"She is our Shield, the benevolent protector of all ponykind.  This was not always so.  She was once a ghost, unfortunate enough to be forged anew in the fires of fate, and cursed to bear a sharpened edge that our foes would do well beware."

Reader - https://www.youtube.com/channel/UCpV5X_81Fi_SslSjE4t_eWg

Story - http://www.fimfiction.net/story/159306/sweet-celestia