Sherazad is an agent in British Intelligence.
Specifically, she works for the Bureau of Special Cases, or B.O.S.C., a very secret department that handles, as the name implies, the special cases which none of the other departments are equipped to tackle, or would want to. While some such bureaus in fiction have used legitimate companies as a cover for their activities, the B.O.S.C. goes for a much stranger way to hide their presence. They work under the cover of an actual religious organization known as the Order of the Brothers of Love and Succour.
This group of devoted friars has its headquarters near the Tower of London and the majority of brothers who live and work there are true believers but a handful are actual agents of B.O.S.C. who came into the organization to act as a publicity department. Many of the aging brethren were skeptical of the intrusion. This skepticism became jaw-dropping amazement when the leader of that new group, Brother Joshua, had the temerity to hire a "secretary" who was female.
That secretary seldom visited at the priory. She never did any secretarial work. She definitely was not a part of the religious group for though she made sure her attire when showing up was respectable, it did nothing to hide the fact that she was a woman of exceptional attributes.
As the three-book series starts, Sherazad has been an agent with the B.O.S.C. for just over three years and she had already accomplished enough that her fellow agents greatly trusted and respected her abilities. She is not afraid to tackle tough cases and to give her all but neither is she flighty or rash in her actions. She is fully aware of the fact that a wrong move can kill but inaction can often be just as fatal.
Sherazad is a woman, probably in her late 29s, of apparent independent means for she lives in considerable comfort in a Chelsea home and drives an expensive Jaguar sports car. Her clothing is always tailor-made and of the latest trends. With a stunning figure, a beautiful face, flawless creamy complexion, and shimmering red hair, Sherazad is a powerful force even before she starts to use her incredible brain and her not-to-be ignored fighting skills.
What her full name is and whether Sherazad is a first or last or even a real name is never discussed. What is shown over and over is that she loves her work, she loves the excitement, and she loves making a difference. And she always does so her unique way.