Pony vs. Pony

by s00perguy

Rating: mature
Tags: Other, Tragedy, Gore, Dark, Sad, Main 6, My Little Pony: Friendship is Magic
Length: 6991

Your favorite ponies fight to the death!

It began as a little thing I did in one night, and it was going to be all I'd do, but now it has blossomed into quite the hit. Relatively speaking. Now I'm accepting all challenges. You pick em and I'll have them fight to the death, and the victor may not always be who you think. Rematch requests welcome after match 10 has been written.

Published 2012-07-24 23:04:01 UTC
Last updated 2012-08-14 17:26:16 UTC

Applejack vs. Rainbow Dash

Pony vs. Pony: Rainbow Dash Versus Applejack

"What. The. Buck. Did you just say to me?" Rainbow growled, her voice low and her eyes dark.
"Ah said," Applejack repeated "that Ah'm goin' to tell every pony in Ponyville what Ah heard coming from Twi's house yesterday, and show 'em the proof, you freakish filly-fooler!"
"How dare you! I thought you were my friend! I thought I could count on you!" Rainbow Dash exclaimed, her legs spread in defiance, mere inches from the face of her once friend
Yeah, Ah was, but Ah'm the Element of Honesty, sugar, and that means that Ah tell the truth!" Applejack emphasized by stamping a hoof on the ground. "An' that means that Ah tell you when I think what you're doin' with that mare is sick!"
Snap.
Before Applejack knew it was coming, Rainbow Dash's lightning fast hoof found Applejack's jaw, Rainbow roaring in a fury that would have even a dragon shaking in its scales.
Laid out flat on the ground, Applejack lifted her head to look her attacker in the eye.
"You really shouldn't a' done that, Rainbow." Applejack whispered darkly. "Now you've gone and pissed me off. Ah really hope you know what you're gettin' into." She finished, standing and turning on her heel and began to walk toward the barn.
"What are you afraid of, you bucking bigot?! Afraid I'll kick your country pony ass to next Tuesday?" Rainbow jeered after her.
Applejack grinned menacingly at the clueless Pegasus. "Not quite, Hun. Just grabbin' a little somethin'." she called back, disappearing behind the door as she rummaged in a pile of what sounded like metal.
When Applejack returned, she was wielding a sword. A Zwiehander as longer as she was tall, held in her hooves by magnetic hoof covers.
The awkward looking weapon appeared to be very old, the pattern etched into the blade vaguely resembling the branches of an apple tree. A green trim, miraculously preserved through the ages, outlined the branches, which all flowed toward the hilt, the handle of which was bound in worn leather from repeated use, ending in the pommel, which had set within it a flawless ruby shaped like an apple.
"This," Applejack explained, "Is the sword, Wingless, passed down from mah great-great-grandpappy, who was a warrior in the Pony Wars back when Equestria was still in disharmony. It was created for one purpose, and that purpose was to ground a Pegasus, to make them fight on our terms. Or to make it nice and simple for you, the magic that lets you fly no longer works." Applejack said, a grim expression washing over her face before setting her mouth into a determined line.
Applejack stood, battle-ready for the coming battle, taking on the determined stance her brother had taught her long ago, the sun glinting off of her similarly patterned gauntlets and armor, making the brilliant greens and reds in the light armor she wore shine all the brighter, the weightlessly forged steel glinting in the sunlight.
"Impressive," Rainbow Dash lightly commented, her expression remaining neutral, save for a raised eyebrow in consideration of her lightly armored foe. "but fortunately for me, your precious sword only stops the magic that makes me fly."
"That's the idea. And that's all that you've got. Even your weather magic doesn't work unless you're in contact with a cloud." AJ spat.
"True enough," Rainbow relented, a sly smile creeping over her lips. "but Pegasus have a magic that you don't know about." Rainbow said, her smile having grown into a deadly grin.
"And that would be?" Applejack queried, keeping her face neutral as beads of sweat grew on her back.
"Teleportation of inanimate objects." Rainbow revealed, raising her hoof to a previously unnoticed rain loud in the sparsely clouded country sky.
Suddenly, the white cloud flashed black, shortly before a bolt of lightning shot from within, striking Dash's outstretched hoof, blinding Applejack.
When she had finally cleared the spots from her eyes, AJ couldn't help but stare at the scene before her. Walking from within the crater created by Rainbow's teleportation magic, was Rainbow Dash, dressed and armed for battle, electricity snapping throughout her armor, glowing blue as it worked its way to the ground.
The armor, simple and light to be fair to her opponent, had no outstanding design other than the black lightning bolt pattern that traced its way from her gauntlets to the shinguards she wore, respectfully omitting a helmet and boots for an even match to the similarly armed Applejack.
