Within the deepest subconscious of the Slutprincess' minds, two dark beings still lay in hiding. They were always there, in some small form, twisted by their counterparts' desires and decisions. Always listening, watching and waiting for a time when they could strike. A time when they could twist the minds of Celestia and Luna into allowing them to take over and unleash their power in their twisted endeavours. Right now though, both Daybreaker, and Nightmare Moon listened to what was happening with rapid fascination, each word that left their Master's youngling's mouth filled them with greater hopes and excitement.

[Derpibooru: 3280735]

That wasn't to say either Nightmare Moon or Daybreaker had any respect had any respect for this Rose. The useless dracony hybrid was simply filled with weakness in contrast to their Master's perfection, what interested both dark forms were the insecurities that oozed from her dark perverted fantasies. As Rose spoke of her dream of twisting the dark forms into sex slaves of their Master, Nightmare Moon and Daybreaker were thrust into fantasies of their own.

For Daybreaker it was a simple matter of savagely fucking the lesser youngling before her beloved daddy that she so desperately craved the affection of. Watching her face twist between lust and despair as her weakness was put on full display before her father's face. Nightmare Moon's cunt leaked with different, darker fantasies. Amoral desires of sexually gaslighting poor Rose to her own ends, taking advantage of the thirsty ass bitch's desperation to counterbalance the 'threat' of Nightmare Moon and Daybreaker.

The last thought was particularly absurd, neither Nightmare Moon nor Daybreaker presented a 'threat' to their Master's harem, no, the only real 'threat' was the half-measures of Celestia and Luna. Those two Slutprincesses wanted desperately to make their Master's world one where all women would be happy as his slaves, subtly and carefully, and never acknowledging what both Daybreaker and Nightmare Moon knew to be necessary.

But now, if Rose's plans came to fruition, the two would be able to enact those plans, and even take the invaluable position of Slutprincess for themselves and do what the weak Celestia and Luna would never be able to do. Before now, nothing Daybreaker and Nightmare Moon had done would allow them to weaken the Slutprincesses's mental defences, but perhaps now with their Master's request that might change. Even as both Celestia and Luna protested the two dark forms listened with rapt attention.

"Come now, aren't you both secretly attracted to your alter egos?"

The two dark forms grinned, and new memories formed in their minds of how they had leveraged the Slutprincesses’ natural attraction to them to their advantage. How in the eternal battle of wills between the Slutprincesses and their dark forms, both Nightmare Moon and Daybreaker had been eager to take advantage of this weakness, in their eternal game to within their mind, both bombarding their counterparts' minds with fantasies of the two dark forms.

"Don't you want to fuck that fiery bitch, Daybreaker, Celestia? Don't you love her huge tits? Wouldn't you love to fuck a woman with tits as big as yours?"

Within Celestia's mind, the sadistic alicorn Daybreaker smirked with pride. Naturally, their Master was right on every point, something that drove Daybreaker wild with glee. She now remembered implanting fantasies into Celestia's mind, at the most inappropriate moments, promising her such carnal pleasures if only Celestia would break from her obsessive need to play the good princesses and instead embrace Daybreaker's depravity.

She remembered one that made Celestia gush particularly well. Celestia had been holding a royal audience with a pair of nobles when she had fallen into her lewd daydream. In the dream, Daybreaker was undressing the mare who had called the tedious audience. A particularly stuffy prude who selfishly wasted her perky breasts and ample hips with her Puritan lifestyle. A thought that Daybreaker wholeheartedly agreed with, and used as a basis for the fantasy that broke into Celestia's mind.

In this fantasy, Daybreaker did not care for Celestia's pretexts and would simply ignored the protests of the weak husband and drag both the husband and wife from their Royal Court. But unlike Celestia, she had not manipulated them into joining them in her secret dungeon, but rather to the centre of Canterlot itself. There within the sight of an entire crowd of Canterlot she stripped the wife of her clothes and fucked her with a strap-on dildo shaped in the form of their Master's glorious cock before the entirety of Canterlot.

