Execution
The crystal palace was quiet at night. Any sound would be noticed by the guards. That wouldn't be an issue for her.
Sunset Shimmer snuck through the halls with ease. Equestrian security hadn't gotten any better since she'd been gone, clearly. There weren't many guards patrolling and the few there were effortlessly avoided with her powerful magical abilities. She knew enough stealth spells to make even the most powerful Changeling Queen gawk. If her magic somehow failed, which was near impossible, the orange pony wore a heavy cloak that obscured most of her form.
After some time of wondering, the unicorn mare finally found the guest rooms. Each room had a label next to it indicating who was staying there. Moving at a slow pace, the disgraced student read each plaque as she passed by. She eventually stopped in front of the door labeled "Princess Twilight Sparkle". A smirk plastered itself across her lips. It was almost too easy.
If Sunset had been a normal pony, her plan would have failed. But she was Sunset Shimmer, former personal student of Princess Celestia. She had plenty of skills at her disposal. Forbidden knowledge was stored inside her head. She was the most powerful unicorn in Equestria. She could handle herself just fine.
Sunset carefully opened the doors trying to make as little noise as possible. She imminently noticed the massive bed at the far end of the room. An evil grin spread on her face as she saw a certain purple alicorn snoozing on the mattress. The rest of the space seemed mostly empty. Still, the fiery mare needed a good look at the place to check for dangers. Wouldn't do to come this far just to fail. Cyan eyes scanned the room.
On a small circular crystal end table on the left of the bed, next to a lamp, sat her prize. The Element of Magic. There was a large dresser with a mirror against the right most wall. Almost directly to her side was a small petbed, on which slept a green and purple infantile Dragon.
Problems were bound to arise with the little Drake so close to the door. Something had to be done. The idea of "disappearing" it existed for not but a moment before she shot it down with a thousand mental bullets. The thing was just a child. Nothing in the world could make her harm such young eyes. With her own foalhood having been so horrific, the thought of inflicting that level of trauma on another made her feel sick. Instead, she merely moved the small bed across the room.
Now that all potential hazards had been taken care of, Sunset turned to her real quarry. Or quarries.
Princess Twilight looked peaceful as she slept. The mare let out cute snores rhythmically. Sunset felt herself get angrier. Why did this purple bitchcorn get to live such a happy life while she gets stuck in monkeyland! It just wasn't fair! And the fiery girl planned to make it right.
Reaching into her saddlebags, Sunset pulled out a anti-magic ring. The orange unicorn gently slipped it over Twilight's horn, where she anchored it in place. With a glow of her own horn, Sunset carefully wrapped the sleeping mare in the blanket she slept under. After she was confident nopony would be able to tell what was wrapped up, she lifted her into the air. She nabbed the Element of Magic just before she trotted out the room, stuffing the relic into her saddle bags.
She knew how the nobles unpersonned ponies they didn't like. Blackmailing, leaking secrets, and generally ruining their public image. The public shaming worked well enough, but it was too kind for her tastes. Those who crossed her should suffer. Instead, she found her own way to deal with annoyances. It had been a long time since she had done it, but she had done it enough that the process stuck in her mind even decades later. Carrying it out should be little trouble if any.
The orange unicorn used more caution then her previous trek through the crystalline palace. Sunset had been alone before. Now that she had cargo, there was an element of challenge in the equation. Not much, mind, but enough to issues. The mare couldn't maintain most of the stealth spells she had been using on both herself and an foreign body. So she had to be more sparing with her magic.
She was about halfway back before any signs of trouble arose.
"Hey, did you hear something?"
She froze.
"Naw."
"But I swore-"
"It's just the newbie nerves getting to ya. Don't worry 'bout it. And even if it was something, chances are we couldn't do much about it."
"But sir, there could be-"
"Don't worry about it."
Sunset realized she was just standing there as the voices became louder. Thinking quickly, she cast an invisibility spell on herself and hugged the nearest wall. Not moments later did a pair of crystal guards round the corner. If she had been paying closer attention, Sunset would have recognized one of them.
Their conversation went on, but the orange mare didn't really care for what they were talking about. She was too concerned with not getting caught. The situation lasted for but a minute, but it felt so much longer to her. Eventually their voices faded off into the distance. Only when she was absolutely certain they were gone did Sunset continue on her way.
The rest of her journey was thankfully uneventful. No other other encounters or slip-ups.
