The Black Crow is an agent of British Intelligence.
We follow him through a handful of adventures which all take place during the Second World War as he literally leaps into the mouth of danger by parachuting in German-held lands to provide assistance to those fighting the invaders.
We learn very little about the Black Crow. We never even learn his real name as he is only referred to by that codename. We can tell from his depiction that he is a very good looking man in excellent physical condition, likely in his late 30s or early 40s. His grasp of foreign languages must be exceptional for he is able to converse with the resistance forces with no trouble and his skill at impersonating a German soldier clearly shows his knowledge of that language to be very good.
While it is unlikely that the Black Crow went about the business of making himself the nemesis of a Nazi officer by the name of Major Klaus von Steutsel, he most definitely did so. Of the Black Crow, von Steutsel is quoted in the first adventure, "That accursed Englander twists my very soul and haunts my every dream". He has good reason for his feelings. We are told that nine months before that initial tale, the Black Crow first made himself known when he landed in German-occupied territory and formed a resistance group. Numerous raids were made by this new squad and after each attack, the Black Crow left behind a calling card with the emblem of the Nazi Swastika on which is standing a black crow. He also left a long, very nasty looking jagged scar on von Steutsel's left side of his face.
We do not have that many adventures of the Black Crow. It is unknown if he met his doom sometime after our last recorded mission or if his continued actions were simply not as well known.