A dangerous spy agent for the axis powers during World War 2, Mr Banjo would transmit massages coded into the tunes he played on his Banjo while pretending to be a busker.
He was described as a "...a master criminal, an ingenious plotter of crimes — a fiend who would snuff out life as easily as he would blow out a candle." After his first scheme was foiled by Captain Marvel, Mr Banjo returned to kidnap President Roosevelt and replaced him with an imposter.
His scheme was foiled again, and after being tried for war crimes, he later joined the Monster Society of Evil, despite not being a monster and being armed only with a banjo. His time with the society was short lived, after one skirmish he was not seen again.