Description:To Serve In Hell (Update Part 7!)
Starlight Glimmer's attempts to stop the Rainboom pulled Twilight Sparkle into many possible timestreams. In one of them, Rarity not only survived Nightmare Moon's victory over the forces of light; she even managed to work her way into a position of relative prominence and comfort in Nightmare Moon's service.
But Rarity's generous heart has grown sick from what she has done and seen to secure that position, and she may yet find the courage to rise up against the wicked mistress of the night...
Additional Tags: What does "good" mean in a shattered world?