Sometimes called the "Napoleon of Crime," who was Sherlock Holmes' arch rival?

Sherlock Holmes himself bestowed the title "Napoleon of Crime" upon this formidable adversary, a man he considered his absolute intellectual equal. While maintaining a public facade as a respected mathematics professor, this character was secretly the mastermind at the center of a vast and intricate web of organized crime that plagued London. Author Arthur Conan Doyle created him specifically to be the ultimate challenge for his brilliant detective—a villain whose genius and cunning could rival Holmes's own.

The character was famously introduced in the short story "The Final Problem," in which Doyle intended to kill off both the hero and the villain in a dramatic struggle at the Reichenbach Falls. Though public outcry later forced Doyle to resurrect Holmes, the professor's place in history was cemented. Despite his limited appearances in the original canon, his shadow looms large over the entire series, establishing him as the definitive arch-nemesis.

This legendary rivalry has since become a cornerstone of countless film and television adaptations. On screen, the character is often given a much more prominent role than he had in the books, allowing filmmakers to fully explore the "battle of wits" between the two geniuses. Portrayals range from cunning and reserved schemers to unhinged and chaotic antagonists, but he remains the ultimate villain forever tied to the great (Review) detective of 221B Baker Street.