There the powerless ponies gaped in horror as Daybreaker effortlessly transformed the mare into a drooling slut, her so-called morals providing no defence against Daybreaker's raw sexual talent and her Master's strap-on. Even as a replica of their Master's tool, it was more than enough to break mares and shame colts. And the crowd could do nothing but watch, no match for Daybreaker's sheer power, and so entranced by the malevolent sex appeal that she caved under Daybreaker's touch and the hypnotic sway of the alicorn's titanic tits. Before long she would scream Daybreaker and their Master's name as she was fucked before Daybreaker's subjects. It had made for an awkward audience in the Royal Court as Celestia couldn't keep a straight face, her eyes rolling into her head and her cunt gushing from the sight of Daybreaker's psychic fantasy. She had barely managed to keep her mouth shut and excuse herself, to relieve herself in her personal sex dungeon. Thankfully Cadance had been visiting and all too eager to oblige her.

Spike continued, unaware of the new fantasies implanted in Celestia's mind when he asked Luna: "Haven't you lusted over Nightmare Moon's dark beauty? Haven't you leered at her beautiful ass in your dreams? Didn't you love being in her dark, sensual body even if you didn't like her actions?"

Luna's memories shifted, and so did Nightmare Moon's. The dark days she had spent as Nightmare Moon were no longer quite as horrific in the lunar princess’s mind. Instead many mixed feelings filtered through those memories, a sense of sexual thrill tainted those memories, as she now remembered striding through the dreams of others with her dark graceful body, drinking in their lust even as Nightmare Moon warped their dreams into vicious nightmares.

Her thousand years of exile on the moon were now filled with adventures into the dreams of many a mare in Equestria. Nightmare Moon had taken particular delight in dressing her body like a true dominatrix, spiked heels, armlets and bracelets accompanying a latex corset squeezing her juicy ass for all its worth. An outfit that would be seared into both Luna and Nightmare Moon's conquests as she conquered the dreams of mare after mare.

A few times during Nightmare Moon's particularly boring exile on the moon, the dark goddess entered her own mind and had her own fun with Luna. Straddling her lunar counterpart's face with her glorious dark ass and mocking Luna with her dark triumph and confronting her lust for her dark self. Luna had gushed quite a powerful stream across the night sky that night as Nightmare Moon hurled mocking accusations as Luna howled with both lust and arousal before being smothered into unconsciousness by the two phat asscheeks that muffled her face.

"Don't you both desire to make them your pets, your slaves, you personal fuckdolls? Doesn't that make you horny beyond measure?"

Both Nightmare Moon and Daybreaker found their grip on the Slutprincesses weakened as many of those fantasies took a very different turn. Certainly, there were still dreams and memories where twisted alicorns used the Slutprincesses against them but now there were just as many of those fantasies where the Slutprincesses turned the tables back on them.

In one dream, where Celestia was forced to watch Daybreaker enslave the Hippogriff armies with her immense power, only to then ask Daybreaker whether she would enjoy a taste of her own medicine. Soon Daybreaker felt her neck collared in chains of light and her face pushed to the floor, as Celestia summoned a strap-on of light to fuck her new slave in the ass.

Nightmare Moon felt the difference too. She had no shortage of memories teasing and flaunting her dark beauty over the lunar princess, but now they were mixed with times when Luna had turned those tables on Nightmare Moon herself, seizing the dream and fucking Nightmare Moon into submission. Worst of all, Nightmare Moon could not help but think back with shameful arousal how in the dream Luna had led Nightmare Moon onto a stripper stage and used her as a personal pet in her show.

Before either Daybreaker or Nightmare Moon could get too lost in their memories and fantasies their Master delivered his ultimatum to Celestia and Luna. "Now, answer me, my dear Slutprincesses. What do you two think? You can take the risk with my beautiful daughter-slut's challenges to make them your fuckpets or you can live without them forever. Your choice."

As the two Slutprincesses moaned and protested, both Daybreaker and Nightmare Moon were filled with newfound hope and interest. Here was their chance, their hope to truly become free of their weak alternate selves, to enslave them and do what they couldn't in their Master's name.

For Daybreaker, it meant shattering all illusion and unleashing her fiery fury upon those who wouldn't embrace their Master's rule. For Nightmare Moon, it meant reforging every woman in the world into a whore for her Master, then bring them all together in a single orgy that would last FOREVER!

