In a few words she is an Alicorn, she is an ex patriot from gods knew where

She was a black alicorn, forged on her home world as a beacon of light or something like that given the outfits she tends to wear all the things you really need to know about it is she is quite a nice person and well educated perhaps of high nobility either taking a break from her real life or exiled or some minor preconceived slight.

Word to the wise she does have a VERY elaborate cod piece and why yes it is filled with horsey goodness