Hey guys this is my origional OC DO NOT STEAL
Her name is Queen Rainbow Gems and she rules over all of Equestria but she lets Celestia go around and do all her queenly duties, since she's actually Celestia's great-grand-daughter so she feels obligated to let her Nana Tia run Equestria for her.
She's really good at magic, since her dad was a half-zebra half-dragon, and her mom was half changeling and half alicorn so Rainbow Gems is too. Since she has so much magical blood even complicated spells are really easy for her, and she can time-travel easily. She actually went back in time to help Celesia seal Nightmare Moon and while she was there she had an affair with Star-Swirl the Bearded who was secretly an Alicorn too and gave birth to Twilight's great-great-grandfather which is why Twilight is so good at magic too.
While she was back in time she found out that Celestia is actually half Changeling and uses a lot of her magic to appear like a normal alicorn and feeds off the love of her subjects, but she's still a good ruler. She kept this secret for her nana because she loves her but then when Chrysalis attacked Shining Armor and Cadance she fought her and Chrysalis revealed that she was actually cloned from Celesta's Changeling DNA. She helped Cadance and Shining Armor break the spell Chrysalis had on everypony becuase she's part changeling too and changeling magic is stronger than alicorn magic. She also went to the Crystal Empire with the mane six and Shining and Cadance and turned King Sombra into a god guy and married him so now they rule over the Empire together. She had to move away from Canterlot and Ponyville anyway because the mane six and Derpy are madly in love with her and kept stalking her.
Since she's so good at time spells Dr. Whooves comes to her a lot to help him save the world and she made him a Tardis since he's such a good freind of hers and she can make anything because she's that powerful. A lot of ponies are afraid of her because she's so powerful, and though a lot of them hate her because she's beautiful they're too scared to fight her in real life. Since she's part dragon she can eat gemstones and prefers them to any kind of food, except maybe love.
Oh and I didn't make her cutiemark I found it on 4chan