Rainbow's weapon of choice glinted in its sheath, the shine refracting into the colors of her rainbow mane, clinking lightly against the Cloud Steel on her back.
Rainbow drew her sword, allowing Applejack a moment to marvel at the craftsmanship.
The single handed sword, styled after a classic broad sword, had a design as intricate as that of her opponent's.
The pommel was inlaid with a hollow crystal filled with liquid rainbow, shimmering it's colors through the facets of its container. The whole of the blade seemed to possess an aura that glowed with more colors than AJ had ever seen.
A dim blue glow caught Applejack's attention emanatimg from Rainbow's armored gloves, the one in contact with the blade glowing slightly brighter than the other. Applejack thought they were just magnetic like her own, until she noticed the glow: it was electricity. Crackling blue energy sparked between ridges on the gloves and between the sword, flowing into the weapon to give the white steel a dim blue glow.
"What a coincidence," Rainbow smiled. "my sword has a story too. It was given to me by Black Storm, the decendant of the greatest warrior ever to live in Cloudsdale. Meet Silver Lining. Legend has it he gets sharper the more I use him... Still wanna do this, or are you finally gonna back down?" Rainbow finished, a dangerous spark in her eyes.
"Hell yeah, Ah've been meanin' to set you straight fer a long time, but now with this..." Applejack glared at the right armored Pegasus. "All bets are off!" Applejack screamed, launching herself at her target.
Deftly avoided by Rainbow, Applejack turned with speed that rivaled Dash to block her counter, causing the Pegasus' arm to bounce back before she was ready, knocking her off balance.
Her blade pointed at the ground from the block, and wanting to take advantage of her opponents weakness, AJ wasted no time in smashing the mare with her upturned pommel, putting the weight of the weapon behind the strike, knocking the dazed Pegasus down.
As Rainbow's rattled mind still spun from the farm pony's powerful strike, she realized that she was swiftly coming down with a full force thrust to the spot where Rainbow still lay.
A wild swing of Rainbow's blade, which deflected the large blade was all that prevented Applejack's blade from skewering the dizzy mare on the spot.
As Applejack's blade buried into the ground, it stuck fast, giving Rainbow time to role away from the infamously strong legs that tried to kick at her ribs while withdrawing the weapon.
Regaining her sense of balance and coordination, and allowing her head time time stop spinning, Rainbow realized that her opponent was able to recover their weapon faster than expected, and was coming for another attack.
This time, Dash was ready, guarding with the base of the blade to put as much of her power into the block as possible, stopping the heavy blade dead in its tracks, and, bracing herself with one hoof set back, delivered a kick straight to Applejack's chest, causing her to grunt from the impact and take a half-step back before regaining her balance Inctime for Dash's flurry of high speed strikes.
The hits came so fast to Applejack that they felt like someone was simply pushing with all their might against her heavy sword, as she blocked each strike in turn, barely keeping up with Dash's strikes by watching only the angle of her wrist, the only thing moving slowly enough to be seen.
Suddenly, just as AJ was about begin to tire, a huge explosion blew the two warriors away from one another, a plethora of colors washing over Applejack upon landing.
"What in the hay was that?!" Applejack demanded, buying time while her ears stopped ringing.
"That, my dearest Applejack," Rainbow said, a devious sparkle in her eye, "was a Sonic Rainboom!"
"What? I thought that that could only happen while you were flyin'?" Applejack shouted in frustration, glancing at the area leveled around them.
"No, I just need to go fast enough." Rainbow bragged. "I used to need my wings, but now I can do it with any part of my body." this brought a smile to Rainbow's lips. "It means that you don't have a chance of winning. You may as well give up."
"Ah don't think so!" the powerful pony roared, coming at Rainbow with a renewed strength, furious that it was even suggested she'd give up with out a fight. Now it was really personal.
Rainbow had never seen her friend move so fast. Applejack was keeping up with Dash's strikes, blocking each while focused only on her eyes, a furious fire burning within.
When she saw Applejack rearing back to put her body weight behind her strike, Dash saw an opportunity for her secret weapon, and took it, her free hand clapping with her sword hand as she took the full force of the blow, allowing it to throw her back, while still staying on her feet.
"Now!" yelled the Rainbow Pegasus, clasping her sword with both hands, the contents of the hollow crystal clearly draining into the hilt.
Applejack barely registered Rainbow's words, until the sword began to glow brightly.
Obviously suspecting a trick, AJ's attack faltered, giving Rainbow the time she needed.
