Scott Pearce is a former agent with MI6.
Back in the day he was exceptional at his work, enough so that even now when he is talked about, the word 'legend' might easily be mentioned and it would have nothing to do with a false identity. Back when he did what he was asked to do for Queen and Country, he was very, very good at it. Which makes it all the more confusing for those talking about him to rationalize the fact that Pearce had been let go, to put it nicely, or shoved out, if a bit more honest.
When we catch up with him in the first recorded adventure, he is living 'off-the-grid' on an island off the Thai coast wanting to investigate the operations of a smuggling gang in the region. He will get interrupted in that pursuit with a different matter but he will return to it as soon as he could because Pearce is a very stubborn man unwilling to let something that annoyed or angered him 'just go'. working on his own as he is, he knows his job is considerably harder than it had been when he had an organization backing him but nowadays "Pearce didn't need to have faith in anyone but himself" so being solo was what he wanted.
Being alone was something that Pearce was used to. He had been abandoned by both parents when he was quite young and had "drifted from one foster home to another" getting into trouble on a regular basis. Then as he was about to turn a life of juvenile delinquency into adult crime and probable hard time, he was "rescued" by a headmaster of a tough Welsh school and almost thrown in the Army. There he showed potential and was offered a chance at the elite SAS. He'd served with a specialist unit, the Increment, which "provided operation support to MI6", hence his association with that organization.
Playing a major part is the activities of Pearce is Leila Nahum, a "digital security expert", an attractive woman with black wavy shoulder-length hair; her face having "Mediterranean coloring, her Greek nose, dark eyebrows and wide, opal eyes". Her looks are marred with "scarring around her neck and the flat section of her cheek where the bone had once been broken". Add to that the fact that she needed a sturdy walking stick to move on her feet or needed the use of a chair to get around, it is plain to see that whatever Nahum had been involved with before we meet her, she has paid a price for it (we are given graphic details about it but it is better you read them yourself).
Pearce and Nahum had met while both worked for the Firm and they had hit it off right away partially because "neither of them fitted the common media portrayal of spies" as both "were rough and rugged and had been through fire and pain to escape misery, dragging themselves up from nothing, creating such lives as they had through sheer invention and willpower. They recognized in each other the inner strength such journeys required and that mutual respect was the first step towards what had become a friendship."
Together they, and another veteran field agent by the name of Kyle Wollerton look into things that matter to them and because they are as good as they are, they tend to resolve situations in their favor.