After being reformed, he needed a place to let out all his chaotic desires, so he made an Abridged Series. That's why his UFP counter part, seems just like Discord if he spent literately all his time being a Jerkass troll: That's the point.
He may even get jealous of said sibling when Twilight uses her instead of him, later in the episode.
Luna will beat the ever living crap out of Celestia, before taking the thrown and earning everyone's respect, Twilight will finally be rewarded for all the times she's saved the world and Luna will make her, her second in command, Rarity and Sweetie Belle will bond as sisters, Rainbow Dash will finale be accepted by the town upon getting past her Jerkass behavior, Fluttershy will learn to assert herself healthily and demand the respect of everyone, Pinkie Pie 2 will just forget about her plans for The End of the World as We Know It and begin a happy life in Ponyville, Applejack will be sent to prison, but with the support of her friends will successfully reform, Spike will stand up to Twilight and force her into letting him be free for the first time in his life, the CMC will earn their Cutie Marks, Applebloom will stand up to Granny Smith and they will all realize they are True Companions and will live happily ever after.