her sister's arms, side rising and falling gently as if she was peacefully asleep. She looked as though she hadn't slept for a month, and Celestia looked as though she'd had her share of sleepless nights too. The sight of the two, normally so serene and unflappable, reduced to holding each other like frightened fillies punched a hole straight through Twilight's heart. She had enough of a grip left to close the doors behind her before the chest slipped out from her wing and clattered to the floor.

"Who...?" Celestia started, opening an eye and turning toward the door. On seeing who it was she relaxed again. "Oh, Twilight."

"I...I'm sorry." Twilight said quietly as she remained rooted in place.

"You have nothing to be sorry for," Luna suddenly told her, lifting her head up. She almost looked as though she carried more of a fire in her than her sister at present. "You've been doing more to try and save me than anypony."

Celestia nodded as the thread of magic she was casting trailed off, her mane returning to normal after several seconds. Somehow she looked even more weary than she had before. Luna seemed to be carrying herself similarly to how she normally did, even being the one helping the other back into a sitting position.

"I..." Twilight looked down for a moment as she tried to think of what she actually wanted to say. The fallen chest caught her eye and she picked it up in her magic, bringing it up to her chest before looking back at the princesses. "Does it hurt?"

"No," Celestia told her reassuringly, managing to smile as she straightened up. "While it does put some strain on my magic, such a spell won't-"

"Sister..." Luna interjected, placing a hoof on Celestia's back and looking up at her with a look of resignation. "I know, that you want to believe everything will be alright. But we can't lie to ourselves, or to Twilight. She needs to know just how serious it is."

Twilight didn't need to say anything. She barely even started thinking about it before she was in front of the princesses, eyes shining with mounting concern. How long did they have? Was it too late already? Had the cost of her stalling become too high? She forced each and every question to one side for now and focused again. This wasn't the time to panic.

"I was trying to keep the pressure as low as I could." Celestia admitted, shifting in place.

"After everything that's happened, I appreciate it," Twilight replied as she placed the chest down. "But, I'm with Luna on this one. How bad is it?"

Celestia closed her eyes and sighed as she weighed up the situation, Twilight and Luna silently watching and waiting. After a few moments she opened them again and nodded, sitting down and focusing her gaze. She wasn't trying to hide the sadness in her eyes as she cast a bubble of silence over the three of them.

"The truth is, we underestimated the damage the jump could cause. We'd both seen them happen in the old empire, but anypony suffering it always died quickly. We believed that lekli withdrawal did damage through the pressure it put the body under but...It's more like a disease, eating away at an alicorn's strength and weakening their magic until they can't sustain themselves."

Celestia squeezed her eyes shut as she finished speaking, her voice wavering. Twilight realised that she had been trying to lie to herself about this as well. That she didn't want to admit she was fighting a losing battle where defeat meant losing her sister, and possibly much more.

"We've been able to stave off the worst," Luna reassured her quickly. "Regular magic infusions have halted its advance for now. The bad news is that Celestia is the only one with magic strong enough to be useable. It drains her as well. The amount needed to keep me like this can't be recovered at the same pace, so it's not an endless supply either."

Celestia merely nodded in confirmation.

"I see..." Twilight commented quietly as she took all this in. "Then, please tell me. How long do we have?"

"As things are...Four months," Luna continued, looking over sadly at Celestia. She looked more solemn with every word spoken. "In truth though, we simply can't keep things as they are. Not if Celestia is to maintain the strength required to raise the sun. It'll only be a few weeks before the amount I can receive isn't enough to help anymore."

"I came too close to losing you forever once," Celestia suddenly interjected, head lowered and mane covering her face. "I don't know if I can do it again..."

In the blink of an eye, everything made a lot more sense to Twilight. Why her former mentor was so distressed by the steadily deteriorating situation, why her sister was more determined to stay strong, why they were both doing their best to face the very possible reality before them. Their fight was every bit as difficult as hers. At the back of her mind, the ever rational part of her realised that they needed every advantage that they could get too, which made her presence here a blessing in disguise. She glanced down at the chest she was still holding and brought it forward.

"You may not have to," She told them as she opened it up. "I put all my free time into this."

"And this is?" Luna asked as she lifted a scroll from the assortment of items inside and studied it.

"A first pass at creating a spell to separate Tantabus from Sunset and safely return her to you."

Celestia slowly lifted her head again at those words, a glimmer of hope in her eyes. She slowly leaned in to look at it over Luna's shoulder, eyes rapidly darting through the weave of magic laid out on the scroll.

"It should be able return Tantabus to you without her escaping," Twilight continued. "Although this version requires a highly inefficient amount of magic to cast, and Sunset would be unlikely to survive. I was hoping to find a way to refine it to save her and return you to normal but, I wasn't aware just how badly time wasn't on our side. With your magic, you might have better luck improving it quickly."

"This is..." Celestia commented as she finished reading through it. It may have been wishful thinking on Twilight's part, but her movements seemed to have a little more energy to them. "You made this from scratch? I believe it could work."

"And with some effort, we should be able to work on it as you hoped," Luna added, smiling slightly. "Some more delicate spell weaving, making it akin to magic surgery, should limit the damage to Sunset. Strengthening it would also limit Tantabus' resistance and avoid untoward side effects."

"Alright, Twilight. We will put our all into this," Celestia told her as she relaxed further, smiling softly. "Once our courts for the day have ended, we shall begin at once."

