Superwoman, the villainous counterpart from the Crime Syndicate of Earth-3, first appeared in Justice League of America #29 (August 1964), created by Gardner Fox and Mike Sekowsky. In her original pre-Crisis incarnation, she was an evil Amazon with powers similar to Wonder Woman's, including super-strength, flight, and a magical lasso that could change shape, serving as a member of the Crime Syndicate of America alongside Ultraman, Owlman, Johnny Quick, and Power Ring. This version portrayed her as a rogue from a parallel Earth where good and evil were inverted, often clashing with the Justice League across multiversal battles until the events of Crisis on Infinite Earths (1985) erased her reality.
Post-Crisis revivals began with the antimatter universe version in Grant Morrison's JLA: Earth 2 (2000), where Superwoman was reimagined as an Amazon who adopted the civilian identity of Lois Lane, married to Ultraman while secretly engaging in affairs with Owlman and others, wielding a lasso that released inhibitions rather than compelled truth, and occasionally displaying heat vision. The New 52 era (starting in 2013's Forever Evil by Geoff Johns) further developed her as a hybrid of Lois Lane and Wonder Woman origins, pregnant with Alexander Luthor's child (Mazahs), involved in complex romantic entanglements, and contributing to the Syndicate's invasion of Prime Earth.
In recent continuities following Infinite Frontier and events like War for Earth-3 (2022), Superwoman has appeared in varied forms, including a Donna Troy-based iteration on a rebooted Earth-3, maintaining her role as a manipulative, powerful antagonist within the Crime Syndicate while navigating shifting alliances and defeats, solidifying her as a symbol of corrupted Amazonian might and moral inversion in DC's multiverse.