Edward Whelan was a geneticist who became interested in the works of Armin Zola. Searching for Zola in Mexico, Whelan was captured and experimented on by Baron Zemo. They turned Whelan into the cannibalistic rat-man Vermin and sent him to New York to attack Captain America. Vermin was defeated in this battle and soon rebelled against Zemo’s orders, choosing to live in the sewers. Following a brutal beating at the hands of Kraven the Hunter, Vermin reverted back to his human form for a time and began helping at the Ravencroft Asylum. However, he has now returned to his man-rat form and has since been arrested.
Vermin possesses superhuman strength, speed and agility as well as an enhanced sense of smell. His nails and teeth are razor sharp and able to rend wood and soft metals. Vermin can communicate with and command all rats and dogs within a 2-mile radius, but it is unknown whether this ability is hypersonic or telepathic in nature.