Rumaan Harjavti

Rumaan Harjavti is a fictional dictator from DC comics and primarily an enemy of the Justice League, he is not officially a supervillain in the sense of lacking melodramatic costumes or abnormal abilities but is still a capable threat to even the Justice League in the fact he is a ruthless and powerful world leader, a type of villain not often faced by superheroes (save in times of war, such as when most of the Western World (including its superhero community) fought against Imperial Japan, the Soviet Union and (most infamously) the Axis Powers).

Rumaan himself is the ruler of Bialya and has vast resources at his disposal, which makes him just as dangerous as any crime lord - his political status also proves a problem as any attack against him risks sparking war, since he is the ruler of a country.

Trivia

 * Rumaan's position as a dictator to a nation is similar to Marvel's Doctor Doom, the fact that Doom is the ruler of a country has frequently made it difficult for Marvel's heroes to properly fight him out of fear of the political consequences of such actions