Sombra's reign is at its peak, he has full control of the Crystal Empire and all ponies shudder at his name, he has all the power he could ever want. He thinks everything is complete until he meets one pony who does not fear him, perhaps she has the potential to be his greatest weapon. Only time will tell as he begins to teach her...

Note: This is basically me sharing some of the headcannon I have about the Crystal Empire and Sombra 1000 years ago. Hopefully it goes over well.