Jericho Black is an agent with The Box.
Well, if he really existed. And if the organization in question actually officially existed. In truth, the name 'Jericho Black' is actually the call sign used for Will Hessler after he was invited to go to work for The Box. Sound a bit confusing at first but it isn't, really.
First, a note about the Box. It is an Israeli department that does not exist. As it is explained to Hessler by the man who would become him mentor, Jacob Mitzak, the group is not "part of Mossad, and you won't find any trace of our existence in any official Israeli document. [People] simply refer to us as 'The Box'". Mitzak goes on to explain, "You put a problem in The Box and the problem goes away. Each intelligence service has their own version of The Box. The CIA refers to them as NOCs, for non-official operative cover."
Initially the primary objective of The Box was to hunt down and eliminate Nazi war criminals trying to remain hidden throughout the world. The purpose the The Box with regards to them was to be their killers - killers with purpose. "We aren't police or spies. We aren't trying to collect evidence or take people to court. By the time a name is passed to me on a busy street written on a slip of paper in invisible ink that name has already stood the test of some pretty heavy scrutiny. That name has done things, unimaginable and unspeakable things, and that name has been waiting a long time for a man like me to show up at its door and deliver upon it the wrath of the tribe of Israel."
That is the world that Will Hessler is entering when we first meet him.
Hessler, being American by nationality and not being Jewish by ethnicity, would seem a strange candidate to go to work for The Box. In fact, though, he comes to them with the same fervent hatred of the Nazi movement and its followers. His despise comes from a different source.
Hessler's grandfather was Franklin Hessler, a Nazi genius who had worked alongside Adolf Eichmann while in hiding after WWII. He managed to escape capture along with his family and to raise a daughter who believed in the Aryan cause every bit as intensely as her father. When she eventually gave birth to her own child, Will, she relentlessly indoctrinated him into that mindset.
It did not take as well as she might have thought. And when she took her hatred of Jews to an even higher level and bombed a synagogue, killing dozens and severely injuring Will Hessler's girl friend, she gave him an enemy to fight.
The adventures we have of Will Hessler/Jericho Black will follow him as he becomes more and more a spear in the defense of Israel, going up against Nazis like his mother as well as Islamic extremists. Enemies of his native America and his adopted Israel have a worth opponent in Hessler.