Captain Marvel (DC Comics) Comics" #21 (1941) introduced the Lieutenant Marvels: three other boys named "Billy Batson" who could also become adult superheroes. Captain Marvel, Jr., the alter-ego of disabled newsboy Freddy Freeman, debuted in "Whiz Comics" #25 (1941). Mary Marvel, alter-ego of Billy's twin sister Mary Batson, first appeared in "Captain Marvel Adventures" #18 (1942). In contrast to Captain Marvel and the Lieutenants, both Mary Marvel and Captain Marvel, Jr. remained kids in superhero form, and were given their own eponymous books in addition to appearing as the lead features in "Master Comics" and "Wow Comics", respectively. Captain Marvel, Captain Marvel Jr., and
Captain Marvel (DC Comics) "The World's Mightiest Mortal", starting with "Shazam!" #15 (December 1974). As all subsequent toys and other merchandise featuring the character have also been required to use the "Shazam!" label with little to no mention of the name "Captain Marvel", the title became so linked to Captain Marvel that many people took to identifying the character as "Shazam" instead of "Captain Marvel". The "Shazam!" comic series began with "Shazam!" #1 (Feb. 1973). It contained both new stories and reprints from the 1940s and 1950s. Dennis O'Neil was the primary writer of the book. His role was later taken over by writers