Thaddeus Bodog Sivana is a fictional character appearing in American comic books published by DC Comics. Created by Bill Parker and C. C. Beck, the character is a recurring enemy of the superhero Captain Marvel, who first appeared in Whiz Comics #2 by Fawcett Comics. A mad scientist and inventor bent on world domination, Sivana was soon established as Captain Marvel's main archenemy during the Golden Age, appearing in over half of the Fawcett Captain Marvel stories published between 1939 and 1953.

Captain Marvel, also known as Shazam and the Captain, is a superhero in American comic books originally published by Fawcett Comics and currently published by DC Comics. Artist C. C. Beck and writer Bill Parker created the character in 1939. Captain Marvel first appeared in Whiz Comics #2, published by Fawcett Comics. He is the alter ego of Billy Batson, a boy who, by speaking the magic word "SHAZAM!", is transformed into a costumed adult with the powers of superhuman strength, speed, flight, and other abilities. The character battles an extensive rogues' gallery, most of them working in tandem as the Monster Society of Evil, including primary archenemies Black Adam, Doctor Sivana and Mister Mind. Billy often shares his powers with other children, primarily his sister Mary Batson and their best friend/foster brother Freddy Freeman, who also transform into superheroes and fight crime with Billy as members of the Marvel Family, also known as the Shazam Family.