(The epic cover art was drawn by Mutter Butter! Thanks to them!
https://www.fimfiction.net/user/297066/Mutter_Butter)

Eons ago, in the trades of Nekravol, the great Khan Maykr sold away large stocks of worlds and planets that were once under their jurisdiction to the Dark Lord of Hell. Amongst these worlds being the peaceful land of Equestria. The Dark Lord saw the powerful magic that inhabited this equine ruled land and decided that rather to invade immediately, it would be wiser to save it in an emergency where he was no longer in power.

Equestria, a land where almost nopony experiences grievances, pain or agony. Literal sunshine and rainbows. However with new revelations about this world, it's inhabitants may experience a drastic shift in their hopeful home.

Ever since a weird red substance was discovered by Applebloom, peculiar things have been occuring around Ponyville. Frightful creatures, odd diseases and strange events. All much more frequent than usual. Could this amount to something much more substantial for our equine friends?

(Supposed to happen between the end of Season 6 and the start of Season 7 and after the end of The Ancient Gods 2, the last DLC of DOOM Eternal. If you are here for the action, Cordial Affairs and all the Mission chapters might be what you are looking for.)