You haven't seen this view in a while.
The train car rumbles beneath you, keeping a consistent pace along the winding tracks that will ultimately deliver you to Canterlot. You had grown quite accustomed to this ride some years ago, back before you could use magic and rely on teleportation circles to bring you back and forth between Canterlot and Ponyville. The seats are still just as uncomfortable (they, like most furniture, weren't designed with humans in mind), but you would be lying if you said you didn't miss the view. Being built into the side of a mountain, Canterlot provides many incredible vistas for looking out over the countryside, and the train ride is no different. The late spring foliage paints the rolling plains below in a beautiful pastel green, reminding you of the beauty that this world seems keen on showing off.
Looking around, there is a mare riding alone near the front of the car, dressed in a nice suit and reading what seems to be this morning's edition of the Foal Free Press. She is the only other creature present. You, meanwhile, are seated near the center of the car, doing your best to keep your distance from the other passengers. If the pattern so far keeps up, they won't be able to see, hear, or touch you anyway, but you would still rather play it safe seeing as you didn't actually pay for a ticket. Considering that your belongings disappeared and communicating with others in this state is extremely difficult, you figured that actually acquiring a ticket would have been a real hassle. So, you just kind of hopped on.
...You'll pay the nice stallion at the train station after this is resolved. Probably.
Eventually, the train begins to slow, signifying that you have arrived in the city. Stretching your back as best you can (the seat backs here are not nearly tall enough to accommodate you), you make your way to the newly opened car door, conveniently hopping out alongside the mare that was riding with you before the door closes again. Now that you're no longer violating any rules, you chuckle to yourself as you (quite literally) walk straight through the crowd of ponies waiting to board the train. Seeing as it's about midday, Tia is likely holding day court at the moment. This would normally make her hard to approach, but you're familiar enough with her schedule to know that after court, she'll be looking through whatever documents her aides have prepared for her for an hour. What everypony doesn't know is that it typically doesn't take her nearly that long to finish up, and she uses the rest of the hour to take a well-deserved break. Occasionally she spends it with you. You're a big fan of those afternoons.
Regardless, that will be your best chance to talk. At least until Luna takes over after sundown that is, but then you run the risk of her being tired and grouchy. If there is one thing you've learned about Tia, it's that she really, really enjoys her beauty sleep. With that "plan" in mind, you continue your trek to the castle, occasionally poking a high-brow noble pony here or there along the way. Disconcerting though the situation may be, at least you can find some fun in it here or there.
You reach the castle just moments after Tia's day court is supposed to end. Sure enough, you watch as the main gate is closed and a pair of older mares in fancy, expensive-looking clothing walk out. As per usual, a pair of guards are stationed at the gate, standing motionless and expressionless. You, being a regular at the castle, know these guards by name. Tia has given you clearance to enter and exit the castle whenever you want, but unfortunately, you're fairly certain neither of the guards will see you, let alone recognize you. That said, they can't really stop you from entering either.
You walk right up the gate and in a well-practiced motion you perform a short-range teleportation spell, delivering you safely on the other side of the gate. That said, you notice both guards let out a hushed gasp and snap their gaze to where you just stood. Both have a surprised, yet determined look on their face. Oh, right. If your magic works, then they would have been able to see that, and teleportation does produce a quick flash of light. The pair look at each other, seemingly recognizing that something just happened, and you quickly dart inside to hopefully avoid any potential conflict.
You make your way through the grand marble halls of the castle. The fact that a massive fantasy castle like this really exists never ceases to amaze you, let alone the fact that you're allowed inside. Unfortunately, the currently barren corridors are a bit creepier than usual. Typically your jaunts through the castle are accompanied by the echoes of your footsteps on the well-polished floors, but now... there is silence. There is the occasional servant or guard to break the silence, but for the most part, you have to do your best to stop yourself from getting creeped out.
Finally, you find yourself standing before a grand set of double doors, golden in color with an intricate design from top to bottom. You know these doors to be the entrance to the throne room, where Tia is most likely either signing important legal documents or taking a well-earned break. Just in case, you grab the handles and attempt to open the doors. To no one's surprise, nothing happens. You take a deep breath and gather yourself as a familiar sense of dread fills your being. Once more you perform a teleportation spell, landing you squarely on the other side of the door.
Looking around, the throne room is as grand and beautiful as ever. Of course you have the throne itself, upon which sits Tia in all her glory, silently reading over a long piece of parchment. A small stack of similar-looking parchment rests beside her, waiting to be examined. The walls are adorned with the castle's iconic stained glass windows depicting Equestria's many stories and victories over its enemies, the glass itself filling the room with natural light of all sorts of colors. Lavender, delicately placed by Luna the night prior, rests in fancy-looking planters in-between each window, giving the room a gentle, pleasant scent. You slowly begin walking towards the throne, your attention split between your lovely fiancé and the room itself. Something is... off. With both things.
