Battle of the Sun and Moon

The two huge alicorns known as Princess Celestia and Nightmare Moon stared at one another with narrowed angry eyes within the Castle of the Two Sisters. They stood like mighty elephants in terms of size at this starting point. Nightmare Moon however, was slightly bigger since she had absorbed the wielders of the Elements of Harmony.

“You cannot stop me! I shall grow more powerful than you could ever hope to be and finally destroy you!” boomed Nightmare Moon before she flapped her wings and took flight.

Celestia gave chase, flying after her, following her out of the castle and into the Everfree Forest. The Dark Mare flew into Ponyville. The inhabitants screamed as they were turned into a rainbow mist.

“What have you done?!” shouted Celestia, filled with concern for her subjects.

“Like the elements before them, they remain unharmed. Their souls are merely bound to my immortal body. They are my subjects now, and will live inside me forever in eternal happiness. You have no hope of defeating me sister, I suggest you just give up and accept my inevitable victory!” she said, growing in size as more souls flew into her mouth.

Nightmare laughed maniacally and became drunk with ecstasy, moaning aloud as the effects of the growth flowed through her body. There came a loud slapping sound as her asscheeks smacked against each other, with a delightful sound of flesh slapping against flesh. Her body within a manner of seconds doubled in size and her hooves sank into the ground below as her body pressed down upon it with increasing weight. She now stood at about 26 feet tall.

But it didn’t stop there as with each passing second she was approximately gaining one foot in height. 26 became 27 feet, 28 feet became 29 feet, 30 feet became 31 feet…

Nightmare Moon moaned out loud as her marehood began to drip profusely. A torrent of white creamy liquid poured out of her thick and meaty, pink vagina. Her marecum flowed down the thick canyon between her rump’s bubbly cheeks, dripping freely down onto the ground below and causing a large pool of her creamy marecum to form underneath her upon the grass and caused a strong musk to fill the air, smelling faintly of blueberry pie.

“Yes! Bigger! Bigger! Make me bigger!” she cried out aloud.

Fatter and fatter, bigger and bigger, heavier and heavier, Nightmare Moon’s butt continued to grow and expand. Nightmare Moon giggled at the feeling of her hooves sinking even deeper into the earth below her.

Her massive rump jutted out from behind her like an over inflated blimp, and looked quite disproportionate to the rest of her body’s respectively large frame. Her rump was perfectly smooth and round, no hints of sag in the least, despite the huge thickness of her bloating rump, it seemed to defy gravity itself with its magnificence.

Her legs expanded to match the expanding mass of her rump, maintaining a perfectly smooth mare figure with thick, curvy hips to die for. She was nothing short of breathtaking. Even at her massive size. She seemed to get more and more beautiful the bigger she got.

At this point. Nightmare Moon now stood two times larger again, making her up to stand at least fifty feet tall or so.

Nightmare Moon’s tongue lolled out of her mouth freely as she slammed her massive ass hard upon the ground, creating two deep craters in the earth. Her expanding buttcheeks took up more and more space in the streets of Ponyville.

“Mmm, yes!” she cried. “Bigger! Bigger! I want more!” she boomed, her lolling tongue causing drool to flow down her cheeks as she was being overwhelmed with the pleasurable sensations of her growing form.

Her cheeks soon began to push against nearby buildings, the soft flesh of her ass began to deeply depress against them like soft dough. This lasted for a brief moment before her ass simply ploughed through the buildings, bulldozing them down, and smashing them into smithereens as the infrastructure could not handle the gigantic body of Nightmare Moon.

“Muahahahahahaha! You cannot hope to stop the power of our growing rump!” Nightmare Moon exclaimed, her voice resounding out across the entire town.

While this was happening Celestia, could not help but grind her hoof between her legs as she stared transfixed at Nightmare Moon’s massive, growing ass. Her hoof was already soaking wet from her dripping marehood at the sight of her corrupted sister, formally known as Princess Luna.

Celestia moaned, nearly crying out in bliss as she masturbated. Evil or not, Nightmare Moon was so sexy with an ass growing bigger and bigger, internally Celestia couldn’t help but recall every single time she proudly showed off her own ass in the past and compared Luna’s to it, only for her cheeks to now paled in comparison to Nightmare Moon’s enormous derriere, which was literally big enough to eclipse her in its majesty.

Nightmare Moon stood up and presented her massive backside to Celestia. Each cheek of her ass was now the size of Ponyville Town Hall. A river of cum was pouring down the canyon of her buttcheeks while a large pool of her creamy seed soaked the grass below while the wonderful smell of blueberry pie bombarded Celestia's senses and permeated the air around her like a sexual haze.

“Mmm, beautiful isn’t it? Your face shall be smothered by it soon enough. Won’t you like having your face used as a throne for my big fat sexy ass? Imagine it, all your worries melting away as you embrace the softness and warmth that is my beautiful ass.” said Nightmare Moon in a hot breathy voice.

Celestia blushed profusely and turned to look away, covering her face with a wing and trying to hide how much her sister’s words were getting to her.

Nightmare Moon experimentally pressed her hoof down upon her right cheek, feeling the soft fat conceding deeply from her applied pressure. A smug grin came upon her face before she lifted her hoof up, pulling it back far before giving her ass a hard slap.

Her massive buttcheeks wobbled from side to side as powerful shockwaves came out from the gigantic ass from the hard impact. The vibrations from her giant butt ended up knocking Celestia out of the sky as the resounded clap was surely heard for miles around.

Celestia landed with a loud thud as she fell to the ground, her ears ringing slightly from the thunderclap of hoof on ass.

However as her ears stopped ringing, her vision was darkened as the shadow of Nightmare Moon’s growing backside suddenly loomed over her.

“Mmmmmm! So… thick… so beautiful. It will only get thicker as I grow larger and larger.” said Nightmare Moon in a sensual tone of voice as she stared with dreamy eyes at her magnificent rump.

Nightmare Moon was so distracted by the sheer beauty of her own ass that she seemed to have forgotten Celestia existed at the moment.

And Celestia could not blame her, she also had become distracted looking at Nightmare Moon’s glorious ass. A small part of Celestia wanted to submit to Nightmare Moon right away and be sat on and engulfed by such a sexy big, fat ass her corrupted sister now possessed.

Celestia could not help but find sexy the being that was once her innocent younger sister, had now transformed even further beyond the sultry and tempting figure of Nightmare Moon into a gigantic goddess of a mare. Her huge black rump with dark purple blotches surrounding the white crescent moon cutie marks was quite a sight to behold. She found herself somewhat at ease fighting Nightmare Moon. Indeed, the Elements of Harmony made her stronger, but they had also made Nightmare Moon more compassionate.

Celestia shook her head. It was still Nightmare Moon. She needed to defeat her, even if Nightmare Moon had grown a little softer than the last time she faced her.

With that she teleported herself into her throne room, within the city of Canterlot. She stood standing over her throne with her massive ass now seeming to be far too large for it.

There was no one else present in the throne room apart from herself.