Pulling with all her might, the secret of Silver Lining was revealed: a second, ethereal looking blade that phased out out of the first, this blade looking like rainbow weaponized. The total width of the two swords was equal to that of the original, and while on looked like a thinner version, the other appeared as though the colors of the rainbow had been weaver into a blade.
"Now... With the help of Clear Day... It's time to DIE!" Rainbow screamed, a feral look in her eyes as she no longer fought with the blades, and it appeared the blades simply fought while her body danced behind them like flowing silk, a deadly dance of flashing steel, her mane and tail flowing behind her.
Applejack was exhausted now. More so than she had been in any work day. The long minutes of battle felt like hours, and after her emotions running so high, her reserves were dwindling. Rainbow did not seem to be tiring, and the sweat from Applejack's efforts was dripping out of her armor. She wasn't giving up, but she was definitely slowing down.
Rainbow was tired. Actually, she couldn't think of a word for how tired she was. She couldn't think at all. She could see AJ was slowing down, but she wasn't sure it was fast enough to keep from dropping from exhaustion. The Sonic Rainboom had taken a lot out of her, speeding her up as it may have done, and now she was regretting it. The sweat had matted her mane, and the only thing keeping it out of her eyes was her gyrating motions and high speed attacks. Someone was going to win, and they were going to win very soon.
Suddenly, Applejack dropped her blade. She had simply lost her grip, but with the blade went her will. She was done.
Rainbow stopped, her muscles screaming in pain, worked to breaking. AJ had dropped her blade, and now she could stop and rest. There were nicks and scrapes from close calls all over Applejack's exposed skin, but Rainbow's were worse. Though she was not hit nearly as many times, each hit had been made to count. She could feel blood in her chest plate where an especially hard hit had pierced rhe left side of her armor only to stop at the rib. Her ankle was sprained from the frantic kicking she had received while on the ground, and a cut on her cheek from when she had first been rushed. She wasn't nearly as fast as she thought she was.
Applejack was definitely happy that Rainbow had decided to let her live a while longer, but she couldn't understand why... That is until she noticed the trickle of blood making trails down her face and a red line on her leg armor.
Applejack wasn't in such good shape herself. She was exhausted, and so cut up by mostly superficial wounds that her cost was tinted a darker orange than normal.
"Well, are you gonna buckin' kill me, bitch? Cause Ah'm done. Ah can't fight no more." AJ said, finally letting her exhaustion show through, gasping for breath.
"Yeah, I think I just might." Rainbow said, walking to just outside of Applejack's range, in case she had more strength than she was letting on.
"You know, you could just.... Let it go. We can walk away from here, and no pony needs to know. You can leave me and Twilight alone, and you can just go home. " Rainbow sighed. As insanely angry as she was, she knew the pony would be honest and tell her what she needed to hear, one way or another.
"No." the powerful pony whispered. "If Ah do that, that would be me acceptin' what you do, and Ah don't. Ah can't, in any fashion, justify just lettin' go. Ah'm sorry Rainbow, but it's not gonna go down like that. You knew that from the start."
"Yeah, I did," Rainbow snarled, "I also know that I'm not gonna kill you. Not here, not now. You're in no condition to go anywhere for a while, so I figure that I can at least wait around for a day or two to see if you won't change your mind." Dash answered, turning her back to walk away from the paralyzed opponent still bleeding into her armor.
Without warning, in one smooth motion, Applejack got to her feet in one last push, tightened her muscles, and lunged at her target, screaming like a wild beast.
In a motion too fast for either to react, Rainbow whipped around and threw Silver Lining into the charging mare's windpipe, stopping her breathing and her charge.
Before she could even slow down from her rushing attack, Rainbow tackled AJ, ripping out the blade, which had miraculously not hit either of the main blood vessels.
"God. Damn. It. Why. Did. You. Have. To. Be. So. Bucking. Stubborn?!" Rainbow screamed in rage, punctuation each word with a thrust into AJ.
Standing up, Rainbow walked silently to the farmhouse where the family wasn't. It was their vacation this week. AJ had promised to take care of the farm while her folks were away.
Cleaning her wounds with her shaking, now unarmored hooves, she began to dress her cuts and bruises. She then proceeded to clean up the mess.
She went to another town. She wanted to start a life of her own. She wanted a different life. All of these were the different explanations that Rainbow had thought up to explain AJ's disappearance. She'd decide later. She had a funeral to go to.

