The Raven Group is a private intelligence organization.
It was started just a few years before the first recorded adventure by Luke Raven, an elusive though not exactly reclusive tech billionaire. It pretty much takes on whatever assignments its leader decides either interest him or seem too compelling to pass up. The money it gets paid by the American government more than covers its expenses but considering how extremely rich Raven is, money is definitely not the issue.
Raven Group is not a small outfit, having lots of agents all over the planet but listed below are the main participants.
Luke: A genius with an almost insane IQ. In school, he showed at an early age just how brilliant he was. "By the time he was in his early twenties, he had three PhDs. Most degrees he read the books once, wrote the papers, never studied, and laughed at the questions. He aced the answers and spent the majority of his time imagining things no one else even thought was possible. He promised his dad he would never enter the Military. But Luke was powerful and competitive. When the Government heard about Luke, they wanted him for his ability to solve problems. He agreed to help but on his terms. His first request: he insisted on going through Navy SEAL BUDS training. Although he would honor his promise to his father and not make the military a career. He was unbeatable under water and the best shot the Navy had ever seen". Luke had been married with a young daughter but they were killed in a diving accident. After that, he created the Raven Group and has devoted his every moment to it in their honor.
Lorena: a 36-years old ex-FBI agent who joined a task force to hunt Bin Laden after her firefighter husband had died in 9-11. After that mission was successfully completed, she stayed with the Agency for a short time before being lured to the Raven Group where she is now one of its leaders.
Zach: an extremely experienced Navy SEAL who had been one of the men on the task force that took down Bin Laden. It was thought by several, though never acknowledged by him, that he was had pulled the trigger. After the notoriety had gotten too much, he gladly left the military to become the top agent with the Raven Group.
Samaar: codename 'Luci', a highly trained and ultr-deadly former Mossad assassin. Born and raised in Israel though she spent her teen years at boarding school in the U.K., Samaar joined the Israeli army as soon as she was able to find a way to get some revenge for the deaths of her parents from a suicide bomber. "The Israeli Special Forces heard about the angry Israeli girl who returned from London and wanted revenge. Then the Mossad heard rumors of how damaged I was and rushed in and claimed me." Now the mother of a 4-yr old named Alice, Samaar has left the business but unfortunately for her, she made a lot of enemies in the organizations whose leadership she eliminated and all of them have long memories.
Of all those mentioned, and many others in the Raven Group, the most deadly is Samaar/Luci.