K-7 is an agent with the British Secret Service.
Having as yet only very limited information about this series, namely two disjointed pages from one of the recorded graphic adventures, it is hard to say anything informative about this operative.
The time period for the missions that we know about is the early 1950s. The Cold War has only recently gotten started as the actions of Soviet Union contrasted greatly with that of the Allies working under the Marshall Plan. The latter sought to help the defeated countries regain a semblance of normalcy to avoid the same issues that World War I created by seeking to punish the losing countries. The former chose to grab control of as many countries as it could, putting its own chosen government leaders to expand the ideals of Soviet-style communism.
The British has the use of its stable of operatives working for its hush-hush Secret Service (MI6 or something else, it is hard to say). It eschewed using proper names for these covert warriors, either real or made-up, choosing instead to refer to them with codenames. The one that we are allowed to learn about is Agent K-7.
From the limited access we have to the missions, we can discern that K-7 is a very athletic (possibly) blond-haired operative usually seen adorned with a pencil-thin mustache. He is, as was the case for most men in that decade, commonly dressed in a dark suit and tie and an ever-present fedora.
K-7 is quick to take action, often with the use of his fists, K-7 is not the least bit adverse to show his earnestness by placing his fist forcefully up against the jaw of those who annoy him, especially if the offender has chosen to pull a pistol on him.
The agents from the communist countries of the Iron Curtain are K-7's primary opponents; K-7 will be called upon to travel throughout Europe to take on the enemies of the West.