She sighed deeply. “I’m sorry about this, my dear subjects. But it is the only way.” she said in a sad, low voice.

With that, she concentrated for a moment, her horn glowing brightly with her magic before she opened her mouth wide. It only took a few seconds before a familiar rainbow mist flooded into the room from the city outside.

The mist came hurtling towards her as Celestia simply inhaled the magical essence. Knowing that the magic she was taking in was once her subjects made her regret the action immensely, but she knew that it was the only chance she had of matching Nightmare Moon. The rich influx of souls pouring into Celestia caused her to begin rapidly growing in size. In addition to absorbing the matter and soul’s of her subjects her horn glowed with golden light, focusing her own magic in order to amplify her growth even moreso.

Celestia cried out as her body was rocked with ecstasy. Every nerve of her body was tingling with pleasure as her marehood began to drip profusely onto her throne, soaking it with her creamy essence.

Celestia brought a hoof down between her legs and began to feverishly grind it back and forth over her thick meaty pink marehood, moaning out with increasing volume the bigger she grew.

With a flash from her horn, Celestia summoned one of her faithful Royal Guards with a flash of golden light. He was a fresh recruit, a young and handsome, earth pony stallion, and most importantly of all he was a virgin. He uttered a muffled cry of fear into her massive ass that was now covering his face, his confusion over having been teleported quickly overtaken with a mixture of shock and fear as he found himself underneath the enormous ass of his princess.

The weight of her heavy rump pressed down hard on the little stallion below her, while her little lover was luckily safeguarded with her magic from being crushed into oblivion by her great and growing weight.

Nonetheless, the stallion did let out a little hiss of pain, the keyword being little. Her body inflicted slight pain on his small form despite the magic protecting him, but not to the point it would become unbearable. It was a fine line between pain and pleasure. Celestia could dominate the little stallion and anyone else without fear of truly hurting them.

No matter how big and heavy she would become over them, she would make sure that no harm befell her little ponies.

“Shh little one.” she spoke in a soft motherly voice. “Your Princess needs your love. Can you give that to me, dear?”

Celestia giggled hearing the stallion telepathically scream ‘Yes!” into her mind, his mouth of course was too compressed against her fat ass flesh for him to talk.

With that Celestia's horn once again shone with golden light before his cock became wrapped in Celestia’s horn’s magical aura. From there she gently guided his cock into her loving marehood.

Celestia giggled upon hearing the stallion below utter a series of muffled moans and grunts of pleasure into her ass upon feeling his cock enter her marehood. She soon found herself moaning both from the nice feeling of the stallion’s cock entering her despite its relatively small size, and the constant nerve stimulation her continuous growth brought.

The stallion’s body was trembling like crazy as if he was having an electric shock. He frantically thrust his cock upward into her marehood, trying in vain to reach deeper into her.

Her powerful, loving marehood squeezed down hard upon his shaft. His penis made its way to nearly her deepest barrier. However due to her growth, the sheer length of Celestia’s birth canal meant he was no longer able to reach fully into her. His cock was by no means small, it must have been at least twenty inches long, and quite thick, an impressive and intimidating length for any normal sized mare, but Celestia even at her original height was much taller than a normal mare, and with her height continuously increasing, he became smaller and smaller within her.

Nevertheless Celestia loved the feeling of the size difference between them, which continued becoming greater and greater by each passing second. It didn't matter that his penis wasn't adequate for her. It's increasingly small size for her growing body still turned her on by the pure feeling of its shrinking within her.

She even showed him with magical aid just how far his cock reached into her. She heard the stallion below her utter a muffled sad whine into her ass upon seeing that his cock was not fully embedded into her.

“Not to worry, dear. No stallion has a big enough penis for me now.” she said softly, shaking her ass slightly. “Plus, I always found little penises cute even before I began growing bigger.”

Celestia giggled, hearing the stallion below grunt in pleasure as he began to slobber on her ass. He licked, kissed and chewed on her thick, bubbly, soft fleshy ass, paying special attention to her puffy pink ponut. She could feel his hooves tenderly kneading her buttcheeks like a thick dough, by rubbing and working them all over, stretching his little hooves out as far as he could reach.

“Yes! Love your princess’s big fat ass!” she boomed, her powerful voice echoing in her throne room. “My ass will keep getting bigger and fatter for you.”

Celestia’s marehood flooded him with a thick tide of her creamy marecum, flowing down upon the stallion below her.

He licked up her creamy essence with gusto, moaning in bliss at the wonderful sweet taste of it. Her divine essence tasted like sweet buttercream, just like what she loved to put on her cakes.

Celestia lifted her ass off him by several inches before slamming down upon him with an earth shattering boom. The cute little stallion below her was a little winded at the sudden impact and slightly bruised, but otherwise fine. Her throne below her on the other hand had cracked upon impact when her immensely heavy ass slammed down upon it.

Celestia however continued to bounce her big fat rump up and down upon the little stallion below her. She slammed down on him with increasing force as her rump continued to expand and balloon outward around him.

She moaned aloud, loving the feel of the cute’s stallion’s cock as it continued to feel smaller and smaller inside her. Becoming more inadequate by each passing second as she continued to ride her small, insignificant subject without reprieve.

The throne room was filled with the sounds of heavy slapping and creaking as her ass continued to slam up and down upon him, her throne meanwhile creaking and cracking with each impact of her enormous ass, the once strong and proud structure where she had only this morning carried out her courtly duties was now being reduced to a crumbling mess beneath her ass.

Celestia licked her lips in anticipation, feeling the near point of him slipping out of her vagina. It was cute and sexy at the same time to feel herself dominating the little stallion below with a rough and gentle way at the same time by her air ballooning ass over him becoming bigger and heavier over him.

A rush of marecum accompanied his penis slipping out of her marehood. His cock came to rest against her right butt cheek with a delightful sound of flesh slapping against flesh.

Celestia giggled and then began to grind her ass back and forth over him as if she was a non-lethal steamroller. Celestia’s mane swung back and forth freely and the sound of flesh slapping against flesh resumed as she used her massive ass to relentlessly slam it up and down upon the little stallion below her as his cock was squeezed between the thick, wide canyon of her plump buttcheeks. The warmth and softness of her fleshy cheeks rubbed his cock as she moved back and forth over him relentlessly.

The canyon gap of her cheeks between her marehood and asshole was now like a queen sized mattress. His cock was sandwiched between said cheeks, smothering it with wonderful softness and warmth.

There became less and less room in the throne room as the cheeks of Celestia's ass began to press against the very walls themselves, her ass showing no signs of ceasing its seemingly unstoppable growth.

Dust and debris began to fall from the ceiling. The stallion below her could not contain himself a moment longer, and letting out a muffled cry of ecstasy he came between the fat cheeks of her ass.

Spurt after spurt of thick creamy stallion spunk splattered between Celestia's thick asscheeks as she moaned aloud and found herself blasting globs of her creamy marecum upon the little stallion below her as she too gave in to her pleasure. The little stallion finding himself drowned in gallons of creamy, sweet, buttercream tasting liquid.

