“I met Tempest the other night.”
Celestia's eyes didn't veer from the board. “Did you now?”
Sunset looked slightly amused, “She doesn't play chess.”
Celestia slid her rook over a few spaces, “I didn't have the time to teach her.”
“She watched as Twilight and I played.”
“How was Twilight?”
Sunset shrugged, “Not bad, but you can tell she doesn't care much for it. Very competitive, though.”
“She's a lot better than she used to be.”
“So I've been told,” Sunset chuckled. She advanced a mage. “She's quite tall.”
“Twilight?”
“Tempest.”
“That was out of my control.”
“Sure it was,” Sunset rolled her eyes, “An otherwise normal pony just happens to grow nearly a full head taller than the general population.”
Celestia silently sipped her tea.
“You must have given her something in exchange for her horn,” continued Sunset, “Why not added height? Unless, you made her more powerful...” Her eyes widened, “She's an alicorn, isn't she?
“Why do you seem so intent on knowing?”
“Forgive me for wanting to know every piece that's in play.”
Celestia sighed, taking another sip of tea, “You're too much of a strategist for your own good. Just focus on your portion of the board.” She looked into her cup. “Is this the same tea you always bring?”
“Yes. Why?”
“It tastes a little different.”
Sunset hummed. “I must admit, she is an odd one—Tempest, I mean. No doubt, her time with the Storm King seems to have done a number on her. Who knows what horrors she has done in his service. I can't help but wonder how many foes she's fallen. How many may have been ponies. How many sacrifices she has performed for you.”
Celestia's voice deepened, “It is best for you to drop it, Sunset Shimmer.”
“I just hope what we received was worth more than the price.”
“You think I don't know the price of a life? Pony or otherwise? If blood was spilled, it was for the betterment of all. Those who may have died did so so their kin could live. Equestria is stronger because of it. Our borders are secure and buffers have been created. We have allied with our neighbors and dispelled our enemies.”
“Yes, you've done well building the fortress, but what of those within?”
Celestia was stupefied.
“That's your problem," Sunset explained, "You're too focused on external threats, playing games of 'what-if'. All this elaborate scheme to make alliances with our neighbors; to bring the Hippogriffs out of hiding. They were never our enemies, yet you treated them as if they were.”
“You must always be conscious of outside threats,” Celestia frowned.
“All well and good, but what about the inside? Your gaze is so far away you can't see what's going on within your own ranks.” A wry smile crossed her lips as she moved her rook to check Celestia's king, “What of Cozy Glow? How did she go unchecked?”
Celestia snarled, “I refuse to speak of that mistake.” She captured Sunset's rook.
Sunset leaned forward, an amused smirk on her face. “She's the reason you became secretive and selective as to who you told, isn't she? Still, it's a bit comforting to know I'm not the first to betray you.” She moved her mage forward. “Checkmate.”
Celestia frowned, “No, it isn't.”
“Oh,” Sunset pushed away from the table, “I believe it is. Tell me, Celestia, how many games have we been playing?”
Celestia's frown deepened, “What do you mean?”
Sunset playfully lilted, “Only that we've been playing several games these past few weeks. And I was wondering if you knew exactly how many we've been playing.”
Celestia's eyes widened as she began to comprehend, “What have you done?”
“Only what you have trained me to do.”
“Sunset!” Celestia roared.
Sunset smiled, “Why are you so upset? I'd thought you'd be proud of your work. I am everything you created me to be.”
“I created you,” Celestia's eyes narrowed, igniting her horn, “and I can also destroy you.”
“Not so fast,” Sunset chimed.
Celestia instantly felt a sharp pain in her horn. It felt as if a sudden block had been placed on her magic. She quickly disengaged. “What?” She reached up for her horn, but her hooves felt heavy. She looked to Sunset. Was Sunset experiencing the same? She studied her student's face. No, she seemed fine. If there was something in the tea... Celestia stopped—the tea! Had Sunset even touched her tea? She'd made herself a cup, but had she drunk any of it? Wide-eyed, she glanced at Sunset's cup. It was filled to the brim as it had been since the start of their game.
Come to think of it, had Sunset drunk any tea in the past weeks?
Her eyes locked with Sunset's. “What did you do to me?” She demanded.
“Hemlock,” Sunset said simply, “Surely, you've heard of it.” She walked to an open spot of the floor and stretched out her limbs. As Celestia watched, she noticed other things stretch as well. “I may be exactly like you in so many ways,” Sunset continued, “but having a profound weakness for tea is not one of them. Ha! You drank the whole pot without questioning!” She let out a moan, giving Celestia a knowing smile, “It feels good to stretch! ... Hm?” She flapped her wings, “You're wondering about these things? Yes, I've ascended. It's been quite a while now. Oddly, it was with Twilight's help.” She chuckled, “Maybe there is something to this 'friendship stuff' after all.”
A growl rumbled in Celestia's throat, “What is the meaning of this?”
Sunset shook herself off, “Well, if you've taught me anything, it's to strike before anyone can strike you. That is the way of war, is it not?