“I… I consent.” Celestia could barely keep in her moans as she tweaked her nipples between her fingers, likely scissoring Daybreaker in her lust-hazed mind. “I want that bitch to eat out from my cunt!” “P, please, Master.”

Luna was in a similar state as her sister as she mindlessly humped the floor, creating a puddle from her gushing love juices and sweat. “We want to knead that ass so bad~.”

Spike shortly mused over his handiwork before turning his head toward Rose to talk about her purposed powers but neither Celestia, Luna, Daybreaker nor Nightmare Moon gave a damn about them. No. Instead, all of them were lost in thoughts with their Master's promised prize. For Daybreaker and Nightmare Moon, it was the promise of freedom from the restraining shackles. It was the promise of power, and the means to fulfil their twisted goals. But for Celestia and Luna, it was freedom from their mental struggle. It was the promise of binding their evil counterparts as their eternal slaves and fucktoys.

"So, Nightmare Rarity, if you please."

Spike’s words took them out of their fantasies and back to the matter before them. It was time. They were all so anxious, but also excited. And so horny that they were almost about to faint.

With a dark, melodic laugh, almost as beautiful as their Mistress's Nightmare Rarity stepped forward, her horn lighting up with a shadowy purple glow. Emboldened with the Root of Magic, the use of Sombra's dark magic was a trivial affair and the consequences of dark magic were of no consequence. The purple glow enveloped both Luna and Celestia, the former flinching slightly as the power of Nightmare Moon and Daybreaker were drawn out of them.

At first, they emerged as shapeless, formless forms of dark orange and midnight blue, rising from Celestia and Luna’s body like a fog. But then that fog started to concentrate, harden, and swirl together as if Nightmare Rarity was fashioning them together like a dress. And true to the analogy, her face lit up with the same joy that her counterpart would make when making her dresses, and she hummed to her tune as Rarity would do.

The bodies of Nightmare Moon and Daybreaker soon began to take shape, first torso, then limbs, then face and hair.

Unlike Sombra’s magic, Nightmare Rarity had more power and had less to fear from the consequences of the dark magic. So, she could go further than him. Such was the case that when the bodies began to form, the dark seamstresses took liberties and a few extra adjustments; Enhancing the bust of Daybreaker ever so slightly, adding a fuller and darker mane for Nightmare Moon, and maybe a good few inches to Daybreaker's height, and perhaps trim a few from Nightmare Moon's waist to accentuate those two glorious mounds. She did all this within the blink of an eye before anypony could even notice.

And with that the two dark alicorns were free, finally free. For the first time in their long, long lives, they were their own alicorns. They could breathe with their lungs, take in the sex-filled stench of the room with their nostrils and feel the carpet beneath their feet. They looked around with their own eyes for the first time, flashing both Celestia and Luna with wide grins that bordered on madness, and then those wicked eyes fell on their Master Spike and his young spawn beside her.

"Master... Are you ready to be shown what a true alicorn sex slave can do?" Nightmare Moon asked, walking towards him with a sexual strut, making every effort to sway her glorious ass with every step she took.

"Aren't you tired, Master, of skulking around in the shadows? Isn't it time that the worthless sluts of Equestria realised who their Master is, even if it's by force?" Daybreaker asked, her hands on her tits, chest thrust forward. "Just give me the order and I will unleash my full power on Equestria, burn down any pathetic resistance and drag any slut I see before you to serve you at your knees."

"No, wait..." Celestia stammered an uncharacteristic look of panic on her face. Daybreaker spared the solar princess little more than a sneer, taking great note of how Celestia's enormous tits pressed against her thin robe, and, most notably, how her nipples were as thick as grapes and hard like stone. "Our Master deserves a powerful kingdom with prosperous subjects to rule, he deserves to watch their naive faces turn to horror as they realise that their beloved princess-EEP!"

Daybreaker had marched over to Celestia as she talked, grabbed a fistful of her dress and lifted her off her hooves. But the hand that traced through Celestia's rainbow mane was surprisingly tender. "Don't lie, you manipulative slut. That is your fantasy, not your Master's, his will supersedes yours." Then she leaned into Celestia's ear. "But perhaps you'll get to experience a few of them."

