ARTIST’S NOTE:  
What would you do if you were made one of the most powerful people on the planet? Some would go out and start remaking the world as they saw fit. Others might use the chance to indulge in whatever depraved hedonistic wishes they might have.
 
Twilight had other ideas. She went to the restricted section of the Canterlot library.
 
The library had many levels of restriction, as is to be expected with the sort of knowledge it held. Some were reserved for advanced students in the School for Gifted Unicorns, others were allowed only to those individuals that had earned the trust of the princesses themselves. And then, there was THE Restricted Section, a place many students thought was only a rumor. It was a secret library forbidden to all but the princesses themselves, guarded with many of the same wards that had protected the Elements. It was a curious idea, to say the least. It held knowledge that shouldn’t be forgotten, yet shouldn’t be known to anyone else. Eldritch tomes, secret histories, and accounts of things too horrible for the weak-willed to know were locked away in those halls.
 
And now, Twilight had full access to all of them. The first chance she could get away from the coronation and celebration ceremonies, she did. For three straight days she had poured over them ceaselessly, not even coming out for food or sleep (a nice side benefit to her new form was that physical needs like them became far less pressing). She read the tomes on Tartuarus’s discovery and what it truly was; she poured over the history of the First Diamond Dog slaver empire, which included helpful guides for breaking the wills of different species, along with highly detailed diagrams for each; She read the atrocities of the Crystal War, and just how far the Empire had fallen in its glory - that the current “empire” was nothing more than a single city in the once continent-wide civilization.
 
But through all the horrors she read, there was one question she had. There was a figure that appeared in nearly every book. It had many different names - The White Flame, The Cleansing Light, the Night-Ender, The Death of Shadow, Demon of Light - But they all had the same basic description, and more importantly, were greatly feared by all, save its legions of soldiers. Pony soldiers.
 
Finally she had enough. If she wanted to find out, she’d have to start at the source. Or at least someone closer to the source than she was. She emerged from the library to the great surprise of the nightguard stationed outside it - she had been in there so long they had forgotten anyone was in there in the first place. With a quick apology she scurried off, looking for Luna. It wasn’t hard to find her, as her enormous figure and starlit mane made her stand out from any crowd. She was on one of her routine patrols of the palace grounds, her armor shining in the moonlight, making it look like she was glowing. She turned to Twilight as she half-ran to her fellow princess, giving her a curt, polite nod as she did so.
 
“Princess Twilight.” She greeted, in her usual formal manner.
 
Twilight returned a weak nod, before blurting out “Do you know who the Dawnbringer is?”
 
Luna tensed, her grip tightening on the hilt of her sword and her expression turning stone-faced - which was an achievement for her. Twilight could have sworn she saw her fur bristle slightly.
 
“Let us go somewhere private.” It was more of an order than a suggestion. Twilight was about to point out that there wasn’t so much as a sentry on the walls in this part of the castle, but knew there was no arguing with the night princess, and followed behind her long strides. Luna led them inside, passing through door after door until they came to what looked like an old storage room. It was full of antique chairs and tables - the sort that are too ugly to actually use, but are too expensive to just toss out. They each pulled a sheet off the overly-carved chairs, trying not to inhale the clouds of dust, and sat down. Luna looked as stiff as the chairs themselves, while Twilight tried to relax, leaning forward towards the blue alicorn. A cold silence filled the room, until Luna broke it.
 
“She did not tell you?”
 
Twilight turned her head, confused. “Who?”
 
“Celestia never told you, about us. About her.”
 
Twilight looked both more confused and interested, and Luna continued after a quiet sight.
 
“Twilight, when you look at Celestia, what do you see?”
 
That caught her off guard, and Twilight slunk back in her chair, pulling on her skirt nervously like a schoolfilly trying to answer a question on the chalkboard. Luna’s expression relaxed, the slightest ghost of a smile showing on her lips. “This is not a test, Twilight. I shall not judge you for this.” Twilight gulped, then thought about her former teacher. “Um, she’s… bright, and happy, and tall, and…” Twilight trailed off, and Luna nodded. “Have you ever seen her angry?”
 
“Only when she was fighting Chrysalis, and… w-well…” Even in the pale moonlight, Twilight’s blush was obvious “The doll incident, yes. I remember it well” Luna finished for her. “But have you ever felt threatened by her? Have you ever feared for your life around her?”
 
Twilight looked shocked, and a bit offended. “What? No! Of course not!” Threatened? By Celestia? She was the kindest, most patient and gentle pony-
 
As if reading Twilight’s mind, Luna held up a hand to stop her. “Twilight… Celestia and I are not ponies. Not in the same way as you are.” Now Twilight was absolutely bewildered. She struggled for words. “Not pon- what?” Again Luna held up a hand, and again Twilight was silenced. “Over the centuries, we have been soaked in magic. It has become part of who we are, what we are. How you or anyone else sees us depends on how they perceive us. Does that make sense?” Twilight’s expression clearly stated that it did not, and Luna continued. “You see my sister as a kind, gentle, motherly figure because that is what she is to you. But think about our enemies. Think about what she did to them. She had no love for them, no mercy, no compassion. She wanted nothing more than to see them destroyed, and she could do it. How do you think they saw her?”
 
Twilight thought back to the stories the history books told about great battles they fought and lost against the emerging kingdom of Equestria. They told of a Goliath figure shining like the sun, with eyes burning with hatred and death. It was wreathed in ethereal energies and fires that burned away anything or anyone who was caught in them. They told of whole companies of soldiers and monsters fleeing from secure positions at the slightest hint of her light, only to be cut to pieces by her blades or liquefied by her magic. She then thought of the pony who had happily stuffed her face with cake at every celebration, who had infinite patience with her when teaching her a new spell or magical theory. Who had once bought them matching dresses for a formal ball when she was a filly and had done the chicken dance with her in front of the Canterlot elite. She tried to merge the images together in her mind, trying to put them both in the same person, and couldn’t do it. She slumped in her chair, and Luna placed a comforting hand on her shoulder, sighing deeply.
 
“We all have moments in our pasts we are not proud of, Twilight, and my sister has more than her fair share. Please, I must ask you not to bring it up to her. She has made many, many sacrifices for this kingdom and its people, and has tried to leave the past in the past. She is Celestia, not the monster those books tell about. Let her stay that way.”
 
Luna stood up, opening the door but pausing in the doorway. “I cannot stop you, but I would not venture back into that library if I were you. Leave it locked away.”
 
Twilight didn’t need any persuasion for that.