The End

Author's Note: Wow, that took on a whole lot darker tone than I though it would. I honestly though I would be able to stick to the script I'd come up with. I believed that I could keep it as a straight up fight, but that pre-fight simply evolved on its own. Afte that, the story literally took on its own life and grew all on its own. It's not what I expected, but I'll stand by it. This is mine, no matter how you look at it. I'll use this as my case in point when I say that you shouldn't make sacrifices for the reader. Don't censor yourself for the weak stomached ones. This is my real message to you guys.
Sorry about the emotion there guys, but I felt all of that. I really do want you guys to never hold back in your writings, and never not write it just because someone else has done it doesn't mean you can't do it too.
Now that the sad bits are handled, here's what some of my thoughts were while writing this fic, as far as concepts go.
As I felt the whole fight was very one sided in favor of Rainbow Dash's generic rendition how she is in the show, I decided to just blow it out of proportion with the some of the weapons designs that popped into my head reading Crimson Night, deciding that if Hasbrohoof had given a very Soul Caliber feel to his Celestia vs Luna fight, I felt I was well within my creative rights to do the same, however with a crazy twist of magic. I gave the two characters the insane weapons I'd designed, converted Dash's Sonic Rainboom into something a little more combat related, and went from there. And for those not familiar with weapon terminology, a Zweihander is a large, two handed sword, the design in my head of which took after the Zweihander held by Nightmare in Soul Caliber in terms of size, though not much else... The most difficult thing, I have to say, was giving appropriate names to the weapons. Yes, I know Clear Day was kinda lame for the rainbow sword, but two things played into the choice. It had to compliment the name Silver Lining, and it was 1 in the morning. I haven't stopped writing since I started this thing. I have literally been writing for the past four and a half hours since nine. Ugh, I sooooo need to sleep now, but this has been fun. I havent been this inspired since a year ago when I wrote the first two pages over two hours of a story that simply appeared in my head that night. This was REALLY FUN.

P.S. believe it or not, this is my first venture into melee combat, or at least with weapons, and my second otherwise. I really hope that the battle and the descriptions were as awesome as they were in my head, and I hope yu enjoyed the weapons just as much as I did, what with my probable fetish for any variety of weapons. But there is something admittedly different about hand to hand. It has a flow and poetry to it that I simply find difficult to do with bows and guns or magic. It is a very intimate variety of combat that can be easily filled with emotion and suspense, or at least that's what I feel while writing.
Also, to Hasbrohoof, I thank you for giving me at least the opportunity to write this and taking my publishing virginity. Hahahahaha. I don't know if I can do this kind of work consistently, but I sure hope so! Thank you again for giving me permission to mess around with your idea and do my thing.

