How about a AU Luna&Queen Chrysalis team up fic where:



1. They fight to againist a corrupted Celestia to save the land from Terror Nova, and after a few chapters they win, but need to figuer out what they will do next, and a 1,000 years later Sunset and Twilight become their students.



2. Chrysalis and Luna have met before (a one-night fling, Goddess-school buddies, a diplomatic meeting?) meet pre-wedding and Luna comes up with other ways to feed her subjects, and they worK together, with Cadence, to show Twilight the truth, and they try to find out why Celestia turned evil/crazy so they can save her!