who are the duke and the king

The King

The elder of the two con men with whom Huck is forced to travel. He plays the naked man in the Royal Nonesuch and is the man who sells Jim as a runaway slave. He is later tarred and feathered along with the Duke.

The Duke

The younger of the two con men and the man who invents the Royal Nonesuch. He is later tarred and feathered in Pikesville.

Both Men are unsympathetic characters. At first they seem rather harmless comic relief but their hijinks become insidious as Twain unfolds their characters.