Sophia is the daughter of an English noble. She is cultured and highy educated. While gowing up, she escaped the stuffy drawing rooms of London to run wild through the back streets whenever possible. She spent many an hour watching the mechanics in the shipyards and airyards at their work until they finally let her apprentice.
The Boss picked Sophia up for side jobs based on her invaluable skills and flexible ethics as well as her skill at slipping in and out of various personas. Sophia was never one to worry about getting her hands dirty as evidenced by her willingness (for a price) to aid the Butcher's escape from a prison hulk on the Thames and transport them via stolen airship out of England to the States. As business has remained lucrative on this side of "the Pond", Sophia has remained in the area working in league with the Butchers as the mood strikes her and as the financial need arises.
Along with Auntie Social (aka Singleton), Sophia often serves as the "Research and Development" arm of the Butchers. She is a superb weaponsmith and an excellent markswoman. She favors a long range rifle to all other armaments.
May the Almighty have mercy upon your immortal soul if you're every unlucky enogh to earn her "special" attention.