Intermission: Dawn vs. Ghouls

Fury.
That was what was in Dawn's eyes, her gauntlets, Ares and Mars, glinting in the light as she glared at the camp of ghouls below.
'20 ghouls? Not enough, but it'll do for now.' Dawn thought, snapping the katana blades onto her gauntlets with just a thought.
"Time to test out the new hardware!" shouted Dawn.
With a roar, Dawn broke cover, screaming with pure rage as she cut into the first ghoul, whose head promptly fell off of his shoulders and his legs were suddenly detached.
This brought the attention of the ghouls in the camp, which began loping over, launching themselves at the invader.
A flash of steel, Dawn became a bladed whirlwind, and various limbs and sections of the first ghouls fell around her with a wet splat
Their blood spattered on her face, Dawn's dark eyes took on a predatory vacancy as she bared her teeth, detaching the blade from Ares and swapping it for a scythe blade hanging off of her hip.
Launching herself into the remaining ghouls, five of which were missing limbs, only eight of which were intact.
As the first ghoul stepped into her range, she impaled its skull on the scythe, planting a foot on its jaw and giving a mighty heave, cleaving its face in half before removing its head with Mars' katana.
On the swing to remove the head of to present focus of her fury, Dawn spied another ghoul reaching out to attack. Following through on her swing, she detached the katana blade from Mars, opting for the sai blade attached to her shoulder, using the curves of the blade to impale and remove the ghoul's hand at the wrist.
Screaming, the ghoul lunged again, trying to tackle her to the ground as its companions closed in.
"Fuck this 'one at a time' shit." Dawn snarled to herself, stacking the gauntlets on top of each other as they bonded with each other, raising her hands behind her head... Where a long samurai blade awaited her commanded to attach.
With a mighty downward swing, she cleaved to body of the one handed ghoul neatly in two, the others swiftly surrounding her.
"Think you're fucking clever, getting behind me? Think again!" Dawn said, malice lacing her voice.
With a high speed swing, Dawn whirled around, swiftly separating the top halves of the ghouls from their bottom halves.
Reduced to crawling on their hands, the ghouls still tried to approach Dawn, their dead, vacant eyes focused entirely on her.
Suddenly, Dawn heard a roar come from within the forest.
"An ambush? Man, you guys don't know when to give up, do you? Alright, fine, let's play!" Dawn said to no one in particular, separating Ares and Mars, replacing the blade on her back, then reaching over to her hips, which had a pair of hook swords at the ready.
The horde came slowly at first, having to navigate the trees of the tightly grown wood, but Dawn could tell their number was mic higher than this pathetic band.
Counting forty and change, her mouth pulled into a line of fierce determination, the hook blades making a fizzing sound, confirming their attachment to the gauntlets.
"Alright! Come get some!" Dawn roared, sprinting forward, leaping the 20 foot gap that separated her from the horde.
As Dawn landed, she kicked down hard on the skull of the ghoul she had landed on, easily snapping his neck, swinging out with the first blade which embedded itself in the torso of the ghoul, which she swung into the crowd, bowling over ten, tearing through the rotten flesh.
Latching the blade around the neck of a sturdy ghoul, Dawn planted her feet on its chest, giving another mighty leap into the thick of the crowd, removing its head in the process.
While flinging herself through the air, Dawn detached the blades to her hips, exchanging them for the scimitar blades on her thigh, the steel glinting in the twilight with a red tinge from the setting sun, as though already covered in her enemy's dead blood.
Flashing the blades, she made short work of limbs and heads, driving Ares through a ghoul's throat and gutting it like a fish, immobilized as it was.
Jumping back out of the crowd to a relatively safe distance, Dawn hefted a severed head on her hoof before giving it a mighty kick at the lead ghoul, causing him to stumble long enough to switch to a new weapon: jagged claws.
Leaping back into the fray, landing atop the lead ghoul, Dawn swing the claws, rending flesh and bones alike as the serration of the blades sawed through and made short work of its dead bones.
A quick spin ripped off the outstretched arms of the ghouls surrounding her, before detaching the claws to her thighs, as the gauntlets fizzled again, as what looked like one handed glaives attached themselves to the gauntlets, before she slammed her forelegs together, bonding the blades into a two bladed glaive, one on each end of the pole.
Whirling the newly created twin-headed glaive, Dawn mowed down the remainder of the main group.
Gasping for air, finally exhausting her anger, she reattached the two blades, emptying the gauntlets of weapons, before detaching the two and reaching for a katana, cutting down the seven crawlers she had made before.
"Don't want to leave a mess for someone else to clean up, now do we?" Dawn said, a sadistic smile creeping across her lips as she snapped the bloodstained blade to the armor.

