John Pond is an agent with an unnamed intelligence agency.
The amount of information we do not have about this individual is, well, impressive, since he does work in a clandestine organization, especially one that is said to be ultra-secret. In fact, we know next to nothing about him and likely never will since the tales we have of his activities were penned a half-century ago.
The smattering of adventure recounts we have of Pond are all accurately classified as vignettes by the source I have on them. My online dictionary defines that noun as meaning "a brief evocative description, account, or episode" which exactly covers the handful of stories quite nicely. They are brief to the point of being almost non-existent, each being comprised of less than two full pages and able to be read in a matter of minutes. Obviously, it is not likely we would gleam any real intelligence in such a short period of time.
We know these few facts.
He is likely in his late twenties or early thirties, told to us by the fact that those whose problems have brought them into contact with Pond seem to instantly trust he will be able to handle them; a younger man would be far less like to carry such gravitas and an older man would not likely be out in the field.
He is extremely confident in himself because when he is faced with challenges, he accepts them without hesitation.
He works on his own schedule. When pressed for immediate results, he does not argue or excuse; he just sagely advises his 'clients' to trust him. He does not let them down.