“Oh, you're asking why? Well, it's quite simple, really. I want what is rightfully mine.”
Celestia's gaze narrowed, “And what would that be?”
“The mirror world. After all the work I've done, and will do, it should be mine. You must be daft if you think I'm just going to hand it over to you once we're done. Twilight can keep Equestria. I'll have more power than you or she could ever imagine when I'm done. But, in order for that, I need Twilight alive and I need her as ruler of Equestria.”
“We've discussed this. That realm will be yours once we subdue it.”
“Sure,” Sunset rolled her eyes, “you'll give it to me just like you gave Equestria to Twilight. Suppose you did give me that world, what guarantee could I have that it was truly mine?”
Celestia bared her teeth, “Is my word worth nothing?”
Sunset shook her head, “That's the other thing. I can't wholly trust you. You're so willing to dispense with Twilight, I have to ask myself: how much longer before you turn on me as well?
“You know why Twilight must die.”
“Yes, and how can I be sure that you don't have similar plans for me? You've told me so much, but how much more are you still hiding? That's the thing about betrayal, isn't it? You see it around you, and you start wondering when it will be your turn.
“You know the funny part? Both Twilight and I would have died for you, if you'd only asked. But, you never ask. You're the grand master who sits over her board and orders where the pieces go. Well, this pawn just became queen, and she's decided that she's had enough! I've broken free and I'm going to free everpony else like me!”
“You don't know what you're doing,” Celestia protested, “You'll leave Equestria open to her enemies. You'll destroy everything we've built to protect!”
“I'll take my chances than live under your tyranny. Unlike my sisters, I know what it's like to live, to be free. I've learned so much; experienced so much. I was my own pony in that world. My life was finally my own. I can't go back, and I will not leave my sisters behind.”
Celestia huffed, “Cozy Glow wanted power. You want freedom. Both of you are fools.”
“I'd rather die a fool than a puppet.”
“But many will die!”
“And many more will live! Is that not how your equation works?”
A smile slowly crept across Celestia's face, though she was seething. “All the same, you will still die. Do you know why you were created? I needed ponies who would go out to dangerous places and do dangerous things. You, and those like you, were born to be expendable.”
Sunset took a step back. “So, now it all comes out. Our lives are worth nothing to you. That's how you can just throw Twilight away. How you can treat others like breeding stock. You care nothing for us.”
“I didn't say that.”
“Then what did you say?” Sunset spat.
“If I didn't care, why did I let Cozy Glow live? If she were worth nothing, I would have killed her the moment she turned. I may think less of you than other ponies, but I am not so quick to end your lives. You think it doesn't pain me to think of what I must do to Twilight?”
“If you cared for her at all, you would have found a way to let her live.”
“I tried. But, in the end, it would have been to a great detriment.”
“Then, you should have let the decision be her own!”
“Instead, you put me in her place,” Celestia sneered, “Ha! You really are no different than me! Okay, I suppose that is my own fault. But, what then? Sure, you kill me, but what will you do next? Tell Twilight the truth, I suppose?”
“No,” Sunset said softly, “At this point, that will only destroy her. I must now ensure that she never learns.”
“She only deserves as much," Celestia teased, "They all deserve to know.”
“If necessary, they will know, in their own time.”
“Even if it brings about their ruin? Not all have the strength of you.”
“With freedom comes ruin. But, together, we will be stronger.”
Sunset took Celestia in her aura and carried her to the bedroom where she tucked the former diarch into her bed.
“You know you won't get away with this,” Celestia growled.
“I'm pretty sure I already have. Murder is so rare in Equestria that we're so primitive in our investigation process. In fact, you'd be surprised how many murders do go unnoticed because the very possibility of it never crosses the mind.”
Celestia's eyes widened, “Don't tell me you've done tests in preparation for this!”
“No,” Sunset shook her head, “Just did some sleuthing. Don't know why you're so upset. Wasn't it you who wanted an assassination?”
"Luna would suspect something," Celestia said, forcefully. But, she quickly grew fearful when Sunset's expression didn't change.
"Then, we'll just see what she has to say when she gets back from Appleloosa." She returned to the living area and began clearing the coffee table.
Celestia listened as dishes were placed and washed in the sink. She listened to Sunset put each item away as she dried them. From her bed, Celestia had a direct view through her open door to the table. She watched as Sunset put the chess game away and return to the bedroom. Celestia tried to move her head, she tried to speak, but the poison had rendered her completely paralyzed. Helplessly, she watched as Sunset removed the magic blocker.
“There,” Sunset said, gently. She tenderly closed Celestia's eyes. “You just rest. It will all be over soon.”
Celestia listened to Sunset's hoofsteps as she walked back to the main area. She heard the hinges creak and the door latch click.
Outside, she could hear the rustling of Sunset messing with her saddlebag. She heard some hoofsteps and another door being opened and Sunset calling out.
“Goodbye, Celestia,” Sunset said, and closed the door.