Nathan McBride is a security consultant.
He and his partner, an older man named Harv who is McBride's closest friend, had served together for many years in the military, seconded to the CIA as snipers, long-range take-out specialists. They were considered about the best in the business and had achieved an impressive tally of victims before a mission to Nicaragua went terribly wrong and McBride was captured.
As the series begins, McBride and Harv have moved on from the horrendous consequences of that failed mission, a failure that left McBride in the clutches of a psychopathic interrogator who took enormous pleasure in disfiguring the 6'5" Marine. Several years of plastic surgury were not enough to remove the criss-crossing scars on his face and torso, evidence to all who looked at this once handsome man of the indescribable agony he had endured. He had survived and though the nightly dreams brought it routinely back and the face in the mirror never let him ignore it, McBride learned just how strong he could be.
Operating out of San Diego, the two men run a very successful security business in which they and the numerous trained operatives in their employ can find the holes in a business's protection and provide ways of sealing those up. Whether it is physical security or cyber, their company was the best to call to stay safe. With both men in their forties, though Harv is on the higher end, their futures are financially secure.
McBride's had been long before that, though he did not think of his heritage much except with a grimace. His family had been successful long before his birth and his father had parlayed that success to achieve another success in the U.S. Senate where he had served several terms and reached a position of considerable power, enough that it was more likely the powerful called him for favors. The relationship between the two men is strained at the series start but improves with time.