Brian Webb is an agent with White Dove.
Was and is again would be more accurate. We learn very early on that Webb had been an operative working for the mysterious man that he knew only as Uncle Mark. Mark was not really his uncle; it was unknown if he was anyone's uncle. That is just what everyone called him.
Webb had met Mark "just after he had gotten his second degree in Cambridge. He was invited for a job interview. He entered the offices with one name and exited few months later with a different one. He had become Brian Webb". Webb had worked for Uncle Mark for several years until six years before we meet him. At that time his connection ended (how and why is a bit vague to me) and he changed his name and moved to Amsterdam "leaving behind everything he was and trying to start a new life".
That new life would involve moving to America, changing his name to Kevin Butcher, and becoming a professor. And trying to forget the other life in the hope that it would forget him. It didn't.
Prior to his life as Butcher and even prior to his life as Webb, the man we know as Webb had an interesting though lonely life. "He was alone since the age of six. Boarding schools and Orphanages were his world. A child that nobody wanted to adopt. A child who was considered a monster because of his intelligence. A child who scared all the couples looking for a baby to adopt. He had learnt very early in his life that he could count only on himself. He had learnt early in his life that deception was everything."
This nomadic life made him an excellent candidate for White Dove.
White Dove, as Mark explains, was created 20 years before. Mark had been a director of the antiterrorist branch at the CIA. "That time we realized, I mean I realized that we started relying too much on technology. Soon we would have lost the old fashion way of gathering intelligence. We had to go back to using humans and not satellites. I thought it was high time to put back in the field agents that could become part of the place and gather information that we could not get just using satellites, internet or drones. It was given presidential order to create the White Dove branch. It was kept secret, only the President and the Director were aware of the project. We started recruiting special people some of them from different universities in the world. We selected each one of them because of their peculiar skills. I do not want to enter into details. We trained them and we sent them out. The organization was waterproof I was the only one they knew. None of the operative knew any of the others."
Apparently, though, a subsequent Adminstration had different thoughts on such matters and White Dove was ordered shut down, its people released. Now it is back and Webb, now 44 years of age, has been asked back.