Even the 20th-century cousin to Superman, Supergirl, was recruited as a member. In "Adventure Comics" #300 (September 1962), the Legion received their own regular feature, cover-billed "Superboy in 'Tales of the Legion of Super-Heroes'". While they would share space with Superboy solo stories for a couple of years, they eventually displaced Superboy from the title entirely as their popularity grew. Lightning Lad was killed in "Adventure Comics" #304 (January 1963) and revived in issue #312 (September 1963). It was the "Adventure Comics" run which established the Legion's general workings and environment. A club of teenagers, they operated out of a clubhouse in the shape of an inverted yellow rocket ship which looked as if it had been driven into the ground. The position of Legion leader rotated among the membership. Each Legionnaire had to possess one natural superpower which no other member possessed; despite this, several members had overlapping powers, particularly Superboy, Supergirl, Mon-El, and Ultra Boy. Some issues included comical moments where candidates with bizarre, useless, or dangerous abilities would try out for membership and be rejected; five of these flawed candidates went on to form the Legion of Substitute Heroes. The Legion was based on Earth and protected an organization of humans and aliens called the United Planets alongside the regular police the Science Police. The setting for each story was 1000 years from the date of publication. In "Adventure Comics" #346 (July 1966), Jim Shooter, 14 years old at the time, wrote his first Legion story. Soon thereafter, Shooter became the regular writer of the Legion stories, with Curt Swan, and later Win Mortimer, as artist. Shooter wrote the story in which Ferro Lad died—the first "real" death of a Legionnaire (although Lightning Lad had been believed dead for a while before)—and introduced many other enduring concepts, including the Fatal Five, Karate Kid, Princess Projectra, Shadow Lass, the Dark Circle, Mordru and the "Adult Legion", a conjecture regarding what the Legionnaires would be like when they grew up. The Legion's last appearance in "Adventure Comics" was #380 (May 1969), and they were displaced by Supergirl in the next issue. The early 1970s saw the Legion relegated to the status of back-up feature. First, the team's stories were moved to "Action Comics" for issues #377–392 (June 1969 – September 1970). Following Mort Weisinger's retirement from DC, the Legion was passed to the oversight of editor Murray Boltinoff and began appearing occasionally as a backup in "Superboy", starting with #172 (March 1971), with writers E. Nelson Bridwell and Cary Bates and artist George Tuska.