Betty Barstow, the secretary to private detective Dan Hurley, is on her way to a costume ball when she decides to investigate a crime her boss didn't want to look into. She's wearing a superhero-style costume and when she encounters crooks and uses her jiu-jitsu skills to beat them, she comes off as a superheroine, and so she decides to make a practice of fighting crime. In the modern era she was brought back. In Invaders she was shown using recently-acquired armor to help The Invaders against the Battle-Axis during World War II, for which she was made an honorary member of the Invaders before becoming a founding member of the current V-battalion. She is still active with V-Battalion today but is suffering from the early stages of Alzheimer's disease.
Her creation isn't totally clear. She was created in part by Harry Sahle, but others may have had their hand in, as well.