Umbra yawned as she slowly plodded through the hallways. It was dark and quiet, neither of which bothered her much. Her glowing eyes could pierce the gloom, and she just wanted to make use of the little filly's room, so chatting wasn't a high priority.
Now, funny thing there. In any modern setup, there'd be one right there, in her room. But the palace was over a thousand years old. It lacked modern luxuries like that. It wasn't perfect. So she proceeded through the darkness. The silence was not complete. Clip-clops! And not even her own.
A guard? Guards did not walk like that. They were so reliable. They walked at a nice steady pace from one point to another. You could set a clock by their clippy clops. Umbra smirked at that idea, playing a piano with a marching guard for a metronome.
These hoof steps were more... erratic, as if someone were dashing, but then stopping. Quiet, then another dash! Umbra perked an ear towards is, trying to figure it out despite being tired, and also full and in need of a good leak. She was too tired to immediately swerve off in search of the not-guard pony. But her curiosity demanded she at least note its presence.
The fact that it was down a hallway she was coming closer to didn't help. "Oh what?!" The pony came into view, only to dash past. They had a brown cape, or was that a cloak? The difference between the two jostled in Umbra's sleepy brain. By the time she was satisfied, the figure was gone, dashing right past her. "Huh..."
She responded with all due urgency. Umbra went to the bathroom and took care of that urgency. "Ah..." Properly drained of that, she was able to go back to bed without further interruptions. Sleep came for her quickly. Was that a shadow thing? If she wanted to sleep, she just... did. Boy, if she had a super power, that had to be it. Forget throwing around crystal blocks big enough to crush a person. Shadow powers? Pfft. She could go to sleep whenever she wanted to! Now that's a super power.
There was no time to worry about that! Friends were coming! Umbra walked along with a big smile on her face, fangs on display as she imagined the girls. "Nope." She shook her head. "Not gonna get any work done. I'm headed to the train station." And, her decree thus given, she spread her wings and soared out the nearest window without further delay.
"My little pony," she sang as she flew through the air. "I used to wonder what friendship could be." Was that the right line? She had no phone to try to quickly Google that up. So she had to just assume she had it right. "My little pony!" Not that she was even much of a fan. Her anemic knowledge of the land was proof enough of that. Any real fan would have laughed at her, right in the face. Jerk.
But, they say, seeing is believing. She landed into a trot that slowed to a walk, right on the platform of the train station. The station was warm! Well, as warm as the rest of the city, which was pretty warm compared to the frigid frozen waste that was beyond that. She trotted up to the ticket line, joining it. Other ponies glanced at her nervously. Not the kind of nervous that came with 'oh no, this scary shadow creature is upon us!'. Oh no, it was way more 'Oh my god, it's that famous person!'. Or pony. Yeah, they'd probably say pony. Umbra was not signing up for that.
"Hey." She reached the front of the line. "When is the train from Ponyville going to be here?"
The attendant peeked at a schedule and checked a pocketwatch. "Looks like ten minutes." He nodded with a satisfied noise. "You want to ride it? Five bits."
"Nah." She was already turning away. "I'm here to greet folks getting off of it." She parked on her haunches, peering down the tracks that would deliver her a nice big package of friendship! "Been too long!" She fidgeted with an excitement she couldn't entirely fight. When the train came into view, she squealed, which made her blush. She hadn't meant to sound that excited. But she was!
When the train slid to a halt, Umbra was greeting it with an eager clapping. Then the ponies came out. Her eyes jumped from one furry form to the next. So many, but where... There! A pink form she couldn't miss. "Pinkie!"
"Umbra!" returned Pinkie with equal zest. The two rushed together and began to circle. "Hey wow. You feel... Better." She leaned in, eyeing Umbra critically. "Why do I feel like I'm talking to the prettiest pony in the city?"
Umbra laughed at that, a deep and potentially menacing sound that fit her status of shadow pony. "How does that even work? I'm #2, but I won popular demand, so that's pretty great, right?"
"Right!" Pinkie bounced in agreement with that idea. "Congratulations! Can't wait to tell the others." She waved at where the other girls were departing the train.
Umbra and Pinkie returned to the others, who seemed just as happy to see Umbra. Rarity's eyes went up to Umbra's tiara. "I love it. You know, when I'm not working on dresses, jewelry is another little hobby of mine. We should compare notes. Darling, you seem radiant today. Things going well?"
"Yes," declared Umbra. One syllable, zero doubts. "My life is pretty good right now, and it just got better, because you're all here." She went in for a hug and wasn't denied, sharing one with Rarity, with a Pinkie joining in without being asked, not that she was unwanted. Umbra turned suddenly to Twilight. "Princess summit!"
"Princess summit," echoed Twilight with a lot more nervousness. "Which we don't get to attend, at least fully." She sighed out at that. "Doesn't it bother you?"
"A little?" Umbra shrugged softly. "I want to hear secret princess things. I have opinions on civil reform!" She struck an imperious stance. "But I guess that can wait." She returned to her usual standing, a big smile on her face. "I get to chat with my favorite nerd's nerdy sister, who I like a lot."