Pinkie Pie vs. Rarity

Rarity vs. Pinkie Pie

Rarity was busying herself cleaning and polishing her valuables. There was the stainless steel tea kettle, her favorite for the pattern of sparkling jewels inlaid into it's handle, leading up to the spout. There was the tea set, priceless, and one of her most prized possessions.
Though certainly not her most prized possession, not by far. No, her most valued of the contents of her home were the twin daggers, curved like crescents, with a finely honed, serrated edge nearest to the handle, a smooth slashing edge taking up the upper portion.
'such barbaric times...' thought Rarity as she lifted the blades for polishing, gems of high quality studding the hilt, sparkling brightly in the setting sun.
'but such an elegant piece. Beautiful but deadly...' she thought, transfixed by the craftsmanship of the hilt and handguard, appearing as though intertwined vines of gold.
~~~
Rarity had not relished the idea of the weapons at first, but she'd found them more beautiful the longer she looked until, soon, they became her mantelpiece.
Those blades had sat there for weeks, not moving or even recieving the same thorough cleaning as the rest of the house, her attention slowly migratin to focus on them until she, one day, took the blades in her hands, getting a sense of the weight.
They felt good, the way to steel pulled down lightly on her hand as she felt the perfect balance of the weapon. She was so entranced that she did not realize what she was doing until she had done it.
She did not feel herself throw the blades into the air, spinning in their sparkling arcs. She did not consciously register the blades balanced carefully in her fingertips, she did not hear as she threw the blade into the wall, embedding it in a stud.
Only after the events occurred did she realize what her body had done without her consent. It was as though she had been doing it for years, done without though or conscious thought. She had tugged the blade out of the wall, looking over the weapon in her hand more intently before her eyes fell on the Latin inscription on the blade, which read simply as: demon slayer.
~~~
That was many a month ago, and since then, she had taken to training herself, preparing for the day when she came upon one of the enemy. She had not seen any, but she remained vigilant. The demons were crafty, and they could disguise themselves well...
Rarity absentmindedly stroked the cutting edge of the blade she was polishing, inadvertently cutting herself and hissing sharply in pain, suckling the wound and berating herself for being so careless, the pain clearing her mind to a sharp focus.
And that's when she felt it. Much like the feeling of being watched, followed by her body moving automatically, as though she were called from a great distance, her legs carrying her towards her unknown destination. This was it! A demon, at last!
Suddenly, Rarity got a faceful of pink. Pink and a set of wide, bright, energetic blue eyes, belonging to her friend, Pinkie Pie.
"Eek! Pinkie, what in Equestria are you doing sneaking up on me like that?" Rarity queried, her legs no longer carrying her forcefully along.
"I just saw you smiling all big and happy and I thought to myself, 'Pinkie, did you make Rarity smile?' and myself said 'nnnnope!' so I just had to come over and ask you why you were smiling so I know what to do next time, so Rarity, what's going on?"
One breath. One sentence. It always amazed Rarity how her gaudily bright pink friend could do that, but like everyone else who knew her, she had always put it down to Pinkie Pie just being Pinkie Pie.
Rarity sighed, somewhat drained by the party pony's energy and antics. "It's difficult to explain Pinkie, and I have some business to attend to. I'll have to tell you some time later today..."
Rarity ended her statement with a parting wave and began to walk away, her friend cheerily bouncing in the opposite direction.
And then she felt it. A gentle tug at her feet. Something within her was pulling her back, back in the other direction.
"That's strange... It must be close by... But how could I have missed it? It would have had to walk right past me..." Rarity said to herself, utterly perplexed. "Then how in Equestria did I miss it?"
Rarity mused at this as her legs carried her once more, inexorably towards her target.
"But wait... Pinkie went down this way... No, no, it has to be a coincidence. She couldn't be in cahoots with monsters such as these..."
Slowly, inescapably, her feet dragged her along, following the steps Pinkie had taken, obvious by the trail of smiles left on the faces of passers by, proving slowly to Rarity's mind, filled with denial as it was, what she feared was true as she saw her through the crowd, her own steps tracing her friend's perfectly: her true form.
It wasn't hideous or ugly or deformed as most might suspect, but it was not the Pinkie Rarity knew. No, this Pinkie's coat was a redder shade of pink than her friend, and a black mane and tail with a streak of dark pink running through it.
She was still recognizable as Pinkie, and the way everyone else around her suggested that she was no one else. And yet her legs brought her closer and closer, stalking her friend silently and invisibly, Rarity watching with horror as her own body stalked her friend with practiced ease, ducking behind barrels, synchronizing her walk with passing crowd members, casually walking into shops and out the back door, anything to avoid being seen by her prey. Finally, Pinkie left the main square of town after saying hi to what Rarity guessed was half of the town, making a beeline to Applejack's orchards, obviously on her way to catch up with her hardworking friend.
