Early Contenders:
* Mandrake the Magician (1934): While not technically superhuman, Mandrake possessed mystical powers and could perform feats of incredible strength and illusion.
* The Phantom (1936): Similar to Mandrake, The Phantom relied on skills, gadgets, and knowledge to appear superhuman.
* Superman (1938): This is the most widely recognized answer. Superman's Kryptonian origins gave him truly superhuman powers, setting a precedent for the superhero genre.
Arguments for Other Characters:
* The Shadow (1931): While primarily known for his detective skills, The Shadow's abilities were attributed to hypnotic suggestion and a mastery of martial arts, which could be argued as superhuman.
* Doc Savage (1933): A pulp fiction hero, Doc Savage possessed superhuman strength and intelligence, along with advanced scientific knowledge and a unique blend of skills.
Conclusion:
While Superman is the most recognized answer, the question remains open to interpretation. Ultimately, it depends on what criteria you prioritize when defining "superhuman abilities" and "comic book character."