Twilight blinked softly, parsing that. "I am glad to hear you and Shiny are getting along." She smiled a bit lopsidedly. "It's hard to keep being the same kind of nervous with this... energy." She waved at Umbra and Pinkie. "I swear, it's like it just became an environment."
"Stereo?" offered Umbra. But that only got a confused look. "Never mind. Welcome! All of you. Let's head to the castle." She spread her wings, but didn't take off. Several of the ponies she was leading couldn't fly, so walking was the order of the day.
Rainbow casually landed on her back. "Hey. You practicing these?" She prodded a still spread wing.
"Yes." Umbra looked back over her shoulder at Rainbow as she walked. "Why didn't you tell me about preening?"
Rainbow sank to her haunches, still on Umbra's back. "Huh, oops." And that was all she offered on that front. "You figured it out?"
"Yeah." Umbra tilted to the side, causing Rainbow to take flight briefly before coming to the ground. "And I learned that pegasi can preen each other."
Rainbow blinked, cheeks going a dark red. "Woah! Hey, hold your horses there. That's for, um, very close pegasi." Her wings fidgeted with the thought. "I take care of my own wings, thanks."
Twilight advanced into the conversation. "Oh, communal grooming techniques? That has such a storied history. Why, pegasi history has been--"
Rainbow grunted softly. "There ya go, you set her off."
Twilight frowned. "I was not 'set off'. Excuse me for finding any interest in your history!"
"You're excused." Rainbow gently booped Twilight even as they walked. "Don't let it happen again."
Applejack snorted at the exchange. "Glad yer doin' alright, Umbra. We came ta support Twi here."
"Which I appreciate." Twilight moved around to get to Applejack's side. "Having my friends around is quite a... Thank you."
Umbra smiled coyly. "So... don't suppose you found any cool shadow spells you want to share, hm?"
Twilight burst into a little giggle. "I forgot how insatiable you are. Reminds me a little of me." She curled a hoof to her chin. "But let's save comparing spells until later. Now's not a good time for reading."
Applejack drew her hat down a little. "Ya know it's serious if Twilight don't got time fer readin'."
The group laughed, but accelerated all the same, making good time to the castle.
A large alicorn sat before Umbra, looking her over with an intensity that was somehow expressed without any specific threat. It was a force of personality perhaps? Umbra was meeting Celestia, and that she was the true queen of the land seemed impossible to deny. "Queen Umbra, I am told?"
Umbra darkened at that. "I've mostly dropped the queen part. It was the name that felt right, at the time, but I didn't know any better. I do now." She waved a hoof at Celestia, the big pony before her. "You're the queen here, not me."
Celestia smiled gently. "I am no queen. A queen is a tyrant, she must be. Most of my little ponies never hear my command, and that is the way I prefer it. Tell me, Umbra, were you queen, in all its meaning, what would you do?"
Umbra sat up, ears twitching. "Well, hm." She frowned with thought. "To be honest, the first thing I'd do is learn what I should do. I don't know this kingdom way at all good enough to give good ruling advice. The people in it seem happy. They have food and shelter. You have quality help." She pointed to where Cadance was eagerly greeting Twilight. "So I'd say you're going a pretty good job, from this angle, and I wouldn't rush to mess that up."
"How humble, for one that once called herself queen." Celestia leaned in, neck reaching what seemed like quite a distance. She was shaped more like a swan then a horse, in that way. "I have heard so much about you, little princess of darkness. That harmony has seen fit to..." She reached out a hoof, tapping at Umbra's left wing. "It's hard to argue with what's in front of us."
"Agreed!" squeaked out Umbra. Celestia seemed to be nice, but she was still... "You're a little, a lot... You're a lot to take in, ma'am."
"Celestia will do." Celestia leaned back upright. "We are both princesses. No need for formalities beyond that, between us. You care for my little ponies, so I have no reason to look unkindly on you, even if your presence does raise so many questions. Ah, did Cadance mention the mirror?"
Umbra jerked upright. "Mirror?"
"I will take responsibility for that." It was clear she had not been told of it. "Cadance mentioned your origin, which was just one more reason among many I had sent it. You see, certain mirrors, enchanted a certain way, allow us to peer into realities outside our own, to worlds that are ours, save for some small, or sometimes large, difference in their past that makes each one unique."
Umbra's eyes sparkled. "Multiverse mirrors?! Awesome!" she looked excited, rather than the confused or amazed that Celestia had been expecting. "You sent one here?"
"I did." Celestia nodded gently. "It leads to a world more widely separated than many. What if this world were filled with bipeds? With hands." She reached out a hoof that was very much not a hand. "Does that world sound familiar?"
Umbra's eyes widened as she sank back, reeling. "That mirror may lead back?" Part of her wanted to say 'home', but it wasn't home, not anymore. She was the shadow princess of the Crystal Empire. That was home! "Thanks, but I'm pretty happy here."