It appeared she wouldn't get the chance...
Silently, as she found it difficult to speak, she pleaded with her body or whatever forced her body to follow her friend, that forced her to the back of her mind, unable to control anything, as if she was watching it all happen on a theatre screen.
"Please! Anything but my friend! There has to be somebody else! Anybody!"
But through all of her begging, her body never stopped performing its mission, stalking Pinkie Pie until finally she was all alone in the middle of the orchard, still making her way to Applejack's home some 2 or more miles away.
Now her body switched attitudes. Something had judged their distance from Ponyville sufficient to make its move. Suddenly she was standing straight, sprinting for Pinkie as the knife flew out of its sheath, Rarity's hands moving without her volition.
'Nononono! Not like this! I can't do this to her! Please! Stop!'
40 feet, and closing fast.
'How can I stop this? I have to warn her! Give her a chance to get away!'
20 feet, her legs are tense, preparing to jump.
'Oh Celestia, please no!'
10 feet, a mighty leap sent her catapulting through the air.
"PINKIE!!!" Rarity screamed, a desperate energy pushing the words past her lips and out to her friends ears.
'It's too late.' Rarity thought solemnly as she flew through the air, the knife pointed towards her friend's spine, shining dimly. 'I couldn't act, and now I can't save her from myself...'
Rarity blinked. That was all it took, and suddenly the pink mare was gone. She had simply disappeared, the knife slashing through open air, the dark orchard making it difficult to see her surroundings as her eyes readjusted to the dim lighting.
"You've made a terrible mistake, slayer." said a voice from nowhere. Pinkie's voice, but with a tinge of cruelty in it. "I have tried successfully to live in harmony with the residents of this place. Leave me be now, and we can both go home. I will defend myself if I must." the voice implored Rarity, obviously unaware of her being controlled.
"P-Pinkie?" Rarity rasped, regaining control over her tongue for the moment. "It's me, Rarity."
There was a long pause before Pinkie spoke again.
"Rarity? What are you doing here?" Pinkie dropped down from a tree above. "Why aren't you in Ponyville back at the boutique?"
"I-I... I'm sorry Pinkie..." Her hands readied both blades. "I can't stop myself. I'm trying so hard, but I simply cannot..."
Rarity's hands lashed out, her control utterly lost as the daggers weaves through the air, making aggressive slashes at the party pony, who nimbly jumped back.
"Rarity, what in Tartarus are you doing?" Pinkie cried out, dodging her friend with practiced, if confused, ease.
"I-it's these weapons! I'm not in control anymore!" Rarity strained, trying to gain a semblance of control over her slashing body, her shuffling advance, anything to give her friend a chance to survive.
"I-I'm sorry... I'm so sorry..." Rarity hung her head, her body perfectly aware of where the pink mare was without looking up. "I can't help you. I'm resisting, but I can hardly slow down. You'll have to kill me."
Pinkie gasped, horrified. "B-but-"
"Pinkie, you're going to do this, or you're going to die! Do you understand that?! I can't let myself hurt you, no matter what you are. Now kill me while I still have control and sanity left!"
Reluctantly, Pinkie hopped away, sidestepping yet another slash, which was followed by a narrowly avoided trip kick.
"I understand. I'll... I'll try to make it quick."
Pinkie hopped out of sight behind a tree, perhaps to catch her breath, Rarity's body silently stalking towards the towering resident of the forest. It was a thin tree, just enough to hide Pinkie from sight.
Rarity's arms were spread wide, daggers held sideways, slipping noiselessly towards the tree. She felt everything. She felt her legs tense up, her body fly through the air in a lunge, her grip tightening on the specialized blades, her arms wrapping around the tree, daggers ready to lop off the head of the person on the other side... But swiped at nothing.
There was nothing. Absolutely nothing was behind this tree. No other trees to run to to hide behind or climb, as they were at the edge of the orchard, without even a tall section of grass for sanctuary.
The blades had dug deep gouges in the tough bark, and they were stuck fast, a moment's hesitation before Rarity's hooves began to tug at the blades to loosen Nature's hold on the cold steel.
"Not so fast!"
Pinkie's voice came from above, attracting her attention.
Looking up, she got a face full of hoof for her trouble, the kick sending Rarity flying backwards, slamming her into another tree, making her see stars, her personal sense of orientation thrown completely out of whack.
Her body, however, did not have this problem, launching itself to its feet quickly.
"I really don't want to do this... But if I must... I'll do it my way!" Pinkie lamented, reaching behind herself, and though she wore nothing in which to conceal it (if, indeed, such a massive thing could be concealed), pulled a large glaive from behind her back, setting herself into a combat stance.
The glaive was an elegant, yet powerful weapon, the blade on one end glinting in the faint moonlight, a black obsidian blade, the edge glimmering a bright, bloody crimson, as if foreshadowing the inevitable.
"Pinkie... I'm sor-" Rarity's mouth slammed shut mid-sentence, her mouth stretching into a wide, malicious grimace, the control of her face lost to the possession of the weapons. The time for talk was over.
Rarity's hands weaves through the air, cutting at her friend with a renewed ferocity, an expression of grim determination and effort painted onto her face.

