Duke Duralumon is next in line to the throne after Sapphire. He is constantly trying to discredit Sapphire in order to inherit the throne. He is a fairly hands-off villain; he makes speeches to try to turn the people against Sapphire, but leaves the actual physical work of kidnapping and thuggery to his blackguard enforcer