Alexander Armstrong is an agent for the American President.
Officially he is a Captain in the Army and we are told right away that he was a part of Military Intelligence and had been for several years, serving under the direction of a Colonel McCullough. Since his first recorded adventure, however, he is under the direct order of the Chief Executive, so it is seems more accurate to state him as being his operative.
Our first contact with Armstrong comes in late Spring of 1917, immediately after the sinking by a U-boat torpedo of the RMS Lusitania and the loss of 1100 souls. At the direction of President Wilson, Armstrong is sent on his first mission specifically at the behest of the Oval Office. Further adventures will be handled over the next decade under the orders of the same President or his successors.
One of the reasons Armstrong was singled out for the initial mission was his native grasp of both German and Arabic. He recounts how as a young boy growing up in Wisconsin the son of an Irish father and a German mother, became friends at age five with a neighbor who was from the Middle East.
The neighbor had "an assortment beautiful books written in Arabic. When I showed an interest in what the writings meant, he began teaching me some basic words in the language. I picked it up quickly, so day by day he taught me more. When my mother found out I could read and even speak some Arabic she insisted I learn German so I could write to our relatives in the old country. By the time I was ten, I seemed to know both languages as well as I knew English."
Armstrong is single with no immediate prospects in the love department but his travels will open a few avenues.