She shut the sole door to the room. Then locked it, both with the physical lock and with an advanced arcane seal. To top it off, she used a large box to block the door. The room was briefly enveloped in a red glow of magic as several spells were cast upon it. The fiery unicorn took a minute to search the room, just in case anypony had entered while she was gone. With the safeguards in place and the room free of intruders, she turned to the sleeping alicorn.
As stated before, back when Sunset had been Celestia's student, she developed an efficient method to rid herself of unwanted persons. Unlike the one the nobles used, hers was much more... permanent. It was a brutal act that left no evidence, no body, and no witnesses behind. She ate her target whole.
It hadn't been hard for the calculating mare to figure out. A spell here, an anatomical change there, one abandoned room, and the deed was done. The process quickly became foal's play for her magical abilities. Not only was there no trance of her victim, but it made her already amazing body that much more so. Plus it was a free meal and meat tasted great, it turns out.
It was finally time for her to again rid herself of a thorn.
Even though the unicorn just locked up, she still don't feel like it was safe. It couldn't be this easy. Could it? A wave of paranoia washed over Sunset. It wouldn't hurt to do a quick check, right?
She checked that the door was locked, sealed, and barred. Made sure her silencing spells was intact. Recast the sleeping spell. Checked the anti-magic ring was working. Double checked that she was alone. She couldn't allow herself to be caught or interrupted. She HAD to savor this moment of sweet, sweet, revenge as much as possible. Everything had to be perfect.
And it was.
With evil grin, Sunset opened her mouth far wider then any pony should be able to. She could easily down a buffalo if she really wanted to. This small mare was not a challenge. Sunset lifted her quarry in front of her. Drool lined her maw as her body anticipated partaking in her forgotten pastime.
She pushed Twilight's head into her own. Waves of flavor immediately assaulted her. The familiar taste of pony flesh caused the fiery mare to moan in delight. It had been too long since her last pony snack. Once she ruled Equestria, she had to do this way more often.
Once the princess's face was nice and slick, Sunset pushed her into the back of her mouth and swallowed. Her throat bulged with the form of her resting prey. The feeling of such a big mass of meat within her after going so long without her forced a shutter from her equine form. The orange unicorn savored the moment before return her focus to the rest of her meal.
Consuming Twilight was a slow process. Not for any difficultly with the task, but purely because the orange pony intended to squeeze every last drop of enjoyment she could. With every taste, feeling, and swallow, Sunset reveled in her alicorn meal.
The sleeping purple pony was shoulder deep inside her orange devourer when her head found the stomach sphincter. One loud glk and she was welcomed inside the flesh prison. Another shutter ran through Sunset as she felt her belly begin to fill with mare meat. She swallowed again, pinning Twilight's forelegs to her barrel.
Sunset's neck bulged as the torso of her meal started to enter it. Purple wings brushed passed her lips, the soft feathers providing another layer of flavor to the orange mare's pony meal. With each gulp, her throat pulsed and swelled, her belly grew, and her moans became louder and more intense. Twilight's back legs moved slightly, the unconscious alicorn unknowingly aiding in her descent as they were pinned against her tummy alongside her fores, turning herself into a loaf of delicious pony flesh.
The base of Twilight's plump plot pressed against Sunset's lips. Having been one that preferred indoor activities such as reading and studying, her posterior was jiggly and thick with fat. Being good friends with a excitable pink baker only made the problem much, much worse. So when her fatty rump was enveloped by those orange jaw, it was as if the gates of flavor heaven had opened inside her mouth.
Were it not for the silencing spell, the unicorn's enjoyment would have awoken the whole castle.
Sunset went to town on the juicy plot. She spent minutes savoring it, reveling in each wobbling jiggle, the soft texture of Twilight's backside like silk upon her rough tongue. Not one bit of fur was spared from the onslaught of saliva. Even the alicorn's teats got a spit bath, the assault causing them to leak with milk, the flavor almost lost to the mare ingesting her. Only her flower and exit were left untouched by the probing organ.
Twilight's ass sank very slowly into her throat. Eventually, Sunset closed her mouth, lips and teeth sealing the princess-turned-meat to her doom. Only a multi-hued lavender tail dangled from her maw. With a slurp, it too was yanked inside.
