Alexandria Kingston is an agent with the CIA.
As the blurb I read for the first recorded adventure indicates, "Like a viper, she strikes when you least expect it. She's the deadliest operative the CIA has ever known. Alexandria Kingston is The Griffin." That is her codename with the Agency and it must have been used a lot because while her actual identity is unknown to all but a handful of people, the Griffin in known, feared, and hated by a lot of bad people in the world showing that Kingston has definitely gotten around.
She was born Mandy Hall, daughter in an extremely disfunctional family. When she was five years old, she and her ailing twin brother, Andy, had been left alone for days in their tiny trailer home with little food. As her brother's illness got worse, the tiny girl went out into the night to seek help and was found by a woman driving by. When the two returned to the trailer, they discovered that the boy had succombed to the sickness, her mother had returned with her drunk boyfriend and had a fight, and the boyfriend shot the mother and then himself. Like I said, disfunctional.
The woman who had found her was Maggie, wife to Daniel Murphy, head of one of the Irish mob families in Boston and mother to several growing boys. Little Mandy was taken in by the Murphy family and raised as their own though officially she was just a friend of the family.
After Kingston graduated, she wanted to join the military to serve her country but the Murphy's convinced her she should instead try for one of the alphabet agencies. She chose the CIA and for the past almost decade she had become one of that organization's fiercest assassins.
"When she'd started at the CIA, it had been suggested she use a disguise and an assumed name at all times except at HQ or with her loved ones. The explanation her case officer gave was that her looks [she was quite breathtaking] were too unique for anyone not to remember. It was best to be able to blend in with a crowd, not to stand out in one."
Now situations back in Boston have brought her back home where a lot of people are about to learn just how deadly the Griffin can be.