In the 1940s The Black Cobra was Jim Hornsby, a law clerk working in the office of his father, the local district attorney. He dressed up as The Black Cobra to fight crime for no discernable reason other than wanting to fight crime. His only adversaries he had were The Professor, his henchman Hugo, and the Hell Gang.
He had no special skills, gadgets or powers, just a good right hook and a pretty good costume.
Note: Starting out in Harry A. Chesler’s Dynamic Comic #1 in 1941 this Black Cobra only appeared in that one issue. Another Black Cobra has appeared at Ajax-Farrell's short lived Black Cobra comic book series in 1954 starring a different hero named Steve Drake and his has a sidekick called Cobra Kid. There is no core relation to either Black Cobras, nor any evidence suggesting that Steve Drake took up the mantle. Both Black Cobras in in public domain.