Celestia's sun cutie marks glowed with blinding light as her growth became empowered by a virgin's love and physical essence.

With that Celestia's head burst through the ceiling and her rump expanded outward, destroying the walls of her castle in one magnificent display of power.

Celestia allowed the stallion under her massive ass to enjoy a brief afterglow before she turned him into the same rainbow mist her other subjects had been transformed into and brought his soul safely within her body.

“Next time my rump shall be even bigger for you, little one. It shall be so big your mortal mind won’t be able to even conceive the size of its greatness.” she said softly.

In the back of her mind Celestia was a little worried that she was going mad with power with her growth. But she had no time to dwell on such matters, not when she had to defeat Nightmare Moon!

Celestia, now without worry of stepping on any of her subjects, began walking across the city of Canterlot, which was now barren of anyone aside from herself as her subjects were now safely inside her.

Her mighty hooves created deep craters in the ground each time they impacted, destroying everything in their path and creating dust storms with each step.

As she walked her marehood poured a continuous stream of thick creamy fluid down the great canyon of her ass cheeks. Her creamy essence created a white milky river below her as she continued on her path.

The more steps she took, the greater the craters became as her hooves rapidly widened with every passing second. Celestia's magic increased many times over as she found herself with her head breaching above the clouds.

She was able to walk over rural areas without fear of harming anyone. In fact, she deliberately stepped on a crowd of fleeing refugees from Ponyville. Her little subjects screamed in terror as her hoof slammed down upon them.

However her hoof, rather than crush them, merely turned them into a rainbow mist upon impact. They didn’t add too significant an increase of mass to her size, but she was glad they were safe regardless. She smiled as she heard the souls of her subjects thanking her for sparing them.

Over the ruins of what once was Ponyville, Nightmare Moon stood. Her front right hoof alone was wide enough to cover the entire town under it.

She now stood at a similar size to Celestia, perhaps only about 50 feet taller or so. Their heads were both now above the clouds and quickly rising still. It would not be very long until their heads began reaching the lower atmosphere at their current growth rate.

Below them their hooves sank into the planet’s mantle. Harmless seas of lava splashed against their hooves as a flood of rainbow mist of every living thing was rising into the sky with them, and found its way flowing into each of their respective mouths.

The marehoods of both Celestia and Nightmare Moon poured out their creamy essence in a deluge from the heavens to the ground below. It spilled down onto the lava, causing a low hissing noise to sound out as the lava quickly mixed with their cum and turned back to stone, the scent of hardening rock and marecum wafting up from the earth below.

“All life is safely stored within us. I'm not as cold hearted as you think I am. I don’t even want to kill you anymore. The elements have tamed my dark side and I feel compassion for every living thing now, even you, my enemy.”

“What do you want then?” asked Celestia, her tone marked with uncertainty and confusion.

“To drain you of your power and make you small, back to normal size. Then I will sit on your tiny form forever, sealing it away under my cheeks as I prove once and for all that the moon truly outshines the sun! My rump shall grow to eclipse yours in every sense of the word. And every living thing in this universe will worship me. The most fortunate shall have the glory of my ass sitting upon them forever. And you will submit and be one of the eternal subjects under my glorious ass. The night shall last forever, under the warm embrace of my ever growing, magnificent cheeks over them. This very universe itself will one day no longer be able to contain the sheer magnitude of my rump’s growth, I shall expand into other realms of existence beyond our universe and gain new subjects to sit upon.”

“No! I won’t allow you to have a bigger rump than me! Nopony has a bigger rump than Princess Celestia!” she roared, her eyes glowing orange with anger for a brief moment.

“Then let our battle begin!” boomed the Dark Mare.

With that Nightmare Moon flew off from the planet. Picking up speed as she flew towards the moon, quickly reaching her destination before landing upon its north pole. Her heavy hooves dug deep into the satellite’s crust, exposing the cold rock below.

“Here lies my former prison, a monument of my hatred for you! And I shall use my hatred to fuel a force for good. A great vestige of my power lies within my moon. I have made the place of my banishment my own, and it shall now forever be mine.”

Dark purple magical energy flowed out of the moon. Nightmare Moon moaned aloud as the growth flowed through her. Celestia looked upward, as the moon's light shone brightly, before starting to fade into a crimson red. Within mere seconds she had doubled in size, making her as large as the Blood Moon she stood upon.

Celestia’s horn glowed brightly, as the sun rose above the horizon, bathing her in its light, as she turned away from it to glance at her sister, however Nightmare moon swiftly spread her wings and dove towards her sister, her horn glowing in fury.

Celestia braced herself, expecting a magical blast, but instead she felt a great shadow being cast upon her back.

“Wait! Nightmare moon is in front of me, what could…”

When she turned around she saw the dark silhouette of the moon slowly covering the bright circle of her Sun.

Celestia flapped her wings and took flight, with great speed she dove upon Nightmare Moon, or at least she attempted to.

Nightmare Moon with a half-hearted dismissive swipe of her hoof sent Celestia hurtling back to Equis. The sudden cry of pain from Celestia made Nightmare Moon’s mouth form an ‘O’ shape.

“Curse these elements!” she exclaimed with anger, before her tone softened as she spoke once more. “Celestia? Are you alright? Please let me heal you.” said Nightmare Moon in a concerned voice.

Celestia felt very confused upon feeling the healing spell Nightmare Moon was casting on her begin to take effect. “You...You healed me?”

“Celestia…. I-I..” she began softly before her voice shifted into a dark, bitter tone.

”Don't mistake this morsel of compassion for you for love. I still wish to bury you beneath my ass! I just don’t want you dead for that. Your punishment will be eternal servitude, paying reverence beneath my almighty rump!” Nightmare Moon said, turning from Celestia as she began monologuing.

Celestia did not reply, deciding instead to make a tactical retreat while she was busy speaking. She could not take on Nightmare in her current state. She flew across the star filled sky towards the source of her divine power. The Sun itself.

Nightmare Moon however had discovered her ploy and gave chase, trying to stop her.

“No! I won’t let you become bigger than me!” she boomed.

But it was already too late. The Sun vanished from sight when Celestia flew directly into it, her body absorbing the celestial star and empowering her beyond anything she had previously achieved. Nightmare Moon screamed with fury as Celestia went supernova, literally, and grew in size all the while moaning aloud as the growth flowed through her.

A cosmic tidal wave of fat, white alicorn booty slammed into Nightmare Moon, sending her hurtling into the void of space. Celestia’s rump smashed into the planets, asteroids and other objects of the solar system, shattering them into space dust. The remains of the inner solar system were then subsequently wrapped in a golden glow, before fading away out of existence, reappearing in Celestia’s stomach. The dust added such an insignificant amount of growth to Celestia it wasn't really worth mentioning, but she still wished for their conservation within her body. In terms of size, Celestia was basically a red giant, and would soon surpass even that.

Celestia flared her magic, her horn glowing once more and magically pulled Nightmare Moon back. The Dark Mare trashed wildly about in an attempt to escape the grasp of Celestia’s magic but to no avail.

