Crime, is something that is present no matter where you look. Sure there are places that seem free of its influence, but scratch below the surface and you'll see signs of crime and corruption.
Even a seemingly peaceful land such as Equestria has its secrets. For unknown to many, the world of crime has quite the influence.
Applejack is aware of this fact, but when Granny Smith reveals how it ties into the deaths of Applejack's parents, Applejack is furious.
Before long however, she decides that there's only one thing to do. Teach the world of crime a lesson. And she intends to do so using their greatest weapon, fear.
And so, Equestria's greatest, and most mysterious defender is born.