Everfree

(Before we did this to him, he called himself 'Torque',) Princess Celestia mused as she flew out to meet her brand-new foe, already irritated just thinking about him. He wasn't being the least bit cooperative about the role she and the other alicorn princesses gave him, despite the power and perks that came with it. (When he wished instead to be called 'Event Horizon' after his transformation, I'd hoped he had taken to it and would go about proving how right I was about the evil of his kind. But instead I get...)

(That which I'd discarded, restored...) Celestia flew over the castle she had abandoned in her flight away from memories of her battle with her sister. Princess Twilight had started the project of restoring Castle Everfree, but had also abandoned it in light of a castle of her own rising from the ground in place of the library she called home while residing in Ponyville. Like the youngest princess's castle, the prince's was a hybrid of crystal and stone. However, given that it was built under the direction of his will, the dark palace built of Everfree's ruins and power taken from King Sombra, and given to Event Horizon by the Alicorn Tetrarchy. Consequently, the dark crystal blended seamlessly with Everfree's Gothic architecture, at the cost of looking less natural than the other palaces with crystal elements.

(Those I failed to appreciate, given purpose...) Throughout the castle, Celestia could see a large portion of her own Royal Guard, their allegiance no longer pledged to her. An even greater margin of the Wonderbolts filled the sky, as a result of his having charmed Spitfire  before the Princesses gave him any real power. Both military factions now wore the new uniforms of their chosen regime. They were dark, stylish, and apparently allowed just enough variance to suit the quirks of individual ponies without losing the purpose of a uniform entirely to them.

Not that she could blame the defectors. When Celestia found herself alone after banishing Nightmare Moon to the Moon, the combined militaries of all three of the common pony races volunteered their services. However, with little in the way of tactical knowledge pertaining to large armies, a singular amount of personal power, and a very effective foreign policy, she failed to find a use for them. Over the course of just under a thousand years, the proud militaries had degenerated to mere decoration. In one season, Event Horizon had taken them well on their path beyond their former glory, using knowledge derived from being a member of a military from a species eternally at war. Given the two options, maintaining loyalty to Celestia seemed insane. She saw far fewer of them than had ever been assigned to the same

(The outcasts of my society, given homes... a path to redemption... and power...) Princess Celestia was not at all surprised to see Trixie Lulamoon, the legendary shame of the entertainment world, and her own failure of a student Sunset Shimmer. What they were doing, however, incited the princess to land and watch. The two magic mares were dueling, but that was hardly unexpected. They were both very arrogant and talented ponies, so the notion that the two of them meeting would lead to a clash was inevitable. However, it was their  demeanors that drew Celestia's attention. The princess could see by Trixie's stance and flattened ears that she had already acknowledged Sunset as the superior mage, perhaps as the result of a prior duel. However, rather than upset or angry, she looked determined. Sunset, on the other hoof, was neither laughing nor sneering at her opponent. Once Celestia managed to work out that Sunset was trying to encourage Trixie and teach her, she immediately looked for something, anything else to watch to distract her from her failure turning into a success without her.

She didn't have to look long. A mere moment was all it took for a yellow blur to draw Princess Celestia's attention to a pegasus pony racing through an impossibly hazardous obstacle course, within which the slightest mismovement had a high potential to result in permanent, debilitating injury or death. She was pursued hotly by several other pegasus ponies of the same apparent age, and watched over by Spitfire and a couple other ranking Wonderbolts officials. Spitfire had the same expression on her face that Celestia imagined she herself must have had while watching Sunset Shimmer.

(A functioning society, built of what I, my student, and her friends had treated as refuse.) At that, the princess decided it was time to move on before she was drawn in by the fascinating sight of the industrialized farm run by a rather distinctive pair of unicorn twins and the tantalizing aroma of whatever crop they were growing. It looked like some kind of hay, but there was something different about it. She shook her head and continued on, trying not to think of Chrysalis' new look -quite similar to her old one, minus the holes-, or of the burning hate she saw in Priceless Chinette's eyes. The both of them had nearly starved thanks in too large a part to disagreeing with Celestia. Granted, Chrysalis's problem was largely her own fault, but the mare behind the Grand Galloping Gala did not deserve the shame and self-loathing that came with finding out the princess deliberately sabotaged it.

It was seeing Event Horizon that irritated her the most, however. He waited exactly where he promised he would be, even though she was half an hour late thanks to her tour of his castle. The alicorn stallion sat at the edge of the Everfree forest, watching her with his face resting in its default expression, which Luna had shifted from disturbingly blank to glum during his transformation for reasons known only to Luna. As she landed, Celestia could see his just-visible muscles flex as he rose to greet her, a trait she'd preserved from his human form.

