David Larkin and Samantha Colt are agents of an unnamed American Intelligence organization.
It falls under that umbrella unofficially because officially it does not exist. It is not even a government-sponsored department. It might get a good chunk of money under the table from many of the alphabet agencies, as well as other 'creative' means, but it is not truly answerable to anyone. Except the Judge.
"She was actually a retired federal district court judge and you might have even heard of her. She had spent her life in public service and was friends with many powerful people. She knew just about everyone who was anyone, and knew just about everything there was to know about most of them. She had made it her business throughout her career to know what was going on and who was doing it."
A couple things everyone who knew the Judge knew were that she was "unfailingly honest" and that she "devoted her entire professional life to making the world a better place". And being independently wealthy all her life meant she had to be beholden to anyone. It was many years before the adventures we can read about that she and several others over time came to the idea of forming "an independent entity, a shadow agency that would be tasked with performing certain operations that other organizations, for one reason or another, could not or would not do". "The Judge, of course, informed the group that such an organization would be completely illegal and contrary to the principles of the U.S. Constitution. She also said that it was necessary, and she agreed to help create it. That was how she became the chief executive of a company that officially at least, did not exist and never had."
That is the group that Larkin and Cold belong to. Well, belonged is more accurate.
When we first meet Larkin, and shortly after, Colt, they had some time before ended their connection to the group. Some things had gone wrong through no fault of theirs or the Judge but which made them both feel they had done enough and that moving on was in order. Both picked up extra money here and there doing odd jobs suited to their specialties now, largely out of a need to do something, but they had moved on. So, of course, life will bring them back on occasion to working with the Judge.
Larkin is likely in his very early 40's. He was recruited by the group out of U.S. Navy boot camp because of his exceptional skill-set shown during training and for the next sixteen years he worked for the Judge. The first three years was spent in intensive training learning an impressive range of skills, some of them quite illegal to use, before being put into the field for the next 13 years. He describes himself as "average height, average build with pale blue eyes and coarse light hair. I don't look particularly strong or quick or even smart. I am not memorable, which in my line of work has often worked to my advantage. It also doesn't hurt that some people tend to underestimate me".
Colt is - unique. She is "lean and fit and muscular, with short black hair and smooth, tan skin". She is a bit more than ten years younger than Larkin but neither really knows because no one, not even she, knows for sure how old she is. Her back story is so interesting that the fourth adventure available to us is devoted to how she came to be the young, fascinating woman she is. In a nutshell which does not do her justice, she was part of the foster systems since she was little and to avoid a very bad situation she fled into "the streets in Baltimore, fending for herself, living in abandoned buildings and cardboard boxes, stealing whatever food she could find and anything else she needed. Since she was just a kid, she was a target for predators, so she had to learn quickly how to defend herself and others learned to pretty much leave her alone. She also had to learn to stay out of sight, not only to avoid people who might bother her but also the police". Eventually, as a teenager, her luck ran out and she was caught shoplifting and the police came and she fought back and that is how she came to the attention of the Judge.
For the past several years, Larkin and Colt have been partners, two people who have no one else except each other and who have found they really do not need anyone else.
One interesting note as to how both Larkin and Colt are able now to pick and choose what they do. Larkin tells us how his mentor in the group told him early on that "we have no budget. With a budget comes accountability, and with accountability comes oversight. We have neither. We finance our own operations. In this line of work you'll often come across stacks of cash - a drug dealer who's just made a sale or is about to make a buy; some tin-pot dictator who keeps an emergency fund in his mattress. When you see it, take it. Get deposit boxes in a few banks. Open a few offshore accounts. Stash the cash. You never know when you might need it."