The Femizons are the women who rule the powerful nation of Femizonia, an alternate future reality (the dimension of Earth-715). The most notable of which is Thundra, who inadvertently found herself cast to Earth where she became a member of the Frightful Four and, later, a hero and associate to the Thing.
When the super-villainess Superia learned of Femizonia, she came to believe that she was the ancestor of Thundra and became determined to bring about this alternate future within her lifetime. To this end, she secured an island to be dubbed Femizonia and sponsored a pleasure cruise for female super-criminals of all kinds. Superia called the women who arrived her Femizons, and intended to launch missiles from the island in order to infect the rest of Earth with a biological weapon designed to sterilize all other females. Surrounded by the island's protective dome, Superia and the Femizons would be unaffected, thereby granting them a powerful bargaining position over the rest of the planet-- Superia planned to force nations to submit to her, or face extinction. However, Captain America had tracked the cruise ship as he pursued his girlfriend Diamondback (Rachel Leighton), and the mercenary Paladin accompanied him. Captain America was unable to prevent the missiles from launching, but he tricked Superia into fighting him near the dome so that it would be damaged, forcing her to destroy the missiles herself.
After this, Superia operated with a smaller team of Femizons-- Blackbird, Iron Maiden and Snapdragon, although they were used mainly as her bodyguards. Superia journeyed to A.I.M. Island (Boca Caliente) during one of A.I.M.'s weapon expos and attempted to kill their CEO Alessandro Brannex and claim their resources for herself, but Brannex proved to be the Super-Adaptoid, and what's more, Captain America was on A.I.M. Island, helping Diamondback track Snapdragon, who had nearly drowned Diamondback during Superia's cruise. With her plans disrupted, Captain America mistook Superia for Diamondback, and wound up saving her from MODAM. Superia apparently disbanded the Femizons after this encounter.