When this is all over, some of you will call me a monster. Some of you will curse my name. Some of you will look upon me in horror, wondering how someone can go so wrong. I’m sure some of you will even make up bedtime stories about me with which to scare your foals. “Ooh, make sure to behave yourself, or he will come get you.” Or, “Eat your greens, you know how he feels about little ponies that don’t eat.” But you should know this: everything I did, I did with your best interests in mind. It was all for you. For Equestria. For love. I did what your Princess didn’t have the stomach to do, and in doing so, I spared her from the inevitability of doing it.
The idea first came to mind after I discovered one of their number hiding in a small border town by the name of Appleloosa. It was a mere accident, me stumbling upon them when I showed up in a general store for more supplies on my aimless travels. Instead, I found an open basement door and a cocoon holding what I assume was the shop owner, though I had just chatted with the shop owner about the economic situation in the Griffon Empire. I turned just before my attacker struck me, thankfully deflecting what would have been a knock-out blow had it hit the back of my head. Reeling, but still remembering ancient legends of shapeshifting demons, I pulled a box of iron nails out of my pack and flung them at my attacker, earning a shriek of pain and freedom for both me and the shopkeeper.
After dispatching with the creature, I began my research. I sought texts of ancient myths, modern biology, and legendary monsters all over the world, finding books in any library I came across and stopping to scan them for anything about the creature I had encountered. Most times, these endeavors came up empty, but after a year or so, what little I had gained began to weave a picture. You must read between the lines when it comes to old myths and legends, you see. What I found was simply astonishing: a creature of darkness that fed upon the loving force all other creatures can feel for one another, using the sheer emotional energy to fuel their hearts the way hay will for a pony or meat will for a griffon. A monster that could assume the form of any other creature it wished and feed off the loving relationships it held with others, using hypnosis and mind-altering magic to cement its place in the target’s heart. The manipulation, the suffering bought on by these creatures that we would never know about, it simply boggles the mind. How many loved ones have been replaced by these things? How many loving, caring creatures have been stolen from the arms of those they care about just so these beasts might have a meal? I fear we may never know.
At this point, I of course knew what had to be done. These things threatened the safety of every pony, griffon, minotaur…anything that had love in its heart. And so, I had to determine what their weaknesses were. Again, this was no easy task. I only knew about the aversion to iron and their need to feed on love through what little I had gleaned from the texts. Further knowledge would have to be acquired through old-fashioned experimentation. After capturing my first live subject, another little demon substituting itself for a filly in a tiny village on the border with the Crystal Empire, I commenced my first and easiest experiments: how long one of them could survive without food. The answer turned out to be a week, give or take half a day, as this was how long it took for the pleas of mercy and food to cease emanating from the little thing’s cage. Even then, I dared not journey close for fear of offering a small snack to the creature and thus polluting the results of my test, so after a full twenty-four hours of silence from the prison, I finally drew near to confirm that it had, in fact, starved to death.
After that, progress accelerated in leaps and bounds. I used the lessons I learned in capturing my first subject and applied them to the second, and then the lessons learned there aided in finding my third, then the fourth, and the fifth, and so on. After a few years of experimentation with various substances, I finally determined the mechanism with which they captured love from their victims. I will not bore you with the details here, but I can assure you that my notes hold all the keys to the way they feed. These notes can be found here, in the upper dresser drawer of my hotel room, should the need to know ever dawn upon an inquisitive mind. They can be transcribed for posterity, of course. I doubt I shall have any further use for them after this night.
After discerning the biological mechanisms that permitted them to "feed," it was simple to whip together a type of poison which took advantage of this process. I required quite a few test subjects then, but after the first fifteen were all successes, I was happy to conclude that I had developed a substance nearly harmless to most creatures, but absolutely fatal to any of the demons that attempted to feed off their love. Sure, there was the odd allergic reaction in some, but progress can hardly be made without its failures, can it? On the whole, I was truly pleased with my poison, though I lacked a method of distribution. That would come later; as once again, my next great breakthrough would come as I continued my aimless wondering.
After some time of puzzling through the problem of mass distribution, I stumbled upon a tiny civilization of fuzzy, cat-like creatures. “Bushwoolies,” I call them. They were nigh-defenseless with loving trust for any other being that wondered into their territory. In other words, they were perfect bait. Thus, my experiments began anew, fuelled by the rush I received with the knowledge that I had finally come across the answer to my problem! Distributing my poison to the Bushwoolie community was but a simple task. They were concentrated in and around a single village, with a single water source. Uncovering a cave that led directly to the aquifer supplying this well only simplified my task, and I set up a camp where, over time, I was able to add a steady supply of my serum to the entire Bushwoolie drinking water supply, building it up in each of their little bodies until they were all soaking in it. Sure, there was the unfortunate side-effect that caused some brand of early-onset senility in each of the Bushwoolies, which became more and more apparent in my weekly visits, but while regrettable, this suited my purposes just fine. Though they had been reduced to a group of cooing, smiling simpletons, the Bushwoolies had become even closer to being the ideal bait for the monsters I had been hunting all these years.
Unfortunately, this did not mean success came right away. Though I had the perfect bait, the black beasts had a steady supply of food. Why alter their routines for the sake of harassing a small, unnoticeable community of semi-coherent fuzzballs? But I was patient. I had come too far to quit now. And I waited. My patience was finally rewarded with the royal wedding of some guard captain and a princess whose names escape me. While horrified at first, I was overwhelmingly relieved by the demons’ defeat, and what’s more, the papers even gave them a name at last: “Changelings.” Brilliant journalism, that. I honestly can’t believe I hadn’t thought of it first. It does fit them so well, doesn’t it?