“Nooo!” she screamed.

Nightmare Moon blushed bitterly as she was pulled into the embrace of the much larger alicorn’s hooves. She was like a little teddy bear in comparison to her literal bigger sister.

Celestia cradled her in her hooves affectionately, rubbing her face against Nightmare Moon’s.

The Dark Mare lashed out violently, striking Celestia in the face. However, the action hurt herself more than it did Celestia. The act only hurting the Solar Goddess emotionally rather than physically.

“I wish you would return to me, my sweet little sister.” Celestia said softly, looking down at Nightmare Moon with pleading, doggy eyes.

However as she said this, Celestia let her guard down for a brief moment, loosening her magical grip on Nightmare Moon. This brief second gave her all the time she needed to escape.

Acting quickly in the brief window of time, she was able to teleport herself far away from Celestia.

This left Celestia all alone as her body expanded into the void at the edge of her solar system, her rump came crashing into the outer asteroid belt, turning them into a fine, grey powder.

Celestia opened her mouth wide as she began to pull planets, stars and other celestial bodies from nearby solar systems toward her, expanding her reach to pull in more and more matter to fuel her growth. She simply swallowed them whole, her mouth alone was bigger than most suns at this point. The living beings of these planets were turned into the same rainbow mist for her to eat. Not a single soul was harmed as she ate up the nearby solar systems.

Like a mega expanding black hole, Celestia soon devoured the galaxy around her. She and Nightmare Moon were becoming a magical singularity, bent on harvesting the known universe for its matter, but at the same time safeguarding all its life that would continue to live on inside of them.

Celestia licked her lips as she saw the supermassive black hole from the galactic core come flying toward her.

As the compressed matter of the black hole flooded into her mouth, Celestia’s eyes and sun cutie marks glowed with blinding light once more. Within mere nano-seconds, Celestia became a supermassive, galactic titan over the now much smaller galaxy below her. Her rumps cheeks shattered apart billions of planets into dust. Fortunately, every living thing in the galaxy was saved already. They were turned into a rainbow mist, said mist flooded into her mouth, but added such an insignificant amount of growth to her body, it wasn’t really worth talking about. Since, organic matter was tiny in comparison to planets and stars.

Celestia sucked up the dusty remains of the galaxy below her. She now expanded into the void beyond the galaxy’s horizon, into dark space. Her mighty horn glowed with golden light, pulling nearby galaxies toward her. A great rainbow mist containing all the souls of every living thing from said galaxies raised ahead of the galaxies. Their souls added insignificant size to Celestia, but she in good conscience could not destroy them, or any other sentient life. Every living thing within her now had immortality like she possessed. She would see to making them happy later. But for now, she was still engaged in battle.

Far away, Nightmare Moon could be seen sucking up galaxies, just like Celestia. The two cosmic alicorns grew toward one another. Galaxy, after galaxy was swallowed into the two. The galaxies from around them became minuscule as Celestia and Nightmare Moon exceeded hundreds of trillions of times their size. Even the so-called largest galaxies were but mere marbles in comparison to their size. Said ‘largest galaxies’ were only becoming more and more insignificant as time went on.

Celestia and Nightmare Moon ripped the universe asunder from all around them. Countless galaxies were sent hurtling towards their open mouths. The universe became emptier and emptier, until there was virtually nothing left but the two supermassive cosmic powered alicorns. They now floated in an empty black void that was once the universe, now with virtually nothing in it but themselves. Their bodies expanded now into the great void of nothing, a seemingly endless expanse of darkness.

While Celestia was indeed large it seemed Nightmare Moon was still significantly larger than her. She stood nearly twice her height. And the bulk of her body was significantly thicker.

Celestia grunted, gritting her teeth. She was much more powerful than she ever was before. But even with that, it didn't seem to be enough. Nightmare Moon's growth rate seemed significantly greater than her own, no matter how hard she tried.

“Hah. Both the bearer of the Elements and the Elements of Harmony themselves reside within me. They make me much stronger than you could ever hope to be. There is no hope Celestia, join me and feed me what you have eaten of this universe, and I promise you I will show you mercy.”

“Never!” declared Celestia defiantly, trying in vain to outgrow her, her horn flashing with blinding light.

“Celestia please, I truly mean it, I wish to offer you mercy.” Nightmare Moon said softly, pleading with her.

”As you know, the Elements of Harmony have given me new perspectives on things. Like you, I did not hurt any living thing in my conquest to consume this universe. Would you not rather be sat upon by my divine rump forever and ever? You were once my big sister, but now I shall be the bigger one. Won’t you like that? No more worries or concerns, no more enemies or crises to face. Merely worshipping beneath your sister’s body as we both enjoy our eternity together.”

“No, Nightmare Moon. I shall defeat you! And bring back my sister, my true sister! My rump will outmatch yours yet.”

“No! We are now the stronger one!” Nightmare Moon roared, turning around in quick succession, and presenting her absolutely gigantic backside to Celestia. “Know the power of our almighty rump. You shall be at home beneath it forever!”

Nightmare Moon laughed maniacally as the magical growth flowed through her once more. It seemed she was holding back beforehand as her growth now far outpaced Celestia at previously unseen speeds. A dark shadow loomed over the smaller, white alicorn.

Celestia felt a strange, cold, solid surface materialize from under her four hooves. She looked down to see she was standing on an invisible surface. Celestia outstretched her hooves and lay herself down on her back upon the hard floor, and awaited her fate.

Without a word, Nightmare Moon slammed her massive ass down upon the smaller alicorn, smothering her under the ever expanding, mega thickness of her flesh. Celestia found herself covered by Nightmare Moon’s right butt cheek. She could see a small part of her crescent moon cutie mark pressed against her face. Her long horn harmlessly phased through Nightmare Moon’s cheek as if it wasn't there.

“Give in, Celestia. I know you want to. Let my big, fat ever growing rump wash your worries away.”

Great warmth and softness bombarded Celestia’s senses. She was hit by the wonderful scent of Nightmare Moon’s marehood. Her dripping wet entrance poured down upon her like a neverending cosmic river. Nightmare Moon directed her reproductive liquid to gently flow around Celestia.

Celestia shuddered at the wonderful feeling of Nightmare Moon’s cum soaking her fur. She felt like she was in a warm bath. The coldness of space was leaving her, as Nightmare Moon's warm, creamy liquid gently splashed against her, surrounding her in it’s comforting embrace.

“Give in. Feed me your power. Make me even bigger and stronger.” said Nightmare Moon in a hot breathy voice, the pleasurable sensations of growth combined with the elation and joy of her victory over her sister.

Celestia made a futile struggle to lift Nightmare Moon’s almighty supermassive rump off her. Her hooves dug deeply into Nightmare Moon's succulent, soft ass cheek. The soft fat folded back like soft pizza dough from under her applied pressure.

“By all means, resist. Your pitiful resistance only makes me even stronger and grow even faster! We have forever to have fun together after all.”

Celestia began to fondle Nightmare Moon’s beautiful ass, rubbing her hooves up and down her plump cheek. She opened her mouth and began to kiss Nightmare Moon right on her crescent moon cutie mark.

