Keys is an agent for British Intelligence.
He is known to the rest of the Intelligence community only as the Queen's Investigator and the few who know him personally know only the single word he uses for his name. It is not even his real name but more of a title assigned to whoever holds his position. According to the first adventure, "the Q.I. is considered the hereditary head of the real Secret Service. His job is to protect the realm. The tools of his trade are money, sex and violence." Keys has his own seal, that of a White Unicorn, and messages with that sign on them are said to have priority over all others.
In the first adventure, Keys works mostly alone, using the services of manpower from the various agencies of the government. In the second book, having seen the extent of new dangers to the country, the Crown has allowed him to bring back the "Battlejacks", the term used to describe agents who answer to Keys alone. For many years after the first Keys went to work, he was in charge of a small group of agents called Cloaks (women) and Daggers (men). They were Keys to command but they were phased out over time until this Keys resurrects the department.
The current holder of the title of Keys is in his late 30's and has held the position for over a decade. During that time, he has saved the county on numerous occasions and earned the respect of most who know of his existance. The remaining few probably do respect him as well but their distaste for his methods, his manner, and his way of solving a problem has overridden their ability to admit it.
Keys is a very brusk man. He has little patience for elected officials and none whatsoever for the sychophants who accompany them to office. He deals with bureaucrats in a short and demanding manner and has no time to listen to their complaints. His personality is matched by the violence he is willing to perform in the completion of his missions. He is known to kill without hesitation or compunction if he feels the job requires it and would have a hard time understanding those who would fault his decision.
However, for all of his usual ill-tempered ways, Keys is a man devoted to his job. He knows he is often the last line of defense and he is also aware of the lineage that came before him. Failure is always a possibility, he knows, but he is determined that it will not be by him.