Edit: this is just a One off. Also Derpy's my current player character in a Modded run im doing of Fallout New Vegas currently.

Derpys past was a mystery to some. There were a few that thought she was a Ghoul from the prewar era. Others simply didnt want to cross her as she had been called a Spirit of Vengeance. She was a package delivery mare, but that didnt mean she didnt know how to handle herself when the time was right. She was the one mare that you never wanted to cross when she was determined.

You can just call her Courier Six.