I don't really know how this goes, but I'm going to try my best to come up with a good introduction, so bear with me.
I'm a gamer, an artist, and I have had a childhood that wasn't very pretty, so when I started watching My Little Pony, I decided "Why don't I make my own OC?" So I did. My OC is an alicorn, and she is very special, or as she sees it, strange. The place she comes from is not on the map whatsoever, but she remembers the name of it. The place she comes from is King's Island, or as some people called it then, "The Isle of the Great Alicorns" which everypony knew the "Great Alicorns" as Celestia's parents. Starshine never knew who her parents were, all she knew is the people who raised her found her as a filly, all alone under a bit of rubbish. The two ponies that raised her would always tell her she would become a princess like the filly Celestia who raised the sun. But she never found anything special or princess like about her, no matter how hard she tried. She would always go to school and get picked on, and the only ponies that made friends with her would always have little to no loyalty. She did not find her cutie mark all through school, and people teased her even more for being an alicorn with no cutie mark. She tried keeping in her feelings for a long time, and at last, on September 7th a terrible nightmare rose out from her latching on to her back, chewing off her half of her horn and tearing off most of her wings. The next day at school, people simply avoided her, for they did not want to look upon the terrible pain she was in. They pittied the pony, but their jealousy of her being an alicorn kept them from showing her any more kindness than they always had. The next several nights, the nightmare would come out and wear on her wings and horn, as if it wanted to make sure they would not grow back, nor heal. Starshine felt that the demon wore on her spirits, as well as her body, causing her to live in misery for most of her childhood. At last, like a rainbow in a rock farm, a pegasus pony by the name of Twine had befriended her one day. She spent a lot of her time trying her best to keep Starshine happy. She would bring her to her house, she would tell jokes and stories, and the night she realised that special pegasus pony wasn't going to leave like the others, a pure white pony sparked from her horn and defeated the demon, bringing both of them back captive inside her. Her horn and wings however, were still destroyed, preventing her from flying or using magic. Now she was simply an earth pony that was once an alicorn, with still no cutie mark on her flank. She knew that this would almost certainly draw attention to her, and this was the last thing she wanted. She felt fed up with this place, and she wanted to go somewhere, anywhere where she would be shown at least enough respect not to be picked on everyday. Troubled, she asked Twine of a place she could run away to, where people were kind to each other. Twine told her it was unwise to run away from home, but decided to suggest a place anyways. Ponyville, the land the filly Celestia lived in, was west from King's Island, and was a place of order and peace. She told her that the only trouble that happened was rare, but the place was very very far away.from home, and would take a long time to get there, plus she would have to sail across ocean along the way. Starshine thanked her, stayed one last night, and bid farewell to her dear friend the next day. She traveled across the small land with all of her possesions, plus some non-perishable food to eat along the way, and snuck on to a ship to Manehattan, sailing across the ocean for many days and nights, until coming to her destination at last. Manehattan was a place of very judgemental people, and she had to keep her luggage constantly on her back to prevent any unwanted questions about her alicorn race, or her blank flank. She continued to travel, and met a pony who seemed to be in a similar state than she was, even though she wasn't an alicorn, she had no cutie mark, and she seemed very depressed. She asked her what her trouble was, and she said she was being picked on because of her flank, even though she was an adult pony. She showed her that she had no cutie mark either, and told her about her intentions of moving to Ponyville. After staying a couple nights, she came up to her earth pony friend, stomping her hoof and insisting she move to Ponyville with her. The pony frowned, and refused. She couldn't leave Manehattan, for she wouldn't know where else she would find a job, plus moving to Ponyville would take a long time. Starshine stomped both her hooves this time, and said she wasn't ever going to get her cutie mark trying to fit in and living in a place that would just encourage her in doing that. This convinced the purple pony, and they both took a train to Ponyville. When they arrived at Ponyville, they were both, naturally greeted by Pinkie Pie, which threw a New Pony party for them, and at last, her friend had overcome her depression and found what she was meant to do. Her cutie mark flashed upon her flank, and Starshine smiled, wondering to herself when she would get her cutie mark, and what it would be...
More to come! Special thanks to Stormy Night, one of the special ponies that made themselves known in my OC's life. This backstory is rather general, and it doesn't pay much attention to specific details, but to be honest here, Starshine's backstory is mostly based on my backstory in real life.
Edit: Ok, Celestia lives in Canterlot *Smacks forehead* Also, Stormy was from Filly delphia, not Manehattan. Sorry about that.