Meet Cross-Hit.  
Bat pony that is an MMA/Cage Fighter.
 
Lived in a rough area, raised on the streets. Has a history of violence and criminal activity (nothing as extreme as murder, arrested for crimes such as theft, assault, vandalism and disturbing the peace).
 
Was considered weak for most of her life, being a prime target for thugs. Learned to defend herself and beat up everyone that used to make fun of her or bully her.
 
Makes a living by competing in underground/illegal street fights and fight clubs. Using them as a way to vent off her anger, which normally results in her pummelling her opponent even after they have already lost. This behaviour both makes others fear her, and has resulted in her getting into trouble and kicked out from certain joints because of how violent she can be.
 
Self-taught martial artist. Too poor to get lessons from a Dojo or club, instead learning most of her techniques from watching self-defence videos and books/guides. Fighting style mainly consists of her combining hard and fast hitting strikes and kicks, mixed in with several dirty/illegal moves (Biting, hitting the genitals, eye pokes/scratches, hitting the throat ect).
 
Doesn’t have much friends, and is a loner. Secretly hates her life and wishes that she could just restart her whole life so she wouldn’t end up like this.