The Dark Mare's cutie marks glowed with blinding light as her growth rate accelerated even faster.

“Yes. Now, submit to me! Feed me your love sister!” she moaned aloud.

Nightmare Moon’s body continued to grow out into the empty void, to the dark edges of the universe. Soon, her buttcheeks began seemingly pressing against an invisible barrier – the tangible edge of the Universe!

The very edge of the universe began to crack like glass from the immensity of her rump’s pressure, fractures slowly spreading all across the tangible edge of reality as they knew it.

“Mmmmmm! Yes! The universe is breaking. I must grow beyond this tiny place!”

The universe’s great barrier held against her almighty rump for quite some time, before ultimately shattering like glass. Now, as conventional physics dissolved under her mass, Nightmare Moon’s rump spread out into the multiverse itself. Entire parallel universes swam around her, spheres of dark containing stars and galaxies, each one about half her size. The universes, for Celestia on the other hand, were much bigger than her. She was little but a mere marble in comparison to their size.

The invisible floor under Celestia vanished, which allowed her to float away from Nightmare Moon’s rump. Nightmare Moon seemed to have forgotten Celestia existed as she was now busy chewing into a nearby universe. Nightmare Moon moaned aloud as she ate up the delicious matter of the universe, along with the souls of every living thing in the universe into her. Celestia teleported herself far away. So she could eat in peace.

Celestia began to once again focus her magic and tried to pull several universes toward her. She grunted from the effort, trying to pull the heavy weight of the universes toward her. Meanwhile, Nightmare Moon was hundreds of times bigger than the universes around her already.

Nightmare Moon with no issue was able to pull universes directly towards her. She sucked them up into her with ease to help her grow bigger.

“Celestia, I can’t wait to facesit on you again. I will be much bigger next time! So bony thin I am right now. I need to grow so much bigger for you!”

Celestia opened her mouth wide and hurriedly scoffed down a universe by compressing it into a tiny teaspoon of matter. She indeed had a monstrous growth spurt from eating it. But she could see Nightmare Moon in the distance, rapidly approaching her by growing toward her.

Celestia now found the strength to pull at least a dozen universes toward her. She ate them with gusto. Celestia moaned as growth flowed through her. She found herself much larger than the universes from all around her.

The universes around them became smaller and smaller, as the two alicorns became cosmic titans over them. Even the multiverse itself began to run out of universes to satisfy the mares seemingly never ending hunger.

Celestia was quite shocked to find that she was now a similar size to Nightmare Moon when she finally met her face to face. Their bodies pushed against one another as the multiverse began to run out of space.

Nightmare Moon looked at her with a smug grin. “I am holding back Celestia. I am much bigger than you. I just want my victory over you to be all the sweeter. It’s so much fun toying with you.”

Their rumps pressed against the very edge of the multiverse. Cracks formed upon the invisible barrier. Before, it ultimately shattered like glass like the previous barrier had.

Nightmare Moon and Celestia found themselves in the Omniverse. Here lay a seemingly endless sea of transparent spheres, each containing quadrillions of universes inside them.

Wasting no time, the two titan alicorns proceeded to devour the Omniverse. Quadrillions of multiverses flowed into their gaping maws, each individual multiverse alone caused unbelievable explosions of growth to the point it looked cartoonish.

So fast that they were growing, they soon found themselves bumping into the edge of the Omniverse itself already. Their massive bodies began to compress against the edge of existence, the soft, bubbly fat of their bodies became deeply compressed back. However, against the power of two supermassive alicorns, it ultimately shattered like glass like all other barriers before.

Nightmare Moon and Celestia now expanded into a great white, empty void. In this place… It was plain emptiness white with nothing in it. They had successfully eaten all of existence.

But yet… hidden energies were starting to compress into a single point between the two of them. Great amounts of energy were being concentrated to create another Omniverse, to replace the one that they just destroyed. Nightmare Moon and Celestia licked their lips, quite literally the fires of creation lay before them, the source of all matter in existence.

The two alicorns stared at one another with angry eyes. Then Celestia abruptly turned her head to look away, and stared out into the great white emptiness beyond. She pondered over what she should do next.

‘If I eat the Big Bang, there will be zero chance I will ever see my little sister again. The corruption of Nightmare Moon will only get stronger, and my sister will be lost forever. I have already seen sparks of my inner sister be unleashed for brief moments of time, before Nightmare Moon's anger drowned out her voice.“

She thought further.

“This fight I am having with Nightmare Moon is pointless. She is clearly a good and compassionate being. She hadn’t harmed a single living thing as we ate all of existence together. It seemed like she truly has been redeemed. She may be Nightmare Moon, but she is also Princess Luna deep inside. My little sister was always jealous of my larger backside. Maybe it’s time I let her have the bigger one for once.”

Meanwhile Nightmare Moon stared at her, wondering what Celestia was thinking. She dared not make a move, just in case she fell into a trap.

“Nightmare Moon, I give up. I shall give you my power and my size. You have proven yourself to be a kind soul. My pride and arrogance did not allow me to see that.” Celestia said, bowing her head low.

“You…. you really mean it? You are willingly submitting to me?” tears fell down Nightmare Moon’s cheeks as she spoke softly.

She shook her head trying to dismiss what she just heard. "I’m not sure I believe you. Let me be certain." she said in a skeptical tone.

Nightmare Moon with a flash from her horn scanned Celestia's mind to make sure she was telling the truth. When Nightmare Moon found out she wasn't lying it made her release a happy squeaking sound like a dog's chew toy.

"I know deep down that my little sister is still in there. I will probably never see her again. If I have no other choice, I will settle for you, Nightmare Moon." Celestia said in a low voice, looking downcast at her own hooves.

“My new, faithful subject, I will be like the sister you never had. I shall treat you with love and tenderness. A new, big sister to watch over you and keep you safe. In time, you will grow to love me even more than Princess Luna. You shall have a special place under my rump. Right under the cutie mark of my magnificent right buttcheek. I can summon forth the most handsome, gentlestallions in existence, from any species you desire. I will make sure they will give you love and tenderness. They shall hold your hoof and romantically dance with you upon our rump and treat you like the princess you are! And they will of course have a very large penis to satisfy you in bed upon our rump.”

The singularity of the Big Bang was held in place by both of their magic. Thus stopping it from exploding. The two wanted to have a talk first.

Nightmare Moon meanwhile continued her speech. “You will become my second-in-command. Despite the fact you will become a far lesser mare than me. If any stallion is cruel to you just because you have a lesser backside than me, let me know. I will not stand for them mocking you. They will be severely punished. For 1000 years they will not know the grace of my massive, ever growing ass sitting upon them for their transgression. Only I, as your big sister, have permission to belittle you as the lesser, but still beautiful mare upon our rump.”

"Thank you, Nightmare Moon. Go eat the singularity first containing the Big Bang. Show me your superiority over me. Show me how powerful you can become before you drain me of my power and size.” Celestia declared, staring up at the titanous Mare.

