Paladin is an agent with American Intelligence.
That is just a wild guess. Since I have next to no information about him, guessing is the only option available.
We have only references to three adventures about this person, someone we assume to be male, that being the covers of the publications in which the recorded missions were presented. The first gives nothing in the way of information as it pertains to a different person. The second shows only a mention of the adventure's title. It is the third that provides anything approaching useful intelligence and that is thin at best.
In that third presentation, the image shown, going on the assumption that it pertains solely to that adventure, is of a car accident with the stylish roadster having hit a tree. The passenger door is ajar and a woman wearing what looks like a slip is on the pavement trying to rise after apparently crawling from the crashed vehicle. Nearby a satchel with several important looking documents fallen out is being pulled away by the arm of an otherwise unseen man. The only clue to his identity comes from the bottom of a braided uniform sleeve which gives the impression of being German.
The protagonist of these adventures is Paladin, Master Spy on Spies. The last part of that can tell us that the individual is in the counter-intelligence business, in other words a spy-hunter. It would be his job to ferret out those foreign agents trying to get intelligence on America or worse, perform acts of sabotage or terrorism on its shores.
But the name Paladin is intriguing. The historical usage is that of the twelve knights of Charlemagne and normally denotes a heroic champion or defender of a noble cause. So the question remains, is the term used here merely as his actual name or is it an indication of his calling? I have no idea.