Breed is a part-time agent with the CIA.
That is my way of saying that he gets roped into working with a full-time Agency operative named Anya Stein on more than one occasion. In my opinion, he does not go looking for her in the hopes she might have some near-suicidal assignment he might be able to make less death-sentence-ish; she is the one to seek him out. The first time is happenstance. After that, she has been shown just how good Breed can be in a fire-fight and when things go really pear-shaped so she will either give him a call for help or, if he is already in the middle of the trouble, hook up with him as there is safety in numbers.
Former Delta Force member having reached the rank of Chief Warrant Officer, Breed had joined the military several years before the Towers fell and had already gone through Army Ranger training to then be chosen for the highly elite Delta. As he watched the calamity on 9/11, he knew his world had changed forever. Breed would remain with that organization until five years before his first recorded adventure and our introduction to him.
If you noticed that I have not listed any first name for Breed, the reason being that as far as I can determine in the six adventures (so far) his given name is never mentioned. He is always addressed as Mr. Breed when formalities require or just Breed when friends and others address him. He apparently is happy with that as he never takes offense at it.
Breed hails from the Flathead Lake region of western Montana where his Green Beret father and his teacher mother were living when they brought him into this world and even after the dad died during the Vietnam War when Breed was just five, they remained there until her death years later. Since his enlistment, though, he did not have much reason to return until recently.
Breed is a trained counter-terrorist operative who chose, after a career with Delta fighting in Iraq and Afghanistan and other places not so officially mentioned, to give it up though his frequent nightmares tell him that the scars remain.