We've all seen stories where Nightmare Moon is used, once more, as the main villain, or a major villain. But what about the few where Nightmare turns out to be the hero?
The methods are irrelevant. Whether she's a co-ruler who's not liking the tyranical road her sister is taking, or was somehow turned from a monster into a good character, or just a tyrant herself who's working with the Mane 6 to take down a bigger threat, the common theme is that she's in the hero's post, if only temporarily.
Any and all people can post stories here, but please make sure that the post sticks to the idea.