Celestia had been in a good mood.
She grimaced, and worried at a familiar spot on the right side of her neck, just below her jaw.
Weddings were always joyous occasions. And while she rarely took the opportunity to officiate personally, this one was special.
This time, she'd be adding to her own family.
Finding Cadance at all had been a rare bright spot of true, unbridled joy in nearly a thousand years of loneliness. Not to say that she lacked for acquaintances, friends, or even treasured rivals. It was simply that, for most, she had to wear the mask. She had to be the princess first, and a pony second—if at all. There were a few individuals over the centuries who, by circumstance or temperament had given her the freedom to be her true self, and they too stood out as bright spots.
But Cadance was an alicorn.
The first in almost a thousand years. A possible companion in agelessness, someone who might join her in the march through the years. The way Luna should have. She could not be a replacement for Luna—nopony ever could be—but Celestia could be her teacher, her mentor. Like a daughter, or perhaps... a niece. That had nicely avoided most of the noble caterwauling about favoritism that adopting her directly would have caused. That it had conveniently allowed her to avoid the responsibility of being a mother was a slightly shameful little secret that she had kept to herself.
She did not think she was qualified for that particular job.
Things had not relented since then; she gained Cadance, lost one student, and gained another. And what a student Twilight Sparkle was! Possibly even more powerful and driven than Sunset had been, but deferential and humble, where Sunset had been dismissive and arrogant. And most of all...
...she had given Luna back to her.
The moon to her sun, the night to her day, the only pony that had grown up with her, understood her, and knew her. The only one who knew that she snored if she slept at just the right angle, knew that one of her wings was slightly crooked, and knew why she was deathly afraid of chickens—and was always willing to shoo them away for her.
Not without teasing her, of course. Oh, yes. The teasing, she had not missed.
And now, the mare that had given her the gift of a restored family—a gift beyond compare—would be joining her family, if only by relation to her brother. After today, Celestia would have the honor of calling Twilight Sparkle family.
But... that had been before Twilight's uncharacteristic, shocking outburst during the wedding rehearsal. She'd known that she and Shining Armor were close, but to be this jealous and protective? Especially with Cadance? The girls had always gotten along beautifully—what could have happened?
And now Twilight might not attend the wedding at all, on Shining Armor's insistence. Perhaps it had been too much to hope for. She had already been blessed by a truly miraculous amount of good luck in the last several decades alone. So what if she couldn't have everything she wanted? She had long ago resigned herself to a simple truth: some things were beyond her reach.
She looked into the mirror and again brushed a hoof along the right side of her neck, just below her jaw. There, marring her otherwise snow-white coat was a pitch-black mark—an image of a broken mask, cracked and pitted, with oddly-organic holes threaded throughout. She traced the spiky, pointed script beneath it that only she could read.
It can't be you. Don't! it read.
Her soul mark.
She could count the number of ponies who knew what it said with her hooves alone. At first, the secrecy had been out of a jealous sort of possessiveness. She had imagined those first words as a playful—but ultimately pleased—sort of rejection. But after the first century passed without a whisper of a soul mate, that possessiveness had turned to dread. What she had first imagined as playful felt more like a desperate plea every time she read the words. What sort of first encounter began with a soul mate rejecting her, then begging?
What sort of soul mate still lived after six hundred years, but remained unknown to her?
The latch to her bedchambers clicked quietly and she glanced at the door through the mirror. Deep blues and blacks, and a cadence of hooves that even a millennium apart hadn't erased from her memory.
"Luna," Celestia said, blinking. "You're up early. I didn't expect to see you for another hour at least."
Luna was one of the few ponies she had revealed the words of her soul mark to. Once things had settled down after her return, it was one of the very first questions she had asked Celestia.
Celestia hadn't been ready—it had been over two hundred years since the last pony who knew what her soul mark actually said had passed away.
But it hadn't been just some other pony. It was Luna.
In the end, she had told Luna everything. And Luna had listened, without reservation or judgment. And now...
Luna yawned and took a sip from the large mug of steaming coffee suspended in her aura. Celestia noted that it read best princess. "My sleep was marred by troubled dreams. When I awoke, I was informed of the events of the rehearsal. I suspected my presence was needed here more than abed. By the look on your face as I came in, I was right."
Celestia frowned. "You need your sleep. You don’t need to worry about me."
Luna rolled her eyes and threw herself onto Celestia's bed, rumpling the covers. Celestia's frown deepened. "Somepony must. For all that you are surrounded by maids and servants, few are willing to gainsay you."
"Luna, I'm fine."
Luna gave Celestia a flat look. "You were worrying at your mark again. You only do that when something is truly distressing you."
A glance down revealed that Celestia had indeed been unconsciously rubbing at her soul mark again. With a frustrated huff she lowered her hoof with a small stomp.
