The Rainbow of Harmony wasn't enough to defeat Azazel, a being from another dimension. Twilight and her friends sacrificed their lives to give the seal the power it needed, but Twilight was left behind. Distraught by the turn of fate, she locked herself in her tower, searching for any possible means of bringing her friends back from the dead. Celestia and Luna went seeking answers as well, in the hope that it could help Twilight.
After three hundred years, Twilight has read nearly every book in the archives to find the answers. A strange theory about souls gives her a chance to bring back her friends, but the spell goes wrong, and she wakes up in another body: a human's body. Scattered across the land, the spell does bring her friends back, but they're also in unfamiliar forms.
Equestria isn't the country that she or her friends remember. After three hundred years without any monarchy, it's nearly unrecognisable, but it's still their home, and they need to defend it. For there are still threats to ponykind from outside, and Azazel is not without aid from inside...
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Liberties taken with canon: Equestria Girls never happened. Everything else up to Tirek is ancient history in-universe. I haven't seen Season 4, so any nods to that are (probably) coincidental.
If you click the 'source' button on the bottom right of the image, it'll bring you to the gallery that inspired this whole thing. However, I won't be using all of the ponies shown there, and I may change a few things or transform a few ponies that aren't in there.
In case anyone gets confused, here's all the copyright stuff:
Most of the characters belong to Hasbro, and these depictions belong (mainly) to Yatonokami. Cloud Skipper and Midnight Blossom (actually, most of the Royal Guards) belong to Equestria-Prevails. There may be other characters later who belong to other people, so I'm just going to say here that I own nothing except this story and maybe one or two OCs, such as Azazel.
Spoilers in the comments, just like everything else.
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Unfortunately, I've decided this story was basically just not going anywhere, so I cancelled it. I am still planning to do something with the concept once I'm done with LAT, though.