Changeling. Even the name varies.

A pony would have you believe that a 'changeling' steals the reflection of those who spend too long preening in front of a mirror. A griffon holds that the 'cuckoons' sneak their young into the nests of unwary and inattentive parents, pushing the host's hatchlings out and leaving the 'cuckoon' child to be raised as 'normal' within the Clan. The dragons thinks the 'Fey' attach themselves to the their flights during the great migrations, and hold competitions to prove they're 'real' dragons in an attempt to weed us out.

Are they true? A little bit of truth mixed with a lot of misunderstanding.

A 'changeling' does not have a true form, or at least not one that our prey has ever seen. When we hunt dragons, it takes on the look of a dragon. When we hunt ponies, it resembles ponies. We hold no shape, we hold no substance; ever detached from a singular homeland, we bury our roots within the urban sprawls of the other races. There is only ever the Swarm and the hunt - unless you are a Queen.

A Queen is not part of the Swarm, in much the same way that no monarch is ever their own subject. Most changelings are males, Drones; born to protect the Queen and help in subjugating a herd. A Queen feeds off their collected adulation, protecting the Swarm as she is in turn protected. In time, she produces more Drones and, of course, more Queens.

It is difficult to tell if a town is infected from the outside, for in all aspects we strive to make it as complete an illusion as possible. An infected town is filled with denizens who laugh, work and play as if everything was normal. They gather in groups around bars and social areas; they sweat out in the fields and construction yards; they celebrate birthdays and royal anniversaries. Even in my birthplace we once had Celestia herself attend the Summer Sun Celebration, and she was none the wiser. A hive-town is nearly indistinguishable from uninfected one.

But, there are differences. Of course there are: if there were no differences, then why, exactly, would we be considered an 'infection' or a 'threat'? We are, after all, the reason why there are so many ghost-towns throughout Equestria and the world at large. In the end, the griffons were the most right.

An infected settlement has no children. How could it, when every husband, wife and lover is a changeling in disguise? How could it when the energies and substances needed to make a child are syphoned away into producing more and more of the swarm? In the end, for all our love, we never make its ultimate expression. Instead, we make the closest reflection we can: Queens.

A Queen holds a strange relationship with her parent swarm, for in the end they birthed us and, to a certain extent, own us. A town or village will not often last the length of one Queen's life, and so her children are sent out to 'seed' nearby settlements. We hunt for zones ripe with potential for the Swarm to occupy, disguising ourselves as figures of power and latching ourselves onto those of greater power (males only. There's a reason all of Equestria's highest powers are female.) If all else fails, we meld the memories of those around us, shifting suddenly into existence as if from nowhere - fortunately, I have never had to do this.

If our mother does not call on us, then our relationship with the settlement, and our chosen 'host', changes. For in the early stages, our relationship is more symbiotic than parasitic, and we truly 'love' our host. How could we not? He is our only form of sustenance; the single drip of food on which we fast whilst waiting for the call. The prop on which we lean and, ultimately, the source for our own Swarm should no call come. A female cannot reproduce alone, after all.

But usually, the call is sent flickering out along invisible leylines and we get ready for our mother's arrival. A call which says “The Swarm is coming. Prepare the herd.”

*****

I can not say I wasn't expecting it. There had been talk of a potential threat for days, and even though it is in our nature to be subtle, the prey grows ever smarter. I had successfully nestled myself into the royal Equestrian household - by no means an easy feat - and so was well placed to hear about the various goings on. A Swarm had been sighted near my birthplace of Manehattan; a whole suburb apparently vanishing into dereliction as my brethren had taken off into the sky. In all likelihood, my mother was on the move.

This in itself did not concern me much; though I was, of course, concerned. It had not been that many years since I myself was birthed, and even then the suburb had been slowly dying; its residents growing older and older as more and more of the swarm was forced underground or into self-habitation (typically, this meant several identical copies of ponies almost living in each others' backyards. Drones do not tend to be intelligent, after all.)

What concerned me was the reports of residents claiming to have 'woken up, as if from a dream'. Of frightened ponies asking for missing loved ones; of ponies mentioned 'black magic' and 'imposters'. For beings as ancient as the two princesses, this would undoubtedly lead to thoughts of 'changelings', and security as a whole would tighten. My position may have been compromised.

