What if Twilight had to replace Stygian in the Pony of Shadows? For a while, they'd just have to move on with their lives until The Pony Of Twilights, formally The Pony of Shadows could be seen again and the Mane 5, even some with relationships, have to fight to get their friend back. But can they?
(( image for cover if links being stupid https://www.deviantart.com/dragonfoxgirl/art/Corrupted-Commission-709102415 ))
Note: Spike in my AU will have also come to Ponyville due to the Rainboom and will be the same age as everypony, around 24.