"What troublest thou, sister mine? Speak to me, Tia," Luna implored.
Celestia sighed and looked away, pacing a few steps before turning back. "You heard about the rehearsal, you said?"
Another sip of coffee. "Imagine that I haven't."
The pacing began in earnest. "It was Twilight. First, she was late to the rehearsal, which is already uncharacteristic. Then, when she does show up, she calls Cadance evil! It makes no sense. She's close to her brother, but she's never been protective of him like this. And against Cadance of all ponies—Twilight loves her!" Celestia exclaimed, gesturing wildly. "Twilight's mother once told me that Cadance was the only foalsitter they'd ever had that Twilight herself asked for. Getting Twilight to even remember another pony's name was an accomplishment back then! I just don't understand!" Celestia dragged a hoof through her mane roughly and stared at the floor as though it would yield answers.
Luna blinked slowly, then drained her mug of coffee. It took several noisy seconds that Celestia spent glaring. Finally, she finished and set the mug aside on Celestia's nightstand. "Would it be a fair assumption that you spoke harshly to young Twilight Sparkle upon your exit?"
Celestia's face twisted and she looked away. "Yes. I told her that she had a lot to think about. Which... might have been harsh, upon reflection. She overstepped, yes, but her brother had also just told her she was no longer welcome at his wedding."
"Mmm." Luna nodded, and was silent for a moment. "Do you trust Twilight Sparkle's judgment, sister?"
A sigh. "Usually, yes. But I fear that she's not being objective in this case."
Luna slid off the bed and moved to the room's expansive Prench doors, and stared out at the late afternoon sunlight. She turned to look at Celestia over her shoulder. "How well do you know Captain Shining Armor?"
Celestia blinked. "Reasonably well. He's been captain of the Royal Guard for several years now."
"Better than his sister?"
Celestia pursed her lips. "I take your point. No."
Luna nodded. "The wedding is not till the morrow. There is still time. Find your student, and speak with her. Seek to understand her point of view, and find reconciliation if you are able. We may be able to salvage this and find you your happy ending yet."
Celestia gave Luna an embarrassed smile. "How did you guess?"
Luna rolled her eyes. "You have always been a hopeless romantic. Besides, I confess to sharing your desire—I would be honored to have my savior as a glad member of our family as well. Now—" Luna gave a huge, jaw-cracking yawn—"I believe that it is time to see if the kitchen day staff have yet mastered the dark art of preparing breakfast past the hour of ten," Luna said, striding toward the door.
"Luna!" Celestia called. Luna turned and raised an eyebrow. "Would you... be there during the wedding itself? I know it's during the middle of your sleep cycle, but..." she trailed off hopefully.
Luna rolled her eyes, but wore a tiny smile. "If it will make you happy, yes. And I'm certain that our niece will be delighted as well. But I expect you to make excuses for me when I start snoring into my dinner at the reception."
"Thank you," Celestia said, smiling.
Luna gave her sister a negligent wave, and left, closing the door behind her.
Celestia let out a long, slow breath. All she had to do was find Twilight, and speak to her. Maybe get everypony—Twilight, Cadance, Shining Armor, and herself as mediator—together and talk things out. Luna was right—she could still salvage this.
Celestia stood at the altar, wearing her smile like a shield. She had been unable to find Twilight Sparkle yesterday and—more concerning—nopony had seen her since yesterday's rehearsal. As the morning wore on, a deep pit of dread had formed in her stomach, and nothing she did dispelled it.
Something was wrong.
But there was a royal wedding to attend to, and the kingdom was watching. Neither Shining Armor, nor Cadance, nor Twilight's friends seemed worried, so Celestia took her cues from them. But she had been unable to banish a nagging suspicion since her conversation with Luna the previous evening. She had been unable to speak with Cadance directly, but Celestia had begun to watch her more closely in the limited time they had together and...
...did she seem more curt than usual? No more than might be explained by pre-wedding jitters, or the stress of coordinating a complex social event. But that was a touch out of character for her, wasn't it? Cadance usually responded to stress by smiling and being as aggressively cheerful and outgoing as possible, then drowning her sorrows in cheap romance novels later. But getting married was a momentous event, and a central part of her domain as the Princess of Love. It wasn't impossible that she might behave a little strangely, given the circumstances.
Right?
Luna gave a little cough from where she was seated in the front row. Celestia snapped her head up just in time to see the doors opening to admit the three flower fillies and the bride herself. She glanced at Shining Armor to gauge his reaction. He was staring at Cadance with a stunned smile, and little exhausted crow's feet gathered around the corners of his eyes. Celestia gave a small internal grimace—maintaining the shield around the city had been taking its toll.