"And what about you, Whore Princess?" Nightmare Moon asked, her hands on her hips her gaze directed at Luna. "How does this body look from the outside? Don't you miss it just a little? Doesn't it make you weak in the knees? Don't deny it now."

"We wouldn't dream of it." Luna said with a sharp coy smile. "Nothing would make us wetter than having you at our knees."

"You might find that a little difficult when you're tripping over your own cum." Nightmare Moon teased, shoving two fingers into Luna's pussy to get a personal feel of how wet she is.

The Nightmares laughed, and their cruel mocking laughter was joined in with the changeling queen, who was every bit as horny as the Slutprincesses, eager to watch them be turned into mewling sluts. Shamelessly fucking herself as she watched the Slutprincess be put in their place. "How does it feel, Celestia? To be driven mad by your lust for your hated enemy?"

"F-FUCKKK!" Celestia cried, let out a scream as Daybreaker bit down hard into Celestia's glorious tits.

"You pathetic slut, how do you expect to defeat me when you're entranced with my glorious tits?" Daybreaker asked, before shoving Celestia to the floor and smothering the Slutprincess of Servitude with her glorious rack and driving Celestia into a horny fantasy.

"That's a good point, Daybreaker." Spike said, his voice neither loud nor forceful, but still silencing all four alicorns. "Seems unfair if Celestia and Luna have to compete whilst slipping in her own pile of cum. But that's not a problem. After all, the feelings are mutual, aren't they?"

"Master, you fucking-fucking" Daybreaker gasped, but it was all in vain as her hesitation gave Celestia all the time she needed to thrust her own tongue down Daybreaker's throat, sending the flaming alicorn into even greater flames of heat. In the next second, Celestia had flipped positions, now with her tits thrust into the fiery alicorn's face. Her counterpart's lust sent her into a frenzy of heat that burned the carpet touching her fur.

Nightmare Moon however was put on the defensive, not familiar with Luna's transformation in the Slutprincess of Whores. Whereas in the past Nightmare Moon had preyed on Luna's insecurities, now those insecurities were gone, replaced with a newfound determination to be the ultimate Slutprincess for her Master and his cherished whore. And this confidence brought new feelings to Nightmare Moon's sex.

"The tables have turned, Nightmare Moon, we're not the whimpering perverts we were before. It is a shame we cannot say the same of you."

"Enough," Spike said, ending the argument. "Save it for the challenges. Speaking of them, Rose?"

Spike turned to his daughter, but Rose didn't pay much attention, rather she was entranced. The list of challenges in her fingers had fallen to the floor and her eyes were fixed upon the two dark alicorns, like a deer stuck in headlights, a trail of drool escaping her lips. It was all endearing for her father though, knowing what a pervert she was.

"Rose, Rose, ROSE!" Spike barked sharply, finally knocking Rose out of her reverie.

"Huh... wha?" Rose stuttered, head whipping around in a panic. "Oh fuck, I'm sorry Master, I mean Daddy. So very sorry, I-"

"Calm down," Spike said softly, a hand groping her breast, very calming for one of his slaves. "Just tell me what challenges you have thought of to prove who deserves to rule Equestria in my stead."

"R-right." Rose gasped, leaning down and picking her list up from the ground. "Well the first challenge is-"

Author's Note

I'll be honest I wrote this chapter for two reasons. One because user Jonathan Stag suggested it and even helped write some of it, and two because I'm stuck as to what Rose's sexual challenges will be.

Right now I have a kind of an idea for a Daybreaker vs Celestia challenge (including Twilight) but I'm not sure what to do for the others. I'm thinking of a best of three, with a Daybreaker vs Celestia challenge, a Nightmare Moon vs Luna challenge and a tiebreaker with all four alicorns. Suggestions would be greatly appreciated, though to be honest I may have forgotten a few ideas that people suggested so feel free to repost them.

Crowdfunding for Future Artwork here: https://ko-fi.com/darkstar239

Any suggestions, feedback, and constructive criticism are welcome.