As well as that, what was mother thinking? It is not in our nature to leave livestock behind: every last drop should be harvested before the swarm moves on, to reduce suspicion if nothing else, and to stop our secrets from leaking out. The herd had been forewarned. Worse, she had decided to attempt to take the seat of Equestria's power from under the nose of Celestia and Luna themselves. Even as a Queen gorged on generation after generation of love, mother did not have that kind of power. I had thought picking Canterlot would make it certain that I would not be called upon. It would appear I was wrong.

But I had been selected, and even if I was only a few weeks away from my marriage (and a honeymoon that we would mysteriously vanish from), the Herd would be prepared. I would, of course, do my best for mother, which meant dealing with what she may have overlooked. Equestria has more powers in it than just the Princesses nowadays, as Discord's short release had more than demonstrated. To start off with, he would have to be contained, so that the Swarm would have only one threat to deal with. And then there was the matter of those who had imprisoned him... how to get them into one place at one time... Ah yes. The Wedding. I went to speak to Celestia.

*****

A pink barrier stretches across the sky, rippling in waves and patterns as the summer's breezes thrust small motes of dust and ferried leaves into it, the refuge from their airy passage into Canterlot sliding down the barrier's sides like a waterfall of trash. I'll admit: I am impressed. Conjuring up such a shield requires a grasp of magic beyond the ordinary unicorns. We would have made the strongest Swarm together.

Shinning Armor, my love and soon-to-be Husband is standing next to me, going on and on about some “Twilight Sparkle”, a sibling of his who should be arriving sometime soon. Apparently, she is one of the Elements that I requested, and my love, who had apparently forgotten to invite her himself, thinks that I invited her for his sake. I am happy to let him think this, as I am now firmly within his 'good books' – was there ever any doubt – and it makes preparing that much easier. That much more organic.

I lean my head against him; my nuzzle cutting him off mid-sentence. One of the guards gives a hoot, the originator hidden with a swiftly grinning line of troops, and, for a moment, my Husband seems replaced himself with a glowing-ember statue. Of course, he responds by barking out orders, smiling sheepishly at me and then stomping off after his retreating guards. I beam back widely as he turns once, twice, three times to look back over his shoulder. The devotion is touching. I will miss it.

Of course, there is a way round the barrier; a way he won't have thought off. It always pays to make sure you have an escape route in place for a hasty retreat if discovered, and even more so when attempting to sneak past the very rulers of the race you prey on. I would not have dreamed of infecting Canterlot had I not come across rumours of a 'abandoned crystal cave' beneath it; caves that, apparently, were forgotten and mainly thought to be just an old mares' tale.

As far as I could tell, old mares have been given a bad reputation.

*****

There are not many abandoned buildings within Canterlot. As a forefront of Equestria's power and might, the city naturally buzzed with far more activity than most places, and so naturally, most building were in use. Even the one I was currently in in no way appeared abandoned; any passers-by would think it a cherished household estate; any thieves breaking in would think the family was merely on vacation. The walls on the outside were polished to perfection. A slow stream of butlers and servants entering and leaving through the servants' entrance making it appear active. The indoor sofas and settees had been squashed down to give them that 'lived in' look. In fact, if I'd ever grown tired of the castle, I could have moved in here with no real fuss and changed it from unoccupied to infected.

Mother would be arriving soon: of that I had little doubt. The message had been sent not long ago, travelling across those magical passageways that linked a Queen into her immediate family. The Servants had been dismissed; the basement readied for her arrival. I was certain this house would serve as ground zero for our expansion: the swarm creeping out and infecting over-gilded mansion after over-the-top castle until we held enough power to challenge the princesses. Or die in the attempt. Either way, mother was being overly ambitious. I could only hope that she would not consider me too important a tool and that I might, somehow, escape without myself dying. Not that I would not give myself gladly, of course, but still: I did not want to die. Not on something as futile as this.

Green light splashes itself across the walls in a whirlwind of emerald aurora. Slowly, out of the flames, a figure spontaneously reveals itself. I bow low in reverence.

“Mother,” I say, and lift up my head and blink in surprise. It is not mother, but I still recognise her, though when last I saw her she was what ponies would call a foal and griffons would call an egg. A changeling larvae, appearing as a twist of shadows dancing in the air. “Sister?”

“Queen,” she replies, her eyes gazing manically into mine. “I speak for the swarm, the swarm from which we both were born. Mother has died, and now I rule. Canterlot shall be our new home.”

