Regina is a freelance agent.
In the Intelligence community, Regina (no other name given) is codenamed the Blue Queen. According to the series, the Blue Queen is a chess piece, an extra queen that is placed on the board and can then be used by either player.
Regina is called the Blue Queen because of her freelance status, an agent working for whichever western power can meet her bill as well as interest her in the assignment. The rumors about her refer to activities during the Trujillo assassination, the Suez Canal closing, and even a run-in with Khrushchev in his Cuban activities.
Her background information is sparse - mainly that she is an American citizen hailing from the mid-west. She apparently wants the secrecy and the mystery to stay that way.
Her cover for her travels around the world is that of a famous lounge singer, one who is immensely popular both for her voice and for her voluptuous figure. Wherever she goes, her reputation for great singing and great measurements have preceded her. This appeal works greatly to benefit her real job as dictators and crime bosses and other nefarious creatures are guaranteed to lustfully invite her into their homes, never expecting someone as desirable could also be so dangerous.
Two popular female action characters already in print at the time Regina came onto the scene were Modesty Blaise and Honey West. Both of these dynamite ladies had a handsome virile male assistant who is always horny but who would never think of making a pass at the boss. Not one to be left out of the fun, Regina has Randy Kidd, her piano player as well as her producer. He is also her able sidekick in her true business as the most notorious freelance agent operating in the business today. He also is always ready to lay down in the line of duty, ever able to prove his first name is both a noun and an adjective.