Looking him over, she wondered for an umpteenth time if the things the four princesses gave him: power, a new body, a home and a purpose here in Equestria; balanced fairly against those they stripped away: his original identity, the value of much of his knowledge, and the hope of ever returning to that rotten world he called home. Her eyes caught on that tuft of slightly overgrown fur Twilight had put at the high point of his chest, and Celestia found it annoyingly distracting. It probably felt so good against the nape of some lucky mare's neck when- No! No no no, she would not think about such things! Twilight would be the one to add a minor but riveting detail like that. She could see traits given by all four princesses in his body, and again found herself wondering how he felt about it, about looking in the mirror and seeing the face of a good-looking complete stranger of another species.

What irritated more than the guilty conundrum, however, was that he chose to obey her despite her clear desire that he do otherwise. Celestia did not want another subject, another pony to cave to her will and feed her ego. She wanted what she'd lost in Luna, though perhaps never had: a rival. She wanted somepony to tell her that she was wrong and be right. Somepony to point out her ignorance and how she might overcome it. Somepony who would compete with her and win, perhaps more often than not. Celestia wanted desperately to overcome the terrible stagnation that had been much of her existence for the past thousand years, and which she was threatened with an even greater extension of by Princess Twilight's successful and more thorough defeat of her old foes.

"Oh! Good afternoon, Princess!" he started, as though he were pleasantly surprised by her arrival, despite his having requested her presence personally and directly. It infuriated Celestia further that he seemed sincere, and might well have been. "It is later than I expected. I was beginning to wor-"

"Event Horizon!" she growled at him over his unnecessarily pleasant introduction. "I imbued in you all the Dark Magic we four Princesses could get our hooves on, and you do nothing with it! What is the meaning of this?" He reflexively backed away from her, despite having the capacity to defeat any two or perhaps even three of the Princesses, which only angered her further. How was somepony so weak-willed containing enough Dark Magic to drive Celestia herself into the depths of insanity?

"Dear Princess, while I'll admit that what I've done seems disproportionate to the power you've granted me. And um, I know at first it  seems that what I've done is unnecessary in light of said power, but I promise that I'm following your geas precisely as you wished." He said, moving as though to pass her, but stopping once she turns to follow him so they are standing side by side facing the new Castle Everfree.

"You... what? Just how exactly is building your own kingdom and bringing happiness and hope to ordinarily miserable ponies a work of evil?"

"Oh come on. Give yourself a little credit, Princess! You and I both know you can work this out yourself!" he replied cheerfully. Not maniacally. Not smugly. Cheerfully, and with a touch of condescension that was all it took to erect an impenetrable wall before the train of Celestia's burgeoning rage.

"Oh... my... you... you're..." Celestia started to cry when she realized what Horizon had done, and what he was setting himself up to do. All that power she'd given him, and it was still the brilliance he'd already had which he'd wielded to bring about the bloodless undoing she had requested that he try to make a play for. If Celestia didn't do something to repair her reputation soon, it was possible the citizens of Equestria might decide they didn't need her any more. Which was what the princess thought she wanted until she realized she was probably about to get it.

"Oh... whoa! Hey! No waterworks, please. You know I can't handle that." he said, drawing her attention from his plot and back to him.

(He was pretty broken by the world he'd been taken from, inside and out, wasn't he?) Princess Celestia thought, then wondered, (Why does he want so badly to go back? He spoke of living bereft of friends or family. What obligation draws him back to that wretched- wait, why is he so close now?)

"Besides," Event Horizon continued, reverting back to that hushed, half-mumbled manner of speaking he had when they first met. "Your subjects have a lot of well-deserved faith in you. You should try putting some in them. Also, you wanted this challenge to your authority, and you got it! Did I do a good job? Do you like it?"

Celestia would have been overcome by rage or despair if confusion hadn't beaten them both to the punch. Instead, she found herself wondering what Horizon's original purpose in summoning her specifically to this spot was. If he'd intended to attack her or rub his new glory in her face, he could have done a better job of it in his own throne room. He had to have a reason for this particular location though. He always had a practical reason for what he did. It was one of the points Luna made in favor of making him what he is today.

"You did fine. Never mind that, though. Why are we here?"

"Oh! Right! That. Well, you see... I actually have a request or two to make of you regarding this little forest right here." he said, and finally rage, borne of frustration, defeated the confusion and all else in Celestia's heart. She all but literally exploded.