Twilight allowed herself to smile and nodded, passing the chest over to them. As the sisters ended the bubble of silence and moved back toward their thrones, she kept running through everything she now knew about the current situation. Despite the advances, the real possibility of a way to finish this, the doubts and fears just wouldn't leave her. There wasn't much else to be done at present though and staying would delay the royal court, likely making ponies even more uneasy at the disruption. With that, she made her farewells and promises to continue doing her part before teleporting away. It would be easy to assume she was heading back to Ponyville to continue the fight. In truth, she had something else to check on first. Something that could prove even more important.

As the world returned to focus around her, Twilight shivered as a ferocious cold bit into her suddenly. She was standing on a mountain ledge that seemed to be more ice than rock, a barely visible pathway leading back around the mountain and to the west. While this area was technically part of the territory of Yakyakistan, not even they were hardy enough to venture this deep into the Yaket Mountain Range. She had only learned of this path by sheer chance during one of her exchanges of information with the then-newly crowned Chieftain Yona. That morsel of trivia learned years ago had actually proven a blessing to her, in the way of revealing the existence of the cave she now stood before.

She quickly moved inside, out of the worst of the wind and cold. It was cramped inside, barely wide enough for two ponies side by side and she was forced to duck her head to keep her horn from scraping the ceiling. Twenty feet inside, she stopped and looked down at a pile of rocks that had fallen from the roof, blocking the way too much for her to advance further. She didn't need to though. She lifted some of the larger rocks at the base off to one side and quietly sighed in relief. The box she had left buried there was still untouched. A simple leather case, the kind most ponies would use for larger pieces of jewellery. Twilight glanced back as if she expected something to be there, watching the cave entrance for several seconds before looking back down at the box and opening it.

She didn't touch it, didn't move toward it. She merely stared at it, losing track of time as her eyes remained locked on the old world relic inside. She'd been on the receiving end of its power, heard firsthoof accounts of what it felt like to be under it's domination. Yet...Such strength could be enough for her to overcome Tantabus without risking any more of her friends' lives. Her will was strong enough to suppress what lay within, remain herself as she ended this crisis. She wouldn't be where she was now without incredible willpower. Her hoof slowly reached out, ready to embrace her duty to her home, her friends and family...

And brought it back down to the ground.

"No," Twilight quietly told herself, shaking her hoof as if it might dispel the allure that had fallen over it. "Have faith."

She quickly closed the box again and placed the rocks back over it, getting up and turning away before she could risk such thoughts coming back. She knew in her heart that it would be the wrong decision. Her friends always came through for each other when they needed it most, and now was another of those times. Her hooves shook slightly as she moved back to the cave exit and took several deep breaths to calm herself. There would be no need to take even greater risks like that so soon. Celestia and Luna would improve her spell. Then they would all find Tanabus, free Sunset and make everything right again.

"You don't need it...Rainbow Dash had it right. Since when do we ever fail when together?"

"You don't need this...This defective body. Costing you easy victories over and over."

Tantabus growled to herself as she paced through the rock tunnels that had become her temporary hideout. She had no idea who had created the structure that encompassed them, especially since it was located deep in lands nopony would ever tread. To a regular pony, the area was nothing but hundreds of kilometres of dry rocks, great crevasses in the earth and the taint of dark magic everywhere. Personally, she found it comforting to embrace the darkness around her, utilise it to bolster her power and remind her of home. It had also come in handy for keeping her strength up, letting her keep teleporting away to forage and heal the wounds Cadance had inflicted without any strain on her magic.

"How can you even look at yourself and claim you've accomplished anything like this?" She continued as she entered her 'bedroom', a slightly more spacious area that she'd gathered some straw in to sleep on. "You're supposed to be the best of the defect race and you were utterly devastated by a fake alicorn that would barely pass for a slave in proper circumstances! Now hold still."

Tantabus sat down on her bedding and closed her eyes as her horn lit up, the aura gathering around a burned patch on her back. When her eyes opened again, Sunset was placed back in control. She hissed in pain as all her senses came back to her at once, including the searing sensation of rough healing magic working at the burn. It had been like this ever since the battle in the Crystal Empire. Every time there was a painful part of the healing process, she was given back control of her own body just so Tantabus wouldn't have to feel it. A small part of her cursed the durability the lekli brought; Facing everything they had endured alone would have killed her a hundred times over by now. That was starting to feel like a preferable alternative.

After several seconds the healing was done, the skin back to normal and a thin coat of fur covering it. Almost her entire body had been treated like this by now, only the lightest injuries being left. As soon as the magic faded her body lurched forward as Tantabus retook control without a moment's pause.

"Oh don't go soft on me now. This is nothing compared to what Vaeac will do to you if you're found," She commented coldly as she stretched out. "All the chaos, all those deaths, the spread of fear and darkness through the crystal heart. As far as ponies know, that's all on you."

'You don't know them then.'

That annoying whisper in her mind, the only influence Sunset had when not in control, was starting to grate at Tantabus at this point. She was wrong of course, but she clung to her misguided convictions as if they were as vital as air. The sooner she could find a way to either boost her strength further or get into the Tomb of the Gods, the sooner she could consume this irritant and truly have a body of her own again. One that she would take further than any of her kind before it. She would unlock the secrets her 'sister' held, become a true alicorn again, and spread her dominance across the entire world.

All she needed was some more time. Time to decide where her next strike would do the most damage, and time to get back into fighting condition. Then...Everypony would pay.