With Adventure Comics #381 in 1969, Supergirl migrated from the backup slot in Action Comics to the starring feature in Adventure and ran until issue #424.
Supergirl was introduced in 1959. A number of different characters have assumed the Supergirl mantle over the decades, with the most popular and enduring version of the character being Kara Zor-El, Superman’s cousin, who shares his super powers and vulnerability to Kryptonite. Supergirl plays a supporting role in various DC Comics publications, including Action Comics, Superman, and several comic book series unrelated to Superman. In 1969, Supergirl’s adventures became the lead feature in Adventure Comics, and she later starred in an eponymous comic book series which debuted in 1972 and ran until 1974, followed by a second monthly comic book series titled The Daring New Adventures of Supergirl, which ran from 1982 to 1984.