David Logan is an agent with the CIA.
Nahbi Adler is an agent with Mossad.
Tiera Aquilina is an agent with MI6.
The three recorded adventures we have of these two are promoted as the Nahbi Series but Logan has, IMHO, a bit more prominence in the activities so I have given him top billing. As will be explained below, Nahbi, though, is the more unique individual and for that reason likely given his titular position. Aquilina comes a very close third in this hierarchy.
First the facts on Logan.
Raised by his grandparents in a "conservative and deeply religious home" in Texas, Logan graduated from Baylor with a BA in linguistics, being fluent in Hebrew, Arabic, and Farsi, going on to earn a master's in theological studies. He joined the army after college, qualified as an expert marksman before heading to OCS to become a 2nd Lt. Afterwards, he was trained in Urdu and Pashto followed by a tour in Afghanistan. His tour ended after a half dozen months when an IED killed most of his recon patrol and mangled a leg so badly he has trouble with metal detectors. He would then go on to earn a PhD in Semitic Languages from Cambridge University before going to work for the CIA.
He is described as a handsome man, having brown eyes with gold flecks in them, and an "obvious masculine virility".
And now the data on Nahbi and why he is so unusual.
Nahbi is an android, "a type of advanced robot designed to be indistinguishable from a human being without close examination". Who designed or constructed him is unknown to us when we first meet him and to him. His first memories were being 'awakened' in the "City of Jerusalem in what your modern calendar system would refer to as the year 60 AD". At that time he was being deeded to a major figure in the Great Sanhedrin by a mysterious merchant named Amun. How he came to exist and why this Amun was determined that he be placed in that household is a tad mysterious and needs to be read to be understood. The important fact here is that he would soon be given the mission of tracking down and assassinating a man. "I was ordered to follow the Christian zealot you know as the Apostle Paul and to kill him before he reached Rome. I was a passenger on the Gaius Oceanus when it sank. It was an Alexandrian merchant ship bound for the empire's maritime hub at Portus, fifteen miles southwest of Rome. I went aboard in the port city of Caesarea. I was trying to catch a man before he reached Rome. Unfortunately, he left port two days before I did. When the ship sank in an early winter storm, I was unable to complete the task my master had given me".
Two thousand years later, a vacationing Logan along with his girlfriend Tiera Aquilina were diving in the Mediterranean, they discovered the perfectly preserved humanoid "buried in sand near the remains of a very old wooden merchant sailing ship." They brought him to the surface and were a bit astonished to find him 'alive'. They were further amazed, and highly sceptical, to discover him able to access their computers and to learn in a short few hours English and other modern languages.
Like I said. Unusual.
Lastly, Aquilina "twenty-eight years old. She's five feet five inches tall with luminous brown eyes and short, dark-brown hair. She's worked for MI6 for only a few months, but spent several months at MI6 the previous year as a member of Task Force 3. She has a PhD in computer science from Cambridge University, where she met David Logan. She speaks several languages fluently. As the sole surviving heir to the considerable wealth her father has amassed, she did not have to work anywhere to earn a living but her passions for justice drove her to join the SIS.
The three make a very interesting team.