David Shafron, codename Ariel, is an agent with Mossad.
More specifically for the first trio of adventures we follow him on, he is a member - leader, really, of a specialized group in the Kidon, otherwise known as the eliminations department. They are the people called when it is decided the best way to handle a particularly difficult problem is to just eliminate it. Quick, sure, efficient. Legal? No but then again in the world of survival against sworn enemies of Israel who would do anything at anytime to wipe her from the map, the agents of the Kidon do not worry about legalities. Most of these assassinations are in other countries so it is vital for the sake of the operative sent to do the wet work that that person, man or woman, be trained in not only efficient killing but also ways to elude capture afterwards. It is best if undetected but since that is never for certain, evasion is taught. Shafrom - Ariel - is the best.
We actually meet Ariel - Shafron - in a very short encounter in the first adventure of a fellow Kidon operative known as . In a few short passages we find that he was the best operative in the Kidon who was her trainer, then her mentor, then her handler, and then, totally against regulations, her lover - her idea at first but he definitely did not put up a fight. She described him as "his features were too imperfect, a touch too rugged and worked. Black wavy hair worn longish, a nose that was a trifle too large, but a sensuality to his lips that she knew was genuine and eyes that she could get lost in for weeks. We never learn his full name in these mentions but we are told that his codename is Ariel and his first name is David.
The adventures we are allowed to follow Shafron on fall into two parts. The first is a trilogy of missions when he was still fairly new to the business, although already a force to reckon with. The second is many years later when he had moved out of the Kidon and become a right-hand man to the head of Mossad. His execution days might be behind him in that second adventure but his walking into trouble and having to fight his way out are not.