“I will, Celestia! I shall grow to sizes that you cannot even conceive of. You shall be a lesser, bony thin mare when compared to the glory of my supreme backside.”

Celestia teared up, looking at her own rump behind her. She dreaded the thought of it becoming smaller. “I love you Luna, my sister. I will sacrifice my own beauty for you.”

“Oh, that’s very sweet of you.” Nightmare Moon said softly, finding herself tearing up in her eyes.”But, unfortunately, your sacrifice shall be in vain. I, Nightmare Moon, am in control now over your former sister, Luna. Do not worry, I shall be a better sister than her for you. Now watch, as I attain my rightful place and become your Big Sister.”

With that Nightmare Moon pulled the Big Bang into her gaping maw, it went down her gullet and into her belly in a single gulp. She waited patiently, as these exotic cosmical energies flowed through her into the singularity, building up more, and more, and more…

Then suddenly, just as she thought she couldn’t take it anymore, her stomach rocked with a great explosion – a Big Bang, one that signified the creation of everything, including existence – puny existence, she was all that was now! In only about one nanosecond, she went relatively speaking, from the size of an atom to the size of a galaxy – and that was just the beginning! Her growth rate was stronger than ever before, now powered by the very fires of creation.

As the fires of creation’s growth flowed through her, she could be heard crying out in bliss into the void. The sheer noise of her moans would have made Celestia completely deaf had Nightmare Moon not cast protection spells on her ears.

The very moment Nightmare Moon began to expand with the power of the Big Bang inside her, Celestia had found herself lodged under Nightmare Moon’s right buttcheek, right upon her crescent moon cutie mark. The gravitational pull of Nightmare Moon’s rump basically stuck her to her ass like a magnet.

Celestia sank deeply into her soft, bubbly rear. Her body began to tremble at the wonderful feeling of soft fur and fat pressed against her. Her marehood leaked between her legs, and spilled a continuous stream of her essence upon Nightmare Moon’s ass, soaking her warm, soft fur touching against Celestia's marehood.

Celestia’s juices flowed down Nightmare Moon’s buttcheek. Her marecum would never ever reach the bottom of Nightmare Moon’s ass however due to the massive expanse of size. Celestia’s reproductive liquid flowed down like a gentle stream, while Nightmare Moon’s rump was hyper expanding, faster and faster in a continuous flow.

Tidal waves of fat raged across her rump like a stormy ocean from her unending monstrous growth spurts. The only peaceful area in the raging storm that was her buttcheeks was the place Celestia lay upon. A dark purple sphere of magical energy wrapped itself around her, ensuring she could not escape the grasp of her rump.

The beauty of Nightmare Moon’s growing ass caused Celestia to go mad with lust. With love and tenderness she began rubbing the soft, warm bubbly flesh she lay upon with her hooves. She dug in deeply into the thick layers of soft fat. Although, in reality she was only digging into an insignificant amount of the way through the ever expanding thicknesses of Nightmare Moon’s rump.

Celestia paid further homage by kissing and licking Nightmare Moon’s cheek, hoping desperately that her act would fuel Nightmare Moon’s growth even more.

“Muahahahahahaha! Yes! I grow even faster thanks to your worship!” she boomed.

Celestia was but a mere white speck within a sea of black that was her asscheek. The reverence she paid to her rump only made it grow even faster. Much faster.

Celestia’s show of affection had a substantial effect upon Nightmare Moon’s growth rate. It wasn't a mere tribute of growth. It even outpaced all the continuous big bangs inside her by far. It was… the power of Love.

“Muahahahahahaha! Yes! Love ME! Worship our divine derriere! Puny one! FEED ME your LOVE! HELP ME GROW! Faster! Stronger! BIGGER! FATTER! HEAVIER! Bow before me! My insignificant pipsqueak of a subject!” boomed Nightmare Moon in ecstasy.

Like a supermassive exploding quasar, Nightmare Moon released violent explosions of creamy white marecum into the empty white void behind her.

“This is pure bliss! I can’t get enough! MORE! MORE! MORE!” she boomed again.

Over and over, and again. The singularity inside her attempted to recreate the Omniverse with a Big Bang, it instead just fed Nightmare Moon. Nightmare Moon used her magic to increase the velocity of the explosions inside her. The Big Bang left her unharmed, it just allowed her to grow faster and faster in a seemingly never ending cycle.

“Yes! Yes! Yes! Faster! BIGGER! STRONGER! FATTER! HEAVIER!” she cried out.

On and on and on she surged in growth, the exponentially-thickening layers of fat further plushing herself, her rump cartoonishly bulging out in size, her belly struggling to process such a rich influx of mass and energy. Nightmare Moon, with the urges of a drug addict, powered up her horn, increasing her growth rate even further with her own magic on top of the Big Bang, and Celestia’s worship.

“YESSSSSS! MORE! SUCH POWER! SUCH GROWTH! I want more! I can never be BIG ENOUGH!” she demanded, her horn glowing alongside the Big Bang going on inside her belly, to fuel her growth even more, her maddening desire for growth seemingly unable to be sated.

Nightmare Moon’s magical power increased beyond any recognition, she dared believe she had the power to destroy all of existence now with just a flick of her magic. Of course, she would never do that; she wanted to outclass and overtake Celestia with the best, biggest, fattest butt in existence. Celestia’s ass was so bony thin when compared to her supreme thickness.

“I LOVE YOU! Celestia! MY LITTLE SISTER I LOVE YOU! I LOVE YOU! I LOVE YOU! Ooooooohhhhhhhhh! YES! Mmmmmmmmmmm!”

Her growth euphoria was so strong, Nightmare Moon whimpered – despite her infinite divine powers, she found herself at the mercy to her own pleasure, drunk on her own size, begging for more and more bulk to be added onto herself.

And she knew… where she could find just a little bit more matter she had not eaten outside the old Omniverse. “Celestia, it is time. Give me what you have eaten on our journey to get here in the void.” she spoke softly in a motherly tone of voice, as if she was speaking to a young foal.

“You are free to suck out my power and size. Just please be… gentle.” Celestia pleaded, in a low voice, begging for mercy.

Nightmare Moon made a sad whining sound, shocked that she had rendered the once powerful mare of Celestia into such a pathetic weakling. “Your fear wounds me deeply, Celestia. Of course, I will be gentle. I would never truly hurt you.” she said softly.

Nightmare Moon then spoke in a cold tone of voice. “I will now feed upon your insignificant mass and add nearly all of it to my own. Prepare to become even more insignificant to my size than you already are.”

Celestia felt her body weakening as her magical energy was zapped out of her mouth, and sent directly into Nightmare Moon’s cutie mark below. Her cutie mark glowed with blinding light as she fed on the matter Celestia had eaten.

Celestia looked back with teary eyes, where she saw her rump rapidly become smaller and smaller by the nanosecond.

“Don’t cry, Celestia.” Nightmare Moon spoke softly. “I shall leave you with a modestly plump backside when I’m done with you. I’m not totally heartless.”