Tia herself seems to be as composed as she usually is, but you can't help but feel concerned when you look at her. It is a feeling you haven't felt in several years, and a feeling you had hoped both of you left behind. If anyone else were to see her, they would think she is as fit and energetic as she always is, but you, with your plentiful knowledge on the way Princess Celestia functions, can see it clear as day: She is tired. The subtle ways her eyes move a bit slower than normal, the way her lips are curled back just a bit farther, the way her snow-white brow is just the tiniest bit furrowed. But she isn't the only thing strange. You stop your approach and give the room a good, long look before realizing what is out of place.
The windows, numerous though they may be, are in slightly different positions. While they begin the same, the more recent windows all seem to be shifted one spot over from what you are used to seeing, as though a window had been removed and all of the others had to be adjusted accordingly. And sure enough, after digging through your memory of this room, you realize that one window is indeed gone.
The window dedicated to the defeat of Shadowmere. The only window that depicted you.
...No. You don't need to get needlessly speculative again. Your house, your business, pretty much everything you ever did is gone. And if your hunch is correct, Tia's apparent fatigue is likely related as well. It doesn't matter what caused all of this. All you know is that you have to fix it. Filled with a renewed determination, you turn to face your wife-to-be once more.
"...Tia? Can you hear me?"
To your disappointment, she doesn't respond. It seems you'll have to do this the hard way. Looking around, you notice that Tia does have some blank pieces of parchment placed nearby. Deciding that you should first get her attention, you gently cast a spell to lift a piece from the top of the pile and slowly float it into the air between the two of you. At last, her attention is brought away from her work as she looks quizzically at the mysterious piece of floating parchment. You delicately have it flutter around in the air in a way that is intentionally unnatural looking. Tia's face hardens as she seemingly takes a more defensive stance, now aware of another presence in the room with her. Feeling that now is as good a time as any, you levitate the quill that she was just using, still wet with ink, towards the parchment and begin writing. You explain who you are and the situation going on, trying your best to describe what has changed and noting that it seems as though you've disappeared from reality. You finish the note by asking her if she remembers you, the human that she holds so dear, and you slowly float the note towards her until she takes hold of it with her own magic.
Her attention seems split between the note and the room around her. You surmise that she is (justifiably) cautious of whatever presence has made itself known to her. As she reads, her face seems awfully familiar to Twilight's when you tried this with her. You feel a weight in your chest as you prepare yourself for the worst. Eventually, she finally speaks up, her voice slow and methodical.
"...I am sorry to say that I can confirm your fears. I do not recognize your name, nor do I remember any of these events that you speak of. That said, you are surely aware that I cannot take this information at face value, yes? Whatever and wherever you are, you came into the throne room of one of the largest nations in the world and approached me, said nation's ruler. I imagine you can understand the position that I am in receiving a correspondence such as this."
You can't help but let out a sigh, your gaze finding its way to the floor. The worst-case scenario seems to have passed. Not only have you not obtained any answers, but the pony you care about most in this world, the love of your life, doesn't even remember you. You were right.
You really don't exist anymore, do you?
"But." Tia's voice reaches your ears once more, and there is little you can do now but listen to her. "Even in spite of knowing these things, you came regardless. As such, perhaps you are telling the truth. Or maybe you're just desperate. Or... possibly both. How can I know?"
Seeing an opportunity and not wanting to waste Tia's apparent trust in this invisible stranger, you grab another piece of parchment and begin writing once more. You talk about all of the time the two of you spent together, making sure to go in-depth on the details that a "stranger" couldn't possibly know. You talk about her fear of losing Luna, you bring up the issues she faces when dealing with specific nobles, you mention that spot right behind her left ear that she really likes to have scratched. You list her favorite foods, her favorite smells, her favorite places to visit around Canterlot while fraternizing with high society. You mention all of the things that made her fatigued way back when you first started having tea with her, from her responsibility of watching over Twilight to her reservations about the First's role in her life. Finally, possibly losing track of the point of your note, you being listing all of the reasons why you fell in love with her in the first place and recalling many anecdotes from your time together, like Nightmare Night and the Grand Galloping Gala. Whether it is out of a sense of nostalgia or the stress of this strange situation finally catching up to you, you feel tears begin to fall from your face, falling unceremoniously through the parchment and hitting the floor without making a sound. With no more room to write, you pass the note to Celestia for her to read once more.
The silence in the room is deafening as she carefully reads every word you wrote. As her eyes scan across the page, you can see her expression soften ever so slightly. It seems that your words caught her off guard.
"...I must say, this certainly does seem to help your case." She closes her eyes, which is appropriate seeing as she can't see the person she is conversing with. "In my many years, I have never had a romantic partner. But I cannot imagine anycreature being able to know all of this otherwise. Not even my dear sister is aware of some of this." She lets out a troubled sigh before continuing. "This is extremely unorthodox, but against my better judgement, I promise to do what I can. That said..." she places the parchment back down again at her side and looks around the room expectantly. "Let us perform a few tests. It seems that you can use telekinesis just fine, and the fact that you made it in here at all implies to me that you can teleport. As such, it seems that despite everything, you can still use magic. Let's see to what extent."