After a half minute more of tasting, Sunset Shimmer took a final loud gulp, her neck swelling as the last of her meal was send down it. Soon, Twilight was fully packed within her stomach. Her gut tightened around it's prize as it settled, creating a skintight seal around the sleeping alicorn. Every curve of the Princess could be seen, albeit under a blanket of orange fur. Thanks to Sunset's height, her engorged belly didn't even touch the floor, hovering 5 inches above it.
A good minute went by where the orange mare was still as she recovered from her massive treat. It had been so long.
Air blasted out of Sunset in a loud belch that awoke her.
She looked at her gut, tracing it's soft movement as it attempted to break down it's occupant. It couldn't without her spell, but she intended to enjoy this. She wanted to savor this.
Minutes went by as she relished the feeling of fullness. Her stomach gurgled and groaned. Orange hoofs gently caressed the stretched skin, the pleasant feeling sending a shiver through her. She occasionally burped, giving her another taste of maremeat. It was a peacefully moment.
Having enjoyed her victory enough, Sunset decided it was time to wrap things up.
"Well Princess, it's been fun" Sunset smirked, "But I have places to be. I guess you do too, even if it's my tits, ass and toilet."
Sunset's horn glowed red, a similar glow encasing her belly, "So long Princess Twilight Sparkle. Hope you enjoyed your personal tour of my insides! Please leave a ti-YESSSSS!"
Suddenly, a thunderous cacophony of digestive noises rang out from within as her spell took effect. Her body shivered in bliss as it revered up like an engine to absorb the hunk of meat formerly known as Twilight Sparkle, Hero Princess of Equestria. The mare in question remained snoring away, Sunset's spell too powerful to break even against the roars of digestion.
With a groaning gurgle, her stomach was filled with acid, making the form inside disappear into the ball of orange fur. The spherical gut now rested on the floor, sloshing adding to the collection of sounds. All the air that previously filled her digestive sack rushed up Sunset's throat along with some feathers that had separated from Twilight on the way down, causing her to loose a massive belch.
Her belly gurgled as the main event started up. First came the fur, hair and feathers which practically melted off the purple mare. Next was her skin, boiling right off. Now Twilight's organs and bones began to spill out, the mare herself very much dead at this point. The whole time, Sunset was lost in a world of pure pleasure.
The prodigious unicorn's belly slowly began to shrink with the sounds of cracking bones. As it did, other places on Sunset's body began to grow. Her already sizable rump grew noticeably bigger. The mare's large teats swelled with fat and milk beneath her. Boney nubs protruded from her sides, slowly spurting into a pair of orange wings. She even stood a little taller.
In a little over 6 minutes, the princess of friendship had been completely digested, leaving behind a slightly fatter orange alicorn. What bits Sunset's body had rejected filled her colon as a mass of solid brown tubes, with not even her bones surviving the process.
Once again, the now alicorn mare was still lost in a world of bliss for some time. Her nethers dripped with juices from her total domination of the mare who had replaced her as the Sun Princess's student. The pony's fur was matted with sweat, mare-cum leaking down her hind legs making them sticky.
Snapping out of her trance, Sunset hurried over to the mirror. This had been her first alicorn, so she was curious if that changed anything. She gasped the moment she saw her new appendages.
She had wings. After coveting them for so long, they were hers. She starting giggling like a little filly. Take that, Celestia! After admiring herself for a bit, Sunset refocused on her plan.
Now that she had taken care of her competition and stolen one of the worlds most potent sources of magical power, it was time to take her plan to phase 2. The conquering of Earth.
Equestria was still her ultimate goal, but everything here had some form of protection against magic. Sure, that protection wouldn't hold against her newfound might, but it made room for failure. If she could get the might of the Humans behind, what with everything they made far, far surpassing Equestria in technology, innovation, weaponry, anything but magic really, she could have Equestria in her palm within an hour or two. Not much magic could do against nukes. Princess Celestia would be forced to call Sunset her daughter at last. If not, then she gets to have a lovely lunch. Win-win.
Before all that, however, she had a deposit to make. Twilight's remains were putting pressure on her exit as the former mare desperately wanted out. Sunset moved towards the portal, not wanting to make a mess here. The fiery alicorn had done the math long ago that ponies were much smaller humans. The portal had a clear pattern to what it transformed, so she was confident that she could discreetly dump her meal with time to spare.
After a quick admiration of the new additions to her figure in the mirror, the soon-to-be world conqueror stepped into the portal.