Sequel: Left Behind: Sunny Disposition
Apparently it was scouted and is on EqD too

Nightmare Moon was meant to be released after a thousand years. A momentous occasion for her but terrifying for all the ponies on her day of freedom. She would get revenge on her sister and cover the world in darkness and shape everything to fit it.

That was the plan, at least. Instead, something went awry with the spell and she wasn't released when she was supposed to be. The mare-in-the-moon is brought into a world with stagnated technology, giant cities, and no sign of her sister or any of the other immortals. In fact, ponies don't seem terrified of her at all, and the stay within the core of her powers infused and changed the alicorn's body drastically.

The alicorn had no obstacles left! But...she was also a relic of the past. A past everyone seemed to have forgotten. A past she could no longer look upon.

Artwork by ElkaArt. Link in source.
Big thanks to Kryostase for helping spot errors I've missed.

A group of pony radicals try to summon a demon to overthrow the princesses. Instead they got a human. They don't know what a human is.

((Pre Princess Twilight))

((Edit: Featured 5/11/2020. Didn't expect this to go over so well!))
((Edit2: Ch.8 featured 10/1/2020))
((Edit3: Featured 10/22/2020))
((Final Edit: Featured 3/25/2021))

His evil was legend. He was an entity of incalculable power and unparalled malice - his icy soul utterly consumed by his plans to destroy all of life, until he was stopped and defeated. But what if that wasn't the end? What if he was given a second chance, in another world? For he was not always like this. Nobody is born evil. But anyone can turn evil. Will he become a hero? Or is he doomed to repeat his mistakes and walk the same path as before, the Path of the Damned?

Edited by Zaleros, TimePrincess
Proof-read by: Bazing, Sage Probo, guardianxela
Former edit: Lazygamer313
Former last check-up (starting from chapter 139): Dubz
Chapters 132-133 proofread: Sixkiller5, DarkZonker, SmurfOnSteroids, Bast, Shadowfire, Wraithguard, Bazing, Sage Probo, guardianxela
Former proof-readers: Vrilix, Defias, Merchent343, TexPony
Fan Fiction Read on youtube by lunarassassin

Epub with styles (italics, bold): http://www.mediafire.com/file/l7flswrrl68do0y/rebirth-of-the-damned.epub, created by Halusm

AUTHOR'S NOTES:
1. This is my first fanfiction, so honest criticism is appreciated.
2. This is a crossover with Warcraft universe.
3. English is my second language, so you will have to forgive me for possible grammar mistakes.
4. Hope you like it.
5. There is a prequel called: Project Eclipse.

To escape from Tartarus is nearly impossible, even for one of great magical power. When you've lost your powers and are little more than a withered old centaur, it's even harder. But Tirek has a plan, one that will draw in a creature from a world where life is cheap, hats are plentiful, and gravel is king. Will the Spy take the opportunity to enjoy a well-earned vacation in this new world, or will he see the population of friendly, innocent ponies as just a fresh selection of backs to stab? It could be both!

(Takes place before the beginning of Season 9.)

Our protaganist's life (mine) turns from dramatic to tragic in a single moment...but then an out-of-left-field event happens, and I find myself in an alternate universe version of My Little Pony: Friendship is Magic where the only difference seems to be Queen Chrysalis hatches a new queen years before the 1,000th Summer Sun Celebration...and I'm that new queen.

Jumping in on this particular bandwagon. Tagged "Gore" for the opening chapter (and possibly later chapters) and "Sex" because you can't mention any part of the reproductive process without the sex tag on this site.

An homage to stories like The Substitute Demon, ALL GLORY TO THE OVERGOAT!!!, and 1000 Virgin Mares, 1 Frickin' Badass Dark Overdude, Infinite Facehoofing

One thousand years ago, the Princesses Celestia and Luna were blindsided by the return of the Masters of Equus. The cult of power-mad alicorns, thought to have been banished from Equestria forever, appeared in the middle of the Princesses' battle for supremacy, and caged them away. The rest of Equestria quickly fell to their might. Even the fearsome Discord was forced to his knees before them. All of Equestria was enslaved, and an era of misery began.

Now, one thousand years later, a lone unicorn mare has learned of a creature that might be able to overthrow the Masters. A creature immune to magic, overwhelming in size and strength, sealed away for centuries uncounted. A creature of ultimate evil: the Smooze.

Unfortunately for Starlight Glimmer, in trying to ensure the creature's obedience, she modified the summoning ritual a bit too far.

Because of her meddling, the soul of a recently-deceased human is pulled from Limbo, and given life, but not exactly a body. Now he has to help her save the world, or face obliteration.

Not much of a choice, is it?

Inspired by Pen Mightier and Bucking Nonsense, the legends who – to my knowledge – popularized the "human in villain's body becomes Equestria's savior" genre. May your inkwells never run dry.

For the longest time, Twilight Sparkle had problems with dating. Although she was the Princess of Friendship, the stallions she had attempted to progress beyond friendship with always seemed to shy away, sometimes at a rapid gallop. Well, this time she has the problem solved. If she can't find a stallion who will be romantic with her, she is going to make a stallion who wants to be romantic with her.

What could possibly go wrong?

Editors: Tek, Starlight_Glimmer, Mitch H, FTL
Picture Credit MoonlightFan on Deviant Art (Little Tigress on FimFiction)
Now on Equestria Daily

Isaac Archer used to be human. Used to, being the key word. After encountering a strange flower, Isaac finds himself reborn as the newest member of the royal family, an alicorn prince by the name of Dusk Star. With an OCD mother, and a too cool for school dad, Dusk finds himself having a rather interesting second life.

This story is a sequel to Freeport Venture: Blood and Iron

War rages throughout Equestria. The return of the Crystal Empire has seen years of strife and millions dead as Princess Celestia’s forces strain against Sombra's seemingly endless hordes.

However, the entry of Freeport’s forces turn the tide in Equestria’s favor. Archon Sunset Shimmer and her army smash into the fray, breaking the long, brutal siege of Manehattan and shifting the balance in Equestria’s favor. With Sombra's army falling back to his home territories, there's finally reason to hope again.

If only they knew something far, far worse than Sombra loomed on the horizon.