Chuck Brandt is a freelance agent.
That right there is a major disservice to the man and largely inaccurate but what he is gets rather complicated so it is likely the best description for now.
For over a decade, Brandt was one of the very best assassins the CIA had. He was known as the Ghost for the way he could come and go almost unseen, leaving his target dead in his wake. He had a conscience and his own set of rules but if you were in his sights and you fit within his guidelines, you were dead.
Outside of work, though, he had a life. He was quite happily married and enjoyed outdoor activities with her that more than made up for the tension and danger he faced on each mission. His wife understandably bemoaned his long absences but stayed with him and enjoyed the time they had together.
When she died in a climbing accident, he fell as figuratively as she did literally. His work had no meaning. His life was just as empty. He needed a change. Which is why when he finally pulled himself from his grief, he looked elsewhere for work.
The first company to hire him was a private intelligence organization called RUMAN (meaning unknown). It hired him as a recruiter, working among the refugees to America to find those who might be useful in serving their new home as spies or informants. That relationship would take a major downturn, as depicted in the first adventure.
The second company to take him on was another private intel firm, EREBUS (again unknown). That relationship worked for but a short time before it took got on the wrong side of Brandt and paid for it in the second adventure.
After that, Brandt was pretty much on his own.