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
Adventures of Captain Marvel Tom Tyler did not sufficiently resemble the "beefy, baby-faced Captain Marvel". At the time, Tyler was a weightlifting champion and the serial costume matched Captain Marvel's original comic book appearance, right down to his being slender. By the time of the serial's release, the appearance of Captain Marvel had changed due to Fawcett comics artist C. C. Beck having taken over drawing the character. Tyler was described as clumsy, knocking over props with his "lanky arms". Punches in fight scenes would sometimes connect. Due to his convincing performance in "King of the Royal Mounted", actor Robert Strange (as John Malcolm)