Raker is an agent for the Company (probably the CIA).
At least he was a member of the agency for several years when his status was voluntarily changed after the death of his brother in Vietnam. Angered that rich kids belittled the sacrifice the sibling had made, he agreed to go 'off the record' to be able to do work that the Company was not legally allowed doing. He would be expendable and, more importantly, deniable.
After that, he took cases the agency needed done surreptitiously on a contract basis. Though several of the missions have, according to Raker, required killing, he was adamant that he was not an assassin. His body count might indicate otherwise.
Being a contract agent, Raker, no first name ever given, charged a considerable amount for each assignment, making him have a tidy nest egg put aside. Since he was very good at his job, he was called upon often because he got the job done and there were always a lot of jobs that the Company wanted done but did not want to admit to.
Interestingly for someone who was so well regarded and so frequently used, the Company, to keep him in line and ready for the next job, never paid him for his work until that next job came up.
Raker works alone, usually. He prefers it and most people prefer to not associate with him. He is highly opinionated and his opinions tend to offend and anger people. He has no patience for anyone and enjoys telling people that. At times his jobs do require the assistance of others and for those occasions he has several people he routinely uses. They know and understand Raker and get along with him but it is not certain if they actually like him or if he cares about them at all.
Raker is a loner and it is probably best for the rest of the world that he stays that way.