But it did! A different kind of spark. I felt it the very moment I realized how happy I was to hear you, to see you, how much I cared about you. The spark ignited inside me when I realized that you all are my friends. You see, Nightmare Moon, when those Elements are ignited by the... the spark, that resides in the heart of us all, it creates the sixth element: the element of... magic.
Those were the words spoken by Twilight Sparkle, the Element of Magic, protégée of Celestia, savior of Equestria, as she ignited the Elements of Harmony and once and for all defeated Nightmare Moon. Or so they all thought. Darkness that has been growing for more than a millennium can not simply be banished by six young mares, wielders of the Elements or no.
Celestia knew this, but when you have reigned supreme for countless years, you grow careless. You start to believe that since time can not end you, nothing can. That's why when Nightmare Moon returned, Celestia simply sent the new manifestations of the Elements of Harmony to deal with the threat, rather then doing it herself.
Young and inexperienced, the Elements played Nightmare Moon right in her hooves. They transformed her exterior back to how she looked a thousand years ago, but they did nothing to change her on the inside.
Luna still remembered. She remembered the uprising, the failed rebellion and the fight with Celestia. A fight Luna should have won. For while her frame is smaller than her sister's, her magical powers are far superior. Celestia was never magically gifted, she could never do things Luna did. She couldn't even match her top students. However, Celestia had the Elements of Harmony, and not even Luna could match their power. So instead of remembering her sweet victory, Luna remembered the blinding flash and intense pain of her banishment; she remembered the millennium spent alone on the moon. She remembered everything, and now the time for revenge was here.
And so, given back her old looks and asked to once again rule Equestria with her sister, Luna set her plan for revenge into motion. The basics of the plan that had been formed during a thousand years alone on the moon were simple enough; kill the Tyrant that has ruled for far too long and take her throne. The details on the other hoof, had to be worked over a little. The world had changed quite a lot in the past millennium.
It took Luna a little more than two years to revise and finalize her plan and once again prepare Hoofington. The city had once served as her center of rebellion all those years ago, and it was just as easy to turn it over now as it had been the last time.
Now, two months after the wedding of Captain Shining Armor and Princess Mi Amore Cadenza, the only remaining obstacle was the very weapon that felled her all those years ago, the Elements of Harmony. Unfortunately for Celestia, the latest manifestations of the Elements would only be a minor obstacle. This time, Celestia would be the one to learn what it was like to have the Elements turned against her.