For the next few minutes you performed a variety of spells, including an illumination spell and a magical shield. After a while you explained in another note how you all discovered that your magic is strange, giving you access to spells that most unicorns cannot replicate such as your vines. You also mention your horn and wings, bringing them out as best you can. Judging by Tia's look when you did so, she can see them in spite of not being able to see you. She mumbled to herself a number of times throughout the process before settling back down again, apparently having reached a conclusion. Unfortunately, her expression seems uncharacteristically grim. You feel a weight in your chest as you listen carefully for her next words.
"Putting together what you have told me and what I have seen, it would seem that your initial fears of 'not existing' are fairly accurate. At least, to an extent." She seems to be growing increasingly uncomfortable as she continues. "We can make the reasonable assumption that this can only be the work of some malicious spell. That said, this assumption comes with two problems. First, why did whatever spell that caused this fail to prevent you from using magic? Second, what kind of creature is capable of casting a spell such as this?"
You hadn't thought about that. Is this outside the scope of an alicorn? Seemingly expecting you to be pondering exactly that, Tia responds despite hearing nothing.
"It would take all four of us alicorns to cast a spell of this scale, even on one entity. To banish a creature, or to... do worse would easily be within our power. But this takes a significantly larger amount of magic. And to what end? What good does this do?" Tia pauses for a long moment before finishing her thought. "...All known magic in the world operates the same way. While different creatures can manipulate it in vastly differing ways, it is ultimately the same magic. It is all part of the Cycle." Okay, that's a new one. The Cycle? You feel like you've heard that somewhere before, but you can't quite place it. "That is, except yours. Whoever or whatever you claim to be, there can be no doubt that your magic is unlike anything I've ever seen. And the fact that you can even begin to approach the capabilities of an alicorn is completely unheard of. It... may not be out of the question to say that you exist outside of the Cycle, that your magic differs from anything we've ever seen. That would at least explain why your magic still works."
Okay, so... what does that really mean for you? Your human magic is different from anything in Equestria. So what? To some extent, you already knew that.
"Putting these facts together, it would seem that there is a conclusion that we can naturally draw..." Tia seems almost ill as she continues her line of thought. "Who, or what, has magic so powerful that it could erase a creature from existence? It would have to be a creature that operates using Equestrian magic, and that would stand to gain from the spell itself. There are only two benefits that I can think of for using that spell as opposed to 'getting rid of you' the easy way. Either they want you to suffer, or they want to see what the world would be without you in it. I have a hunch it may be a bit of both." You catch your breath as she finally finishes her train of thought. "If we consider all of these to be the facts, it would seem that our perpetrator... has to be the First."
You feel your blood run cold. The First. The only deity in Equestria. The being responsible for Celestia and Luna becoming alicorns, and for allowing them to make Cadence and Twilight alicorns as well. The being that is apparently the reason why Equestria has magic in the first place, and the being that has caused much anxiety for Celestia in the past. Thinking back, you found a copy of "The Rise of the Two Sisters" in the old library in Zephyr Heights when you got sent into the future. It was essentially a bible that explained how the First was made up of all of the magic in existence, but gave up her physical form to bestow the world with magic. She gave Tia and Luna their alicorn magic to defeat Discord, and as such, the book discredits the sisters themselves in favor of describing them as little more than extensions of the First herself. Both out of some innate dread on the topic and at the behest of Celestia, you never looked too far into the First nor the religion surrounding her. Either way, you know this: You aren't a fan of anything that upsets Tia, deity or otherwise.
"...I apologize, but I must be getting back to my work." You notice Tia picking up the legal documents where she left off, but she is doing a terrible job of hiding her fear. Why does this have her so spooked? "I will speak no more of this. The rest is up to you. Good luck, my little human. I ask that you now leave my throne room."
This isn't the first time she has done this. Apart from voicing her general anxiety about whether doing what the First asks is the right thing or not, she has always been quick to change the subject whenever the First is brought up. You think you're beginning to understand why.
Not wanting to anger her, you teleport back out of the room, with many different thoughts flowing through your head. You trust Tia with your life, so you have little doubt that the conclusion she came to is the correct one. If only it wasn't so troubling.
You take a few moments to breathe, leaning against the marble wall in the silent castle corridor. If she is right, it would seem that the First has it out for you for some reason. What did you do to anger a goddess? What can you possibly do about it?!
No. You can't ask questions like that. There IS something you can do about it. You've sworn time and time again to protect Celestia in any way that you can. If your absence is causing her even the least bit of stress, you HAVE to return to her, no matter what. It doesn't matter if it's some rogue magic, an alicorn, or even a goddess. You've found a place to belong. You've found creatures that you love and that love you back. No matter what stands in your way, you will fight for them. You will fight for you.
You deserve to exist, and you're going to prove it.