David Seven is an agent with Intrex.
According to a brief on that organization: "International Trade Experts is an organization formed by a group of wealthy philanthropists (anonymous) who make yearly grants to sustain their pet project. The purpose of the organization is simple; it copes with any problem or difficulty that may crop up in world affairs. All allied and disparate hazards of civilization can be dealt with by this body of extremely professional people who number scientists and skilled technicians among their colleagues. The unwritten motto of International Trade Experts is clearly stated in the credo: Men Must Live In Peace."
There are really two agents who deserve to be called The Man From Intrex. David Seven gets top billing but his colleague, friend, and often partner who can also wear that label is Miles Running Bear Farmer.
About Seven it is written that he is "deceptively lean, quiet-voiced and quiet-faced. The world knows him as one of the finest young legal minds available for outlandish fees".
For Farmer it has been stated that he is "that rarity among statistics: a full-blooded Cherokee Indian who went to college, graduated with honors and leaped to the forefront as an outstanding exponent of the new approach in his particular sphere of his field - public buildings, municipal centers, auditoriums".
So both agents are experts in their "official" line of work, both worthy of respect and admiration. In their unofficial capacities as agents of Intrex, they are unsung by the general public but highly regarded by the powers that control that organization. In their role as covert agents and often assassins, they answer to Samantha Follett, ostensibly the business manager of Intrex but really the spymaster who calls the shots and hands out the assignments. They refer to her as 'Sam' though never to her face.