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 this as one of the most outstanding of all serials and Republic's "masterpiece". He writes that Tyler's "striking performance...remains in thousands of minds as the most memorable serial hero of all time – bar none". The characters of Betty Wallace, Whitey Murphy, and John Malcolm all appeared in the Fawcett comics in the 1940s, beginning with "Capt. Marvel And The Temple Of Itzalotahui" ("Whiz Comics" #22, Oct. 3, 1941) featuring Murphy and Malcolm; Murphy made several appearances in the 1970s DC Comics incarnation of Captain Marvel, as featured in the comic series "Shazam!" and "World's Finest Comics". Fawcett also published