Despite Nightmare Moon’s comforting words, she could not help but cry into Nightmare Moon’s ass, her tears, damping her fur as she felt like a lesser and lesser mare by the second.

Nightmare Moon teared up seeing Celestia in such a state. She almost had second thoughts of eating her power and size.

Almost being the key word.

“Celestia, please don’t cry. You are still a beautiful mare. Even if you are so insignificant when compared to me. You shall receive special treatment among my subjects. I will make you happy in any way I can. Just… please… stop crying… it's breaking my heart.”

Celestia became smaller and smaller until eventually she was reduced to her original size. Celestia wailed in grief as she looked at her bony thin, and frail body when compared to what she was once before.

“I’m sorry Celestia.” Nightmare Moon spoke softly, as she stared down with pity at the crying Celestia lying upon her buttcheek. “But you must know your place as my little sister. In time, you will get over the loss of your size, and embrace the warmth and softness of my rump to drown out your miseries.”

Nightmare Moon turned to look away. She could no longer stand the sight of Celestia so upset. Instead, she decided to look at the great empty white void from all around her. No matter how big and fast she grew, there didn’t seem to be an end to it.

Nightmare Moon growled at the white void in anger as the empty space seemingly mocked her by its very existence. “I will find a way to fill you, void! Nothing can escape my ever faster expanding mass!”

With that, Nightmare Moon started to rapidly multiply, creating copies of herself as if she was an asexual, single bacteria, all in an attempt to fill the great white void. Each individual clone of Nightmare Moon grew in size as well, faster and faster. Of course she would not allow the clones of herself to have a growth rate or be anywhere near bigger than the original version of herself.

Each copy of Nightmare Moon also created clones of itself, and said clones made clones of each other. She was basically creating supermassive magical nanomachines of herself. Already there were literally quadrillions of clones of Nightmare Moon. The population growth of her copies only increased faster and faster as more and more copies of herself were made.

“I wonder… if there’s anything even beyond here. Let’s try to find out, my dear Celestia.” said Nightmare Moon.

With teary eyes, Celestia looked up in awe at the sea of Nightmare Moons filling the void. The white void from where she lay was covered in blackness, all of it being quadrillions of clones of Nightmare Moon in just her local area of the void.

Nightmare Moon with magical aid showed Celestia, she was but a tiny white speck on the unbelievably massive cheek of Nightmare Moon’s ass. She would never reach the end of her rump even with light speed. For even light speed was slow in comparison to the expansion speed of her rump.

The copies of Nightmare Moon began to make out with each other and fondle each other's asses with love. This only added to their expansion speed with each grope, with each squeeze and caress of flesh shared between them.

“You…. you are…. so beautiful. I-I…. I don’t know why I ever resisted before.” said Celestia, her voice breathless at the site of an orgy of flesh happening before her eyes which went beyond even cosmic levels of understanding.

“All is forgiven Celestia. You were but a naive foal. Your kind words mean so much to me. I shall be extra gentle with you when I sit on your miniscule form. But for now, let me show you one part of my body.”

Celestia found herself floating, being gently carried by Nightmare Moon’s magic. With great speed Nightmare Moon took Celestia for a fantastic view by placing her down at the cliff’s edge of her rump’s cheek.

Celestia looked down at the seemingly dark abyss that was the grand canyon of her buttcheeks. She looked across the great expanse to try to see her other cheek, but it didn’t seem to be there.

“I can't see your other ass cheek, Nightmare Moon.”

“My left buttcheek is there, Celestia. Your small eyes just cannot see even 0.1% the way across my butt’s canyon. As I grow bigger so does my cheeks become further away from the other. And you will never get to see it without my help. I see both of my cheeks fine. I see you, as a tiny white speck in an endless, ever growing sea of black that is my magnificent rump.”

“Can you still press your buttcheeks together to show me?”

“Yes. Of course. Let me show you my beautiful, left buttcheek.”

At first Celestia saw nothing. Until a great black, tidal wave of alicorn booty came closing in fast. Nightmare Moon’s cosmic cheeks slapped against one another with the sound of flesh slapping against flesh. The true noise was much louder, but Nightmare Moon had the grace to protect Celestia’s ears.

The resulting shockwave however sent Celestia hurtling out into the void at tremendous speed. The sea of Nightmare Moon clones stopped Celestia being truly separated from the original Nightmare Moon. She just ended up landing softly on one of the many clones’ rumps.

Celestia's body became encased in an azure glow. Nightmare Moon magically pulled her back to her, and placed her back on the cliff’s edge of her right cheek.

“Sorry about that. It was cruel of me to send you away from the warm embrace of my massive, ever growing rump. You were on a small, pitiful lesser mare. Even if you put all the clones of myself together, they are still not even 01.% the size of me. I did that by accident. Can you forgive me?”

“Of course I forgive you, Nightmare Moon.”

“Good. Because now it is time for my ultimate triumph over you.”

With a flash, she found herself lying on her back upon a cold, invisible surface. Celestia shivered as she no longer had the great thickness of her former body to protect herself from the cold.

“Brrrrr. I’m cold, Nightmare Moon. Please, I need your rump to sit on me.” she pleaded.

A great unending mass of dark purple and white slowly descended down to Celestia. It was the borders edge of her inner cutie mark. Where her dark purple blotches, to her white crescent moon had met.

“Do not fear, sister. The warmth of my rump descends upon you! It shall drown out the cold!” Nightmare Moon boomed.

Celestia teared up, her mouth forming an ‘O’ shape as she stared up in awe at a small part of Nightmare Moon’s all powerful rump. She could only see a small part of her ass, for her butt was the undisputed largest, most beautiful butt in all existence. Her own rump, was bony thin and frail before the majesty of Nightmare Moon's glorious rump.

There came a loud bang, louder than the continuous big bangs happening within her body when Nightmare Moon’s ass made landfall upon Celestia. It would have completely deafened Celestia, if Nightmare Moon had not protected her ears with magic.

Princess Celestia hissed in pain from the incredible weight pressing down upon her. Her body flailed like a fish out of water from the warmth and softness of Nightmare Moon’s almighty rump upon her. She felt compelled to kiss Nightmare Moon, and pressed her lips upon her cutie mark and began to passionately kiss her divine rear with a well defined smooching sound.

Celestia’s ears perked from hearing a very unusual reaction from Nightmare Moon from this simple kiss. She screamed as if she was in pain.

“No… I am losing control!” Nightmare Moon screamed.

“Be gone!” came a familiar voice, Celestia heard a thousand years ago.

“Noooo!” screamed Nightmare Moon’s voice.

The dark purple border of Nightmare Moon’s changed into a black color when it met her white crescent moon.

“Luna… is that you? Have you returned to me?”

“Yes, it is I, my sweet sister. Your heroic sacrifice of your beauty has defeated Nightmare Moon, through your act of love I gained the strength to overpower her. She is lodged safely within me. She will no longer torment you.”

Celestia stared at the still breathtaking expanse of her now returned sister’s ass for several moments, processing the fact that Nightmare Moon was gone once and for all, before speaking up in a reserved tone.

