I'm looking for a story featuring Discord. I don't know the exact name, but I do remember that it was on fanfiction.net, and not fimfiction.net. (I think) The cover art was this: I distinctly remember it being on Equestria Daily. It was definitely one of the darker My Little Pony stories out there. I also remember that Nightmare Moon appeared in it and it broke off from canon shortly after that.