Four villains have dominated Batman's visual and narrative history since the 1940s: the Joker, the Penguin, Catwoman, and the Riddler. All four appeared between 1940 and 1948 and have never left the Gotham ecosystem since. Each embodies a specific psychological dimension of the Dark Knight: pure chaos for Joker, organized crime for Penguin, ambivalent seduction for Catwoman, narcissistic intelligence for Riddler. These four villains are also the ones who have had the most major film and television adaptations.

Beyond the four icons, a dozen major villains structure the classic Batman gallery. Each has its dedicated origin story, recurring arcs, and at least one significant film or video game adaptation. Together, they form what is known as Gotham's criminal ecosystem — a pantheon of characters as recognizable as the hero himself.

Beyond the main and classic villains, around twenty secondary antagonists enrich the Batman universe with their specific narrative depth. Many emerged in major comic arcs or cult animated series. They may not dominate the screen, but their presence gives Gotham its inimitable criminal density.

Some major villains in the DC universe go beyond the strict confines of Gotham and regularly encounter Batman as part of the Justice League or major crossovers. They are not exclusively Batman's enemies, but their clashes with the Dark Knight produce some of the most memorable moments in modern comics.

Some of Batman's enemies are not individuals but entire criminal organizations. These factions operate on a Gotham or global scale and represent structural threats that Batman cannot face alone. Understanding these organizations is essential to grasp the geopolitical stakes of several major comic arcs.