Bewitched Amore and Nightmare moon. A poisonous duo, even more powerful than Celestia or Twilight, and Cadence and Luna. In some cases.
The world of Equestria is under threat of being transformed into a dark world, saturated into colour balances of blue, black and purple.
The Elements of harmony contained, and soothed into a world of darkness; Its holders' minds bound by evil.
"There can only be one princess of Equestria!" Luna had once said.
There is only one princess of Equestria now…and it's not Luna.