I blink again, my mind already working over what must have happened. Mother had died prematurely; nothing wrong with that, in many way it was to be both expected and, in a small way, celebrated. But it was not meant to happen when another Queen was present; was not meant to occur when a Queen was coming into her own and ready to leave the hive. All that attention, all those Drones filled to the brim with energy and love just looking for an outlet; a way to do what they were meant to do, and transfer energy out onto a Queen. And with mother dead, they'd done the next best thing.

'It had, of course,' I noted, with an almost detached air, as if I was reviewing all this for someone to read, “Driven her completely mad.”

All of it now made sense: the lack of coherent strategy, the plan to attack Canterlot itself, Celestia and Luna only vaguely factored in, the leaving behind of usable livestock. Every damn action screamed inexperience and the directions of something drunk with too much power.

“This is to be out main holding?” she asked, floating out of the basement and out in the house proper, her form a ghastly imitation of a pony. Warily, I followed. “It is far too drab to be our main holdings, but we suppose it will do for now.” She sniffed, eyes dancing in a kaleidoscope of merrily mad circles. “These 'other powers' you made mention of... have they arrived?”

“Yes,” I reply. “I spoke to one of the bearers not long before I arrived. The sibling of my host.”

“Good,” she smiled widely, revealing teeth that ought not to be revealed. “Your host, he is the one maintaining the barrier is he not?” I nod. “Good... then my plan will still work.”

“Plan? I was not informed of any plan whilst I was making preper-”

“Of course there is a plan!” she snaps, and I back off, ill at ease. Even though she is many years younger than I am, she has the strength of an entire swarm feeding into her. I have just one colt. This is not a fight I would win, if pressed. “The plan is simple enough, though effective. I take complete control of your host, draining him of all his power. The Barrier will fall, and the swarm can come through.”

“You... you mean to attack all at once.” Not mad with power: insane with it, inexperience battling it out with twisted logic to produce something as half baked as this. “You do not even want to subjugate the Royal Guard first?”

“No need! We shall wipe them all out!” I needed to get out of here, fast. “Ours shall be a glorious victory, enough to provide my starving Swarm with a feast to last across the generations! We shall cover all of Equestria in our loving shadow!” Whatever happened, nopony was going to be forgetting this. Equestria would not be safe for several lifetimes for any changeling. I begin to dimly wonder whether the dragon migration was still ongoing or if I could make it to the griffon kingdoms on what love I had.

“What is your form known by?” she suddenly asked, catching me so completely off guard that instead of the name 'Cadance' which most ponies knew me by, I said-

“Princess Mi Amore Cadenza.”

“Good. A name truly fitting for Queen Chrysalis,” she said, and whilst I was busy thinking 'Oh mother: she gave herself a name!' her form melted into the one I was currently wearing.

For the first time, I think I truly empathised with the prey. Seeing your appearance (for I had worn 'Cadance' so long that it more than felt like my own) reflected back at you is disturbed me on levels I did not know I had. Exactly like a mirror had suddenly sprung up between us, except my reflection was the one smiling and walking off without me and I was the one forced to mimic it.

“Stay here,” she commanded, not even looking back as she strode towards the door. “Do not be seen; do not act. Stay hidden until I call for you.” She left.

For the longest time, I was frozen; unable to move. This was not how things were meant to happen; this was not how things were meant to be. Mother was meant to give the call, and I was to assist to the best of my ability. My sister was not meant to call, and even though I had now been given the opportunity I had been longing for moments ago, I did not want to take it.

In all essence, my sister was nothing more than a rival Queen who had moved into my patch and taken over, and there was nothing I could do about. She was stronger than me. She was already out in the open, wearing my form and knowing my name. I doubted she would even act with any subtlety whilst playing a part I had perfected over many, many years.

She would not be the first Queen to try and muscle in on another Queen's territory, nor would she be the last. The difference here was that the encroaching Queen was usually the weakest one, the other having at least one food source, and they had not usually been invited directly into another's home.

I could not best her by strength, but, perhaps, I did not need too. She would not know how to act the part of Cadance: she had no experience, after all. My love's sibling had seemed to recognise me, having performed some ritual that had doubtlessly once held meaning to the real Cadance almost immediately upon meeting me. She, surely, would suspect something, particularly if I were to help nudge her along a little. And then what would ' Chrysalis' do? Send her somewhere safe to be dealt with later...

No, I could not win with strength; I would have to be subtle. But then again, we are creatures of subtlety.