Pinkie was in trouble. She was fending off her friend's attacks well enough, but the force that possessed her did not tire. She would. This hand to end soon, and she knew it. She put a plan into action that would hopefully end it quickly and painlessly.

Rarity could feel the exhaustion. The fire in her limbs, and the heat of the sweat on her brow. If it were her, she would have dropped from exhaustion right then and there.
But it wasn't her, and she knew it. Whatever this thing was, it definitely wasn't her doing. Small comfort, knowing that it was still her body trying to drive a blade trough her friend's throat.

Pinkie sidestepped yet another slash of the blades, blocking it with the pole of the glaive, the tough wood hardly scratched by the blade. Now was the time to act, or she may not get another chance to save her friend.

Rarity struck, and Pinkie jumped away, ducking behind a tree. Not wanting to let her escape again, her body quickly peeked behind the tree, blades at the ready, not giving her the shortest moment to escape... But she was gone.

Pinkie ducked behind the tree, and began her plan. Darkness folded in around her, and she disappeared into the shadows.
The other realm. She had no idea how, but her kind could move in the shadows. From shadow to shadow, she could move, the world that was her own frozen and darkened.
She could see the snarl on Rarity's face , still registering the empty space behind the tree. She could see her legs, tensed to pounce.
She could see her guard left wide open on her back.
Pinkie settled herself into the shadow of a large apple tree, whose shadow stretched right alongside her friend and raised the glaive, tensing her muscles for a mighty swing.
'this should be over shortly.'

Momentarily confused, Rarity saw that her friend was gone once more. But how could that be? Her body had not allowed even the best climber time enough to scale another tree.
Then she saw it. Red. Just a glimmer of blood red out of the corner of her eye. The rest happened so fast, she simply couldn't register anything but the end result. There was her friend, on the ground, and she was bleeding. She was bleeding a lot.

Pinkie started her swing. She put all of her speed and power into that one stroke, before noticing her fatal mistake: her friends head was turned just enough to see the irises of her blue eyes. She had been seen.
Before she could put a guard up, before she could lower the pole in even a half attempt at blocking the attack, Rarity batted away the glaive with one dagger, and she felt eight inches of cold, merciless steel driven into her gut, just below her navel.
Before she could cry out in pain, she felt it once more, this time higher, just below her sternum. The scream caught just on the edge of her lips as she felt the warmer, wet steel point pressed against her throat, heavy tears in her friend's eyes, apparently having gained control again, however fleeting.

In a rasping voice, as though it were a strain to speak, Rarity whispered.
"I'm so sorry. I'm so, so sorry..."
Pinkie smiled a smile. It was the same smile she gave to a foal to say everything would be alright. The same smile she used to comfort a friend in need.
"It's alright... I forgive you..." Pinkie wheezed, coughing bloodily, the crimson fluid spattering Rarity's face as she stroked her cheek gently, wiping away one of the many flowing tears from her cheek.
Rarity could feel her control slipping. Her muscles were straining to push the blade into the abomination that was the demon before her. She could feel her face beginning to slip.
"Goodbye."
All control lost, the blade plunged deep into Pinkie's windpipe, choking off her supply of air.
Horrified, Rarity could only watch, an audience member to the grisly scene unfolding before her.
Suddenly, her hands wrenched the blade to the side, tearing open her carotid artery, then back to the other, ripping open the jugular vein, the spray splattering against her closed eyelids as her body stood, showing no signs of remorse.
She wasn't going to survive. Satisfied with this, her body continued to act against her will, cleaning the blades on the grass and walking away towards town, sheathing the weapons, the image forever burned into her mind.
'It's almost morning.[i]' said a voice in her mind. 'you have a business to run.[i]'
Accepting her fate, Rarity made her way to her boutique, mourning the loss of her friend. She would need to sleep. There was going to be a lot to do tomorrow.

Start suggesting ponies now! As usual, I'll inform you of my choice as soon as one clicks for me.