Equestria.

Luna sat there, shocked. "B-b-but... Tis impossible! The Nightmare was vanquished!"

Sitting across from her Celestia sadly shook her head. "No. The Elements were not fully in sync yet, and were only able to banish it to the void between worlds, stripped of most of its power."

Luna was trying her hardest to not start running around like a filly with her mane on fire. "That doesn't explain how it was able to take a corporeal form without a host!"

Celestia sighed. "That's the worst part, sister, it dragged some poor soul across the void to transform into a suitable host, and considering that it lacks our levels of power, it has most likely been irreversibly enslaved to the Nightmares will!" Her facade of calmness shattered, leaving a scowl on her face. "Gather the Bearers, we must make sure the Nightmare is truly destroyed this time!"

Luna could only steel her resolve for what was to come.

Everfree Forest, abandoned castle, throne room

Even after the Nightmares banishment, wildlife had avoided these ruins due to the massive amounts of dark energy that even to this day, hung in the air like a miasma. Said miasma had begun gathering, gravitation into a vortex of raw, unadulterated, dark power. With the sound of what could only be described as the fabric of reality being simultaneously pierced and torn, a body fell out of the vortex, a human males body, to be precise.

It didn't remain that way for long...

The miasma slowly began to seep into the body, as it did, his face began to change, to stretch, until it became a muzzle, meanwhile, his ears began shifting upwards reshaping themselves to better pick up sounds. His canines elongated, now resembling fangs, while his neck elongated, becoming swan-like. His limbs began to grow with sicking pops as bones and joints were rearranged, while his fingers and toes receded into large lumps of keriten, or hooves as they were more commonly called. With a loud rip, wings, leathery and bloody, emerged from his back, while new nerves began to form near the end of his spine, before it extended slightly forming the beginning of a tail, as ethereal hairs began sprout from both this and his head, whereas the the hair that began growing over the rest of his body, was colored a black that could only be described as so empty, that the color black should not even exist as a concept. His brain was subtly shifted, rewiring itself to integrate these changes, as well as a few more. With the sound of an over ripened pumpkin being impaled, a horn, long ad spiraled, erupted from his head.

Unseen to outside observers, several other changes began taking place. Such as beneath his eyelids, where his irises began to narrow, becoming long and catlike. Unfortunately for him, there was one more change that took place. This one change would shock her more then all these other changes combined.

Its job done, The remaining miasma began to take on several solid forms before with a clatter, pieces of azure armor dropped to the floor.

The sound however, brought the Nightmare into the waking world. Stretching like a cat to readjust herself to a corporeal form, her eyes roamed the room, searching for something, before homing in on the scatted pieces of armor. With a smirk full of malice, she levitated the armor to her, before donning it and returning to her former glory.

However, the Nightmare still needed to sort through its newly acquired memories, which turned out to be quite informative, then again, when you have magic, you can usually imitate 70% of the stuff you see in video games in some form or another.

It was about this time that Celestia, Luna, and the Elements teleported in.

Luna was the first to speak up. "NIGHTMARE MOON, FOR YOUR CRIMES AGAINST EQUESTRIA, YOU ARE HEREBY SENTENCED TO DEATH!"

The Nightmare only chuckled at that. "Ponies... What is a pony, really, but a miserable little pile of friendship. But enough of that. HAVE AT YE!"

My mindscape.

I ducked another blast from that demonic pegacorn. (unises?)

"I WANT TO LIVE THANK YOU!"

"When I finnally kill you, I will have full control of my corporeal form, and then I shall plunge Equestria into eternal night!"

Like hell I'm letting you do that.

Reality.

"Do you really think you can stop me?" The Nightmare taunted.

Celestia unfortunately took the bait. "I KNOW I can beat you."

Smirking, the Nightmare only egged her on further. "Let us find out then, shall we?" and with that she charged Celestia, hoping to gore her on her horn. Celestia shot off a beam of magic, thinking she would stop to put up a shield, but instead, with a flap of her wings, The nightmare pushed herself out of the beams path, all while maintaining her charge towards Celestia. Upon reaching her, the Nightmare teleported just before impact, leaving a frantic Celestia searching for her.

Behind me? No. Can't come from below, so that only leaves... ABO-

*CRUNCH*

Several cries of "Celestia!" rang out.

The Nightmare had put her entire weight into a single stomp on Celestia's head, K.O.ing her instantly.

Luna, as well as the Bearers, were left slack jawed at the fact that the Nightmare had effortlessly taken out Celestia, and without taking a single hit.

The Nightmare turned towards the bearers, gathering massive amounts of energy into a roiling sphere of power at the tip of her horn, and then she spoke. "Thus the blood moon eclipses the sun, and darkness reigns again." Sensing that this would certainly kill the Bearers, Luna shot of a beam of magic hoping to distract the Nightmare, it worked, too well.

Still maintaining control of the orb of death, the Nightmare turned towards Luna with a snarl on her face. "You shouldn't have done that..." releasing control of the point farthest from her, the Nightmare fired a beam of super-condensed energy at Luna, the backlash tearing up the ground behind her.

Luna didn't even have to to realize just how powerful that beam was, before it plowed into her with the force of a meteor. Her screams, even use the Royal Canterlot Voice, were drowned out by the sheer energy buzzing in the air.

When the last of the ray of death had washed over Luna, what emerged left the Bearers in shock.

Her armor had been vaporized, with every part of her body facing the blast having the fur burned off. With a wheeze, the Princess of the Night toppled over, unconscious.

At this sight, Rainbow charged the Nightmare, snarling like a rabid animal...

Only for the Nightmare to duck under it, and using her wings, propelling herself upwards, while dealing a brutal uppercut to the cyan pegasus sending her flying into the ceiling, where the impact broke one of her wings, before she plummeted down and broke one of her legs.

suddenly, the Nightmare turned, and shot a weak beam of energy at Rarity, catching her completely off guard, before it knocked her into Applejack, stunning both of them.

Hearing the sound of magic charging up, the Nightmare spun, finding Twilight preparing some kind of directed blast spell, with enough energy that if left undirected, would level the entire castle. Much to Twilight's surprise, instead of a counter-spell, the Nightmare battered her aside with condensed pieces of telekinetic energy, before slamming her into a wall, dazed.

The Nightmare smirked, before going over the events in her head. "Now then now that that's out of the wa- Wait, wasn't there six of those annoying foals?" Upon opening her eyes again, she was met with what could only be described as twin orbs of hellfire, attached to a butter yellow pony's face, boring into her mind.

"I know your in their. You must fight it! Do not let her boss you around in your own mind, you're in control there!"

These words triggered something. As the Nightmare dropped to the floor, squirming in pain.

Mindscape

Ohcrapohcrapohcrap, I'm cornered! I don't want to diiiiieeee!

That demonic pegacorn closed in on me, with a grin that would make the Devil himself weep with joy at the misery to come.

"I know your in their. You must fight it! Do not let her boss you around in your own mind, you're in control there!"

Wait, that right, this is my mind! AND YOU CAN'T HAVE IT!

"Ohhhhh laaaadyyyy!"

Oh, she's in for it now...

After all, one does not simply suddenly understand the entirety of the internet at once.

Reality

"Arrrrrrrrrrrrrrg"

I woke up. Body feels weird but don't care must warn those, ponies, I guess, to stop me now, before that demonic thing takes control back. They were floating in the air, surrounded by pure energy, but they were hesitating.

"Whatever you're going to do, do it NOW, before she regains control!"

Suddenly, rainbows.