The Silent Guardians!
A beautiful and imperious woman, Black Mamba is a co-leader of the Serpent Society. She is surrounded by shadows that seem to move of their own accord, and is presumably proficient at employing them as weapons. In addition to her black and green outfit, Black Mamba also wears a group of four snakes.
Black Mamba led the Serpent Society, a group of super villains, on the mission to Guthrie Mansion to retrieve the plans to the OrBot for the Mad Thinker. There, the Society met humiliating defeat at the hands of the Silent Guardians. Only Black Mamba managed to escape, and she has vowed revenge against the Guardians. And then she got beat at the warehouse in St. Louis. It seems as if the Silent Guardians just have her number.