One of the Knights of Wundagore, Lady Vermin fought alongside the Knights depending on her wisdom rather then size to fight her battles. She was ultimately killed by the mutant named Feral, who ate her alive.
During the late 90s animated series, Spider-man Unlimited, Lady Vermin was one of the Knights of Wundagore on the plant that was assigned to tracking down Spider-man. It was revealed she had an attraction towards him. She was not actually simply a smart rat in this series, and was more like a female version of Vermin (in the sense she was a bipedal humanoid rat)