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
X-Men (comic book) X-Men (comic book) X-Men is a comic book ongoing series a namesake team of superheroes, published in various incarnations by Marvel Comics, beginning in 1963. The first series was eventually renamed "The Uncanny X-Men" with issue #114 (October 1978). In 1991, a second, companion series debuted, marking the first time, that more than one "X-Men" series would be published. This series took the simpler, earlier name "X-Men", thought it would later be titled "". Volume 3 began publication in September 2010 and for most of its run featured team-ups between the X-Men and other Marvel characters, ended at issue #41