The Devil You Know

Twilight Sparkle burst into the Royal Canterlot Library, panting heavily as she skidded to a stop. It wouldn't do to damage any of the priceless volumes in her quest for knowledge, so she allowed herself time to slow her pulse and relax before moving purposefully into the aisles. Eyes narrowed, she focused her attention to books that would lead her on the path to discovery as to who this threat is, as well as how to defeat them.

Knowing that the modern tomes wouldn't be helpful to her in this regard based on a hunch in her gut, Twilight Sparkle instead tried perusing volumes that spoke more of the past. Grabbing a stack from various shelves, she sat down at a nearby table and began to read. Magic lights in the library enabled her to see the words on the pages when it otherwise would have been too dark to see from the ambient light because of the all the smoke in the air.

Hours passed in this manner, with the stack of discarded books growing to epic proportions while a steadily frustrated Twilight Sparkle kept trying with older and older editions. Finally, in desperation she grabbed an ancient looking book that covered her in dust when she yanked it off of the shelf it sat on, half hidden in shadow behind a few forgotten volumes about the Sweet Apple Acres farm. Sneezing, Twilight sat down and carefully opened the book with her magic since it seemed like her hooves would crumble the paperback into pieces.

At first, it seemed like an ordinary history detailing the battle between Celestia and Luna when the latter of the two princesses had been banished to the moon, but looking closer Twilight realized there was more to this story. In her mind's eye she saw the battle, but the words on the page spoke of something else that had happened as Celestia declared victory over her sister. A birth of something else, a creature within Tia's mind that seemed to have its own thoughts and actions.

Celestia had fought long and hard to win control over this being that resided within her soul, but there were weaknesses to the blockades within her mind. Weaknesses that over time would be eroded, and the caged monster within could use that as an opportunity to break out. Twilight carefully turned the pages, eyes huge with mingled fascination and horror. This being had over time come to name itself, but only Luna knew the identity of the creature that seemed to be a darker image of the royal princess who's job it had been to raise and lower the sun.

What if.... that was what was attacking Equestria? Who would know better the battle strategies of the kingdom, the fastest ways to bring the nation to their knees than their own ruler? Twilight sat back in her chair, thunderstruck. If Celestia was now their enemy, what chance did they stand to stop her? Was that why so many guards had lost their lives? Did they recognize their solar diarch and hesitate? Hundreds of questions tumbled in Twilight Sparkle's mind, unable to be answered.

After several moments sitting there, Twilight burst forward and flicked rapidly through the pages, searching for a way that this creature who lived within the beloved princess could be stopped. Faster and faster she moved through the little book, her expression falling. Nothing. There was nothing here. No way to stop--Wait. Twilight Sparkle narrowed her eyes, trying to decipher the blurred manuscript. Something was here. Something that suggested a way to stop the evil within.

The lavender unicorn could only see what looked like one word, and the meaning of it was lost to her. Closing the book with a snap of her raspberry magic, she floated it back to the shelf it sat on before standing. The word was burned into her mind, but it was shoved to the back while she took a breath and steeled herself for her report to Princess Luna. Just what was Pōwehi anyways?

Princess Luna hesitated before a map of the city. The fires were slowly becoming contained, but a lot had already burned. Figurines marked all the spots that had been reduced to ash, and smaller ones depicted the piles of bodies in the wake of the enemy leaving a trail of carnage in their path. Others still marked the overall pattern, trying to make sense of the sudden chaos that had struck in the night, and lingered on into the blossoming dawn.

Her cyan eyes were full of worry as she realized that in just a relatively short time, this fearsome foe had nearly crippled them and all but decimated the heart of the populace. This was definitely a problem. The Lunar Princess was struggling to come up with a plan of attack, let alone one for defense. She tried sending out a few scouts, most had refused outright in the aftermath of the others being gleefully murdered for no apparent reason.

The ones that had been willing to go out, reported the oddest thing: the enemy was sleeping. Luna also struggled to wrap her mind around that. How could you cause so much damage, so much chaos, and then just go to sleep?! It was maddening to even try and consider, so she decided not to. Thankfully the scouts had been much too afraid to approach the sleeping beast, but they'd also confirmed something else. The enemy was in fact a pony. Which meant every foe save for Cozy Glow or Tempest Shadow was right out in terms of identity.

Luna had almost thought that it might have been Queen Chrysalis, but the scouts confirmed that there were no changeling markings or coloring. Flames aside, they were pretty sure the pony that was sleeping on the fountain had a white coat since it gleamed within the fire coating her very being. Even the wings were the color of freshly fallen snow, though they seemed to be topped in a form of armor. The metal had gleamed reddish gold in the light, so the scouts weren't sure if that was the true color, or just the way it seemed to appear because of the fire.

A part of Luna briefly wondered, but swiftly brushed those thoughts aside. There was just no way. She was ruminating over the map again, trying to decide how to best combat their equine enemy when Twilight Sparkle came galloping into the room again, skidding to a stop amidst a shower of sparks while panting for dear life. Princess Luna looked up, surprised.

"I know who it is!" Twilight cried out, breathing heavily. "I know who's destroying the city and everyone within!"