“Please, release her Luna.”

Out of all the possible words to come out of Celestia’s mouth, Luna had not been expecting that to be the first thing she would say upon her return.

“What? No! She is a cruel mare. She belittled you at your reduced size. I shall help you restore your beauty by giving you a big body with a large backside. You deserve as much.”

“But Nightmare Moon isn’t evil anymore, I know this to be true. Please release her.” Celestia pleaded, before she blushed slightly, looking down at the ground of Luna’s flesh and uttering in a quiet tone that her sister still heard clearly.

“Besides...I...I kind of like her belittling me in a strange way.”

Nightmare Moon’s voice cried out from within Luna, she and Celestia hearing her words in their minds. “Please release us! Just think how much sexier it would be for the three of us to share the void together!”

Luna sighed deeply after several seconds of contemplation, which wasn’t helped by the pleading ‘puppy dog’ expression on Celestia’s face as she finally relented.

“Don’t make me regret this.” she declared wearily before her horn shone brightly with her magic.

For a moment, nothing happened. Until a great sea of purple and white came speeding toward Celestia. By Luna’s perspective it was merely the super cosmic giantess of Nightmare Moon pushing her buttcheek against her own. Which resulted in Celestia being sandwiched between the two supermassive alicorn butts, at their cutie marks.

Luna frowned, as she saw that Nightmare Moon was significantly larger than her. Her growth rate was out pacing hers by quadrillions of feet or so. She felt like a mere foal standing next to a mountain in terms of size.

“Jealous, are you? It only makes me grow faster! Much faster!” said Nightmare Moon in a mocking tone.

Nightmare Moon moaned aloud as newfound growth flowed through her, making her eyes flutter in sexual pleasure at the rush of power she felt from Luna’s emotions flowing through her via their shared bond, even being physically separated did not sever the connection to the two held.

"Mmmmmm. Oh yes, Luna. Feed me your envy. Make me grow bigger faster. Make me even more beautiful."

The size difference increased dramatically between the two. Luna soon found herself to be little but a dark blue speck on Nightmare Moon’s rump. The size difference was even more ridiculous when one compared the size of Celestia to Nightmare Moon.

“My body cannot be comprehended in size.” said Nightmare Moon with pride.“And it's all thanks to you, Celestia. Your willingness to forgive me has increased my power and growth rate beyond all measure. To give you some idea of how fast I am growing, the fires of creation feeding my growth are slow and insignificant to what you have done for me. Now, is there anything you wish I could do in return for you?”

“Is there any chance I could become bigger than you?” Celestia asked meekly.

“Unfortunately not. You will have to live with being a lesser mare of my stature. Somehow I cannot even make that possible. I can however make you very big. Much bigger than your sister, Luna.”

“Let me ask her first.” Celestia said before she took a deep breath.“Luna, I don’t want to lose you again. Should I reject Nightmare’s offer to make me bigger than you?”

“You won’t lose me, Celestia. Not ever again. Allow Nightmare Moon to make you much bigger than me. I am your little sister after all. I want to be the smaller one among you. I promise, I will not be jealous of you, not any more, even if you grow bigger than me. Your heroic sacrifice, earned you a bigger rump than me.”

Upon hearing her sister's words, she smiled brightly before turning back to Nightmare Moon. “Hit it. Nightmare Moon. Make me beautiful again.” shouted Celestia.

“Anything for you, my little sister.” said Nightmare Moon, flashing her horn with blinding light.

There came a low rumbling before Celestia skyrocketed into the air with a loud moan. Within mere moments, Princess Luna was but a mere speck of dark purple against Princess Celestia’s sun cutie mark. However, Celestia was but a mere speck of white against Nightmare Moon’s cutie mark.

“I guess, we better recreate existence for our little subjects to live on. I don’t think everyone wants to live inside me forever, or upon our rump.” said Nightmare Moon.

“There’s no rush to do so, my other half. All life within us has immortality just like us.” spoke Luna’s voice.

“I guess so. Don’t you want a massive magnificent rump like Celestia’s to facesit on them? I can even increase your sexual sensitivity so you can perceive the tiny, cute penises pressed against your ass from our little subjects.” Nightmare Moon said, while casually bouncing her massive rump against an invisible wall. Upon said wall countless beings from many alien races were stuck to it.

Nightmare Moon continued. “It's so cute hearing them squirm underneath you. I can even show them some idea how large I am compared to them. I often have to magically fix their minds since I kind of drive them insane a lot of the time by doing that.”

“Will you miss a handsome stallion filling you with his penis? Because I will.” Luna asked.

“Mmmmmm! Yes! Cum upon me, my little pipsqueaks. Fuel my growth even more with your love.” Nightmare Moon said in a hot breathy voice, grinding her ass back and forth, steam rolling her massive ass over the little beings underneath her.

“We can always just make a small avatar of ourselves if we wanted that.” spoke Celestia, clearly having thought ahead and recalling the last stallion’s cock she had experienced before leaving Canterlot.

“True.” said Nightmare Moon.”But I, personally find the sensation of growing bigger and bigger over a little lover much more sexy, than traditional sex. Speaking of which, would you like to have your face sat upon by me? There’s more than enough room under my ever growing ass for the two of you.”

“Yes. And leave us at your mercy. Strip us of our power so we can’t escape. And make us normal sized. I trust you, not to abuse your power. But I expect you to mock us and belittle our small bodies underneath your magnificent rump.”

“Yes. I too would like to experience this. Celestia trusts you, and so do I.” said Luna as she nodded in her sister's direction.

Nightmare Moon whimpered, tears falling down her cheeks and as she spoke softly. “Once more, your trust in me has increased my growth rate even further. I am feeding off both Luna's trust and jealousy at the same time. Thank you, my little sister."

Luna growled angrily."You're welcome. I guess."

Nightmare Moon giggled at Luna's jealousy."If at any point, you wish to have massive bodies again, and be released from under our rump just ask.” she said softly, before shifting into a mocking tone.“But for now, know what it feels like to be so insignificant under our magnificent rump, my cute little pipsqueaks.”

Celestia and Luna found themselves instantly stripped of their massive sizes, and their backs glued against an invisible, cold wall. They tested their horns' magic, only to find them to spark uselessly, leaving them at Nightmare Moon’s mercy completely.

The two mares leaned in for a passionate kiss, their tongues entering one another’s mouths. Celestia and Luna moaned in bliss as they shared this moment together. Above them Nightmare Moon’s massive ass slowly descended, to enhance this magical moment even more.

“I love you, Celestia and Luna! Oh this is so romantic! Growth is flowing through me, more powerful than ever.” boomed Nightmare Moon as her cutie marks glowed with blinding light, and her rump jiggled like crazy from tidal waves of growth flooding into it.

Nightmare Moon smiled, hearing their voice replying back with ‘I love you too’. At long last, she felt no longer filled with rage. She was a kind, good mare, who wanted to bring happiness to all. And keep growing bigger and bigger, at a faster and faster rate forever and ever for all eternity.

The End