The incredible fortune didn’t end there. The exiled monsters wound up landing right next to my poisoned little pool of love, and with their infiltrators either amongst their defeated ranks or swiftly being rounded up by a freshly-aware pony populace they had no choice but to draw from it. I was practically besides myself with joy. Over a decade of work, devoted to ridding the world of this threat, and it was about to come to fruition! And all I had to do was watch as the changelings rose, rebuilding their Empire on the backs of the Bushwoolies, not knowing that every second spent with the little furballs was death, the poison slowly building up in their black, furless, loveless bodies.
Now, even after reading the coherency of my writings, some of you will still endeavor to label me a madpony. A maniac, a drooling reject of society who could only make himself feel better by bringing about the destruction of an entire race. This image is positively wrong, and I know this for a fact. But how, you may ask? How can I be so certain when it is well noted that the insane cannot diagnose themselves? Simple: I made an antidote. You see, as time went on and I wondered about with the potion weighing in both my pack and upon my mind, it occurred to me that I might accidentally dose a changeling from whom I might wish to gather questions. Or, possibly, I might change my mind about the entire endeavor to end their threat to ponydom forever. Genocide is, after all, not something to be taken lightly, no matter how justified it may be. Hence, I fabricated an antidote in the years before encountering the Bushwoolies, one that negated the effects of the poison so long as the affected changeling was given it within a certain time frame of being dosed with a lethal amount of the poison. So tell me, do these sound like the actions of an insane mind?
For even more proof, consider this: I gave the changelings a second chance. I kept watch on their kingdom as they rebuilt, not knowing of the poison slowly building up within their entire fetid species, of the doom looming over each and every one of their wicked black heads. They could have thrived on the love of the Bushwoolies for years, and while the little creatures would have paid, this could have been an acceptable arrangement for all of Equestria. If they had just remained as they were, if the changelings had only stayed within their walls, I would have given them the antidote. I would have given them everything they needed to save themselves.
But no. Their greed truly knew no bounds, for hardly a year passed before they tried yet another plot for the conquest of Equestria, this time stooping so low as to kidnap a few fillies in order to lure the Elements of Harmony into combat. The moment I saw the small pod containing three, fearful little ponies pass within the gates of that wicked castle, my mind was made up. I simply packed my things and left, dumping the dosages of antidote I had made up in a nearby stream and burying my notes for making it. You will also find a map to the location of this burial site, again, merely for recording my discoveries for posterity. I highly doubt there shall be much need for it beyond that after tonight.
You see, tonight is the night. By my calculations, the poison will have built up enough within the changeling population as a whole for the first of the symptoms to appear. There are five stages to my potion’s effects, starting with shivers and a low-grade fever. Stage Two, growing fever and body pains with uncontrollable coughing jags. Stage Three, loss of motor control and most bodily functions. Stage Four, rapid seizures and body spasms. Here, it is also worth noting that the body pains become absolutely agonizing. Or so I have surmised from the screams of changelings entering this stage in my tests.
Finally, this leads us to the final stage: death by exsanguination, by bleeding out to the point where the body simply cannot sustain itself any longer. I must say, it is quite the gruesome sight. Here, the body’s organs rapidly break down into a sort of slurry, which is expelled from every orifice in a manner similar to some of the more exotic fevers we have encountered recently in the lands of Zebrica. It is quite excruciating, but unavoidable as a means to death. I have scoured the world for some substance that produced a more tolerable means to death, but to no avail. There was simply no poison that accomplished this serum's tasks as efficiently or as effectively. You see now, even more evidence proclaiming my sanity and righteousness! Does this endeavor sound like the result of an unsound mind!? I should say not!
The clocktower outside my hotel window just struck a quarter to midnight. At midnight on the dot, the first symptoms should begin to appear in the changeling populace at their horrid, nightmarish castle. And at 12:01, I plan on ending my life using the dagger I bought earlier today at a small general store a couple blocks down the street. I do wish to apologize to the mare who sold me the dagger. I know she never would have done so had she known my plans for it, but still, it had to be done. I only wish for the record to show how sorry I am for this final deception.
I think it will be around noon before somepony busts down this door, and then perhaps another fifteen minutes before they get over their initial shock of discovering my body to even begin reading this letter. Maybe it will be half an hour to comprehend its meaning, possibly more if they’re particularly thick, and then, upwards of half a day to relay this information to anyone of importance. By then, the symptoms will have sunken their roots deep into the shattered remnants of the changeling civilization, so even assuming this information isn’t just dismissed as the ravings of a madpony and that there is some high-ranking pony somewhere who actually cares about what happens to the little insects (highly doubtful, considering the results of the Canterlot wedding invasion), it will all be too late. The last of the changelings will begin feeling the final symptoms of the poison, entering the irreversible shivers phase, which will lead them to total, unavoidable extinction within a week, beyond the help of even my antidote.
As a final thought, let this be known: I am not a monster. I know this because I have cleansed the world of monsters. You do not know my name, but you will soon. You all will soon.
Author's Note
Just a quick something I threw together. Just had an idea for this evil plan, and a mood to write in the style of some evil, sociopathic mastermind.
...
That sounded less crazy in my head. 
