Author's Note:
This is entirely fan-made. I have no intentions of wanting to ruin the My Little Pony: Friendship is Magic series for anyone.
If you don't like it, you don't necessarily have to read it. No one is forcing you to. ;)
P.S. This first chapter is the prologue and is basically describing my O.C and her role if she were in any of the Equestria Girls movies.
The six Elements of Harmony were always used to defeat the evil forces of magic in Equestria. But it wasn't until Twilight Sparkle traveled to the alternate universe that she discovered there was actually a seventh Element of Harmony. It was so unnoticeable, but yet so valuable, that even the fact itself was pushed far back in Princess Celestia's mind that she had forgotten to tell her. Only once had Twilight ever seen the mere mention of it in one of her many books about the magic of Friendship. The symbol itself was dark blue and took the shape of an angel. This newfound element was known as "Melody". And Twilight knew there was only one mare who could have been a possible keeper of that element.
Her name was Heavenly Angel.
In her own universe, she had come across her multiple times, and the pegasus of pale white flank and soft light brown mane always greeted her each time with a heartwarming smile. Nothing more than a gentle "Hello" passed her lips. She coincidentally had the same cutie mark shape that the "Melody" Element of Harmony took form into, with the exception of two music notes floating outward from the main part of her cutie mark. But that wasn't quite enough evidence. But quite often Twilight Sparkle would pass by her house, which was a white boutique and castle-like structure similar to Rarity's, and hear her vocalizing merrily as she went about her business. It then at that point became more certain that she was the one.
The very first time she traveled to Canterlot High School, Twlight noticed that she was a very unique girl herself. Before she united the student body together, she observed that Heavenly Angel could sit at four separate lunch tables in the cafeteria of her choice. She was a bit of a fashionista(and quite beautiful) like Rarity, so she could sit with her and her friends, yet at the same time she was shy and quiet like Fluttershy. Therefore she could also sit with the other shy and quiet students. Heavenly Angel also had as much intelligence as Twilight Sparkle did, so she and her would potentially have been friends, given that they would approach each other the right way. From time to time, she also sat with members of the CHS choir considering the fact that she was a prodigious singer.
Heavenly Angel didn't play as much of a role the first time Twilight traveled to that alternate dimension. In fact, she was at first like any other student going to the school. But once the Sirens, or I should say the Dazzlings, came about, that's when both Twlight's hypothesis was confirmed and Heavenly Angel's true colors were revealed. Next to Sunset Shimmer, she was needed just as much to stop the Sirens from taking over the school and everything else after that. Melody was an extremely necessary element in vanquishing the forces of evil at that point, and it was certain they would need her in their next adventure yet to come.
Thus, the Mane Six then became the Mane Seven.