Carl Logan is an agent with the JIA.
The Joint Intelligence Agency is a highly covert organization funded by the U.S. and the U.K. It maintains a fair sized group of agents operating around the world, lead by a senior official with many years in the intelligence-gathering business and overseen by politicians from both countries. The agents were broken into six groups, each with its own leader, and Logan was one of the best in his group.
Was is the key word as at the time of the first recorded adventure, he had gone inactive nearly half a year and was only now being pulled back into service. The question on his superiors' minds was whether he was ready or too far gone. His immediate supervisor, named Mackie, is determined to get his man back on track but Logan does not make things easy for him. Logan is by no means the most respectful part of any team and after the year he has had, he cannot really say for certain if he wants back in.
Still, Logan is good at what he does and even with the bender he has been on and the rust that has surely started to set in, he is still one of the best there is in the field and he has to be to stay alive. Unless you consider the nightmare from what caused him to go on his bender. Or you throw in the shakes that he gets which he never experienced before his trauma. All this might sound like a man who is a loss or it could be a man who is learning what it is like to be a human again.
That would be a change for Logan - being human, that is. His childhood was, according to him, pretty horrific until he had grown big enough to not be a punching bag for his foster father. Then he began to run with a very unpleasant group as a teenager doing things no one would be proud of. At 17 he was selected by Mackie to be a part of the JIA and for the past 18 years he had been an agent who spent far more time thinking how to get the job done than thinking about what it was doing to him. Then came a messed up op against a sadist known as both an Islamic terrorist and a money-hungry capitalist and the things done to Logan when his cover was blown are the things nightmares are made of. The nightmares belong to Logan.
Logan's life will change quite a bit through the course of the series. Even his name will change as he decides at one point to break away from the only career he has ever known. One thing that will not change, however, is that people will get very nasty around him and he will have to get even nastier.