Auguste Lupa is a freelance agent.
Lupa is, as does not come as a surprise, is an alias. It is one of many that this interesting man has used before we meet him in the first of the two recorded adventures we have of him. He has used several in the past and will use others in the future, including one which will make him incredibly famous and renown many years down the road. One of his conceits is the practice of often choosing as his first name one used by a Caesar of Roman times. When we meet him, he is, of course, using that of the first Emperor. When he finally settles down for good a couple of decades later, he will go by Nero.
We learn eventually his birth name and with it his origin. That name is John Hamish Adler Holmes. The first two parts come as an homage to his father's best friend, Dr. John Hamish Watson. The third comes from the last name of his mother, the redoubtable Irene Adler. And the last comes from his father, the famous consulting detective Sherlock Holmes.
When we encounter him, the year is 1915 and Lupa is working ostensibly as a chef. His skills in the kitchen are already starting to be talked about in high society as he has shown that he is a master when it comes to food preparation. His ever so increasing waistline also shows his appreciation for his handiwork as well as that of his colleagues. Lupa loves fine food and at 25 years old, he has taken to spending a fair amount of his time planning, preparing, and consuming it.
But eating is by no means the only thing that interests Lupa for he will show an amazing talent at the far less showy business of espionage. A good agent must be able to listen to what is being said and not being said. He must be able to ask probative questions to dig out tiny morsels of intelligence. He has to be able to extrapolate whole truths when only partial admissions are given. Lupa is a genius at this.
Considering the genes he inherited from his parents, it is not surprising that Lupa is so good at his real job of freelance operative. While he would spend a fair number of summers living with and learning from his father, from whom he will gain the skills of detection he uses so well, most of his early learning came from his mother with whom he travelled throughout Europe before her death.
Lupa's skills as a detective are clearly shown in the first adventure when he is enticed to join a series of get-togethers to sit around and talk, invited by French operative Jules Giraud. Talking is something Lupa loves to do and drinking beer is something Lupa loves even more. [Considering his penchant for fine foods, it is interesting his preferred beverage is beer, not wine.] The poisoning of one of the members of this clique will pull from Lupa his talent for finding murderers as well as push him into an espionage case.