Your name is Trixie Lulamoon, or as you've taken to calling yourself The Great and Powerful Trixie, live your life as a roadside traveling magician for hire who performs shows from the comfort of your caravan.
This is what you've been reduced to. Performing pansy tricks to mere ponies who couldn't even start to comprehend the magical possibilities you had in you.
It's true that you faced off against Celestia's own protégé, one unicorn known as Twilight Sparkle. And you lost.
You have always hidden a grudge against her that is fueled with each cycle of the sun and moon passing. You became dead set to extract your revenge.
And now, the time has come. Your route as a magician-for-hire brings you back into Ponyville. Now it's time for you to face off against Twilight again, and reclaim what you lost that day.