*****

The cave walls glimmered softly as I teleported into one of the natural caverns beneath Canterlot, my hooves scuffing the ground up into floating clumps of dust around my legs. It took more out of me than I'd have liked: she must have already reached Shinning Armor and severed my connection with him. I feel weak, weaker than I have in years. I had forgotten how much I needed him.

I look down at myself and frown. My appearance simply won't do; Twilight will expect Cadance to have been down here for months but my coat looks like it's just come out of a spa. I concentrate, my form rippling in the air like the surface of a lake caught in a storm. The outer surface shrinks in a little, as if hugging me for warmth, and I take on a starved appearance. Cuts and bruise raise up along my legs and flank, the hair covering them growing wild and untrimmed. Finally, my mane; I let it flop out everywhere, the threads hanging down in a tattered collection of loose fibres that only just cover up my now tarnished and muddied accessories. I let out a sigh I didn't know I was holding in, my legs caving way as I flop to the ground. My store of energy is nearly exhausted. I miss my love more than I can say.

I take a quick look around before realising I'm lying with my back facing towards the sealed-off cave where she'll most likely send Twilight. She is drawing off my memories of the place, sent along with other thoughts of 'preparation' before, and if I was imprisoning somepony down here, this cave is where I'd do it. Of course, I'd never even think of trying to trap Twilight down here. It probably won't occur to her how foolish it is to put a magically talented unicorn into a cave mined by unicorns.

*****

My sister looks shocked as I step out from behind Twilight, as she has every right to. As far as she's concerned, after all, I should not be here. I'm ruining everything.

“It's all part of the plan,” I send to her, my lips saying something meaningless for the ponies around us to hear. “Just play along. I've got this covered.”

“What are you doing? Why are you doing this?” she sends back furiously, but she keeps up appearances. Good. If I can fool her just long enough...

I respond with something clever, my words matching hers as a silent battle of thoughts plays out, layered on top of a second conversation relayed for all to hear. I call her a changeling, she reveals herself, Celestia is defeated, the elements leave and it rapidly becomes clear that I need a good reason for being here, fast. She is not going to loose as I expected her to; if anything, against all the odds, she's winning. Now there's only three of us: me, her and a small, purple dragon in a tuxedo. He looks ridiculous.

“Why?” she sends, her fury lashing against me as my feet are firmly fastened to the floor. I think fast.

“The Elements. If they win, and you are defeated, I can still overthrow them later in this form. Help you back. Even if you loose, you win. The perfect plan.” Amazingly, she buys it.

“Yes... yes, of course... even if I loose, I win.” She cackles in reality, her laugh startling the dragon. I do my best to look surprised too. “Nothing can stop me!”

And then the elements arrive, bound and helpless, and it quickly becomes clear that I'm not needed at all. And then she does what no experienced Queen would do; she takes time to crow her victory, even singing part of a song that I can swear is somehow familiar. Twilight frees me, and I can see my chance.

I said a Queen's relationship with her first host is symbiotic in nature, and I was not lying. As he supports us, we support him; it is in our interests for him to be successful, after all. I close my eyes, the last reserves of my own energy spent on a pretty illusion as I re-establish our bond.

It's like fire in the air; sharp, blistering hot and with a mind entirely of its own. Thoughts and feelings and images I can barely describe surge through me and burst out into the connection, his reserves bolstering as I pulse magic drawn from out the air itself into him. We glow, rising off the ground as the after-effects take over; the atmosphere around us shimmering and flickering in a rhythmic beat of light as energy races towards us.

A changeling Queen now rules over all of Canterlot, Celestia has been defeated and Luna will soon follow. It is the triumph my race has been dreaming of for centuries. Soon, a Swarm will be birthed from a mother that will cover all of Equestria, and perhaps spread from here to the other kingdoms, land after land falling to our might. But she is not my mother and this is not my Swarm. This is a rival Queen intruding upon my territory. And Love? Love, above all else it said to be, is possessive, self-centred and very, very selfish.

She turns, and her eyes lock onto mine with a look of heart-felt horror and betrayal. I do not blame her. We are sisters, after all.

“He's mine,” I send as the Barrier explodes in full force around us.

*****

We win, of course, my Shining Armor and me. The enemy’s expelled, the damage undone and after all, there's a Royal Wedding to be had. Perhaps after that there'll be a honeymoon. I very much doubt anypony will see us after that.