Cadance strutted down the aisle to the tune of a twelve-pony trumpet march, and favored Shining Armor with a brilliant grin as she arrived at the altar. He responded with a tired smile of his own and they both turned to Celestia. She pushed her anxiety down; she had a job to do.
"Mares and gentlecolts, we are gathered here today to witness the union of Princess Mi Amore Cadenza and Shining Armor..."
One unfortunate side effect of a millennium of rule was that giving speeches had long ago ceased to occupy her full attention. She gave the speech on autopilot and divided the rest of her attention to fretting. At best, Twilight was missing a pivotal event in the lives of two ponies who were very important to her. At worst...
Time for that later. The vows had been exchanged, and now there was one last part for her to play. "Princess Cadance and Shining Armor, it is my great pleasure to pronounce you—"
"STOP!"
Celestia cut herself off with a small gasp. She knew that voice.
Twilight.
And not far behind her, a second Cadance—this one bruised and disheveled, but with a look in her eye that Celestia recognized at once. She glanced at the Cadance resplendent in wedding finery, and her sense of dread returned, so strong that it turned her stomach. Now that she had both of them to compare, there was something off about this other Cadance.
Twilight had been right.
The impostor's words washed over Celestia, and before she could think to act, a pillar of green fire exploded upward from the false Cadance. She stumbled backward, turning her face away instinctively. When she turned back, the sight that greeted her was something out of a nightmare.
Pitch black chitin, fangs, ragged gossamer wings, and a wicked, curved horn. With features both equine and insectoid, Celestia listened in stunned horror as the monster outlined her plans for Equestria. Her horror turned to growing fury as the changeling queen revealed how she had suborned Shining Armor, and brought an invading force to bear against Canterlot.
"First, we take Canterlot!" the changeling queen crowed, flying into the air. "And then, all of Equestria!"
"No." Celestia stomped a single hoof against the floor. A curl of smoke rose from it, and she took a breath, mastering herself. "You won't."
The changeling queen whipped around to stare at her with wide eyes, then fluttered gracelessly to the ground as her flight faltered.
"You may have made it impossible for Shining Armor to perform his spell," Celestia continued, striding toward the changeling, who began to back away. "But now that you have so foolishly revealed your true self, I can protect my subjects," she lit her horn, "from you!"
The changeling queen continued to stare at her, wide-eyed, openmouthed. Her jaw worked silently for a moment as the magical corona wreathing Celestia's horn continued to grow. "It can't be you," she whispered. Then, seeming to return to herself, crossed her hooves over her face and lit her horn in response. "Don't!" she cried.
It felt like Celestia had taken a punch to the gut. Her horn guttered out and she staggered back, reeling. "W-what did you say?"
Almost without conscious thought, her eyes darted to the changeling queen's neck. There, in incongruous pure white, was a rising sun. Underneath it, in graceful curving script were the words No. You won't.
She had never seen writing like that before.
But she could read it.
This monstrous queen was her soul mate.
The world spun around her as she grappled with the implications. Her soul mate, the one pony—creature—in all the world with the closest connection to her was a love-sucking fiend. A creature that subsisted on what it could steal through deception and trickery. A monster that thought nothing of attacking another kingdom just because it had something she wanted. A ruler who called herself a queen, but called her subjects her "minions". Celestia could not think of any being she had met with whom she had less in common. They were even opposite colors!
Before her, the changeling queen slowly retreated, shaking her head all the while. Celestia could see her repeating the same word over and over and again to herself, like a mantra.
As the queen backed up further, her voice rose in volume, and Celestia was finally able to make out the word. "No. No. No, no, no," she muttered, growing steadily in volume. "No, no no no no no no! NO!" she screeched in a voice laced with power, and enough force to rival the Royal Canterlot Voice.
The queen's screech blew out the windows of the room, and Celestia staggered back, flashing a shield into existence above the crowd to protect them from falling glass. Eyes wild, the changeling queen lifted into the air, wings fluttering as she weaved to and fro, then wheeled about.
Celestia raised her head and forced herself to focus on the retreating queen. She reached out a hoof—for what, even she wasn't sure. "Wait!" she cried.
But her entreaty was ignored. With a second, even louder screech, the queen fled to the skies above Canterlot, and shattered Shining Armor's shield. The pressure wave forced Celestia back, and she staggered and fell to her knees. She turned her head back to the sky just in time to watch the queen's retreat. Smaller changelings swept into formation behind their queen, and within moments, they were nothing more than a collection of vanishing black dots against the horizon.
As the retreating army vanished into the distance, Celestia picked herself up off the floor, and carefully planted all four hooves, taking care to ensure that her stance was steady. She closed her eyes, took a deep breath, held it until it hurt, then let it out slowly.
Then she opened her eyes and put the mask on. She had a kingdom of scared ponies to reassure. It was her job to make them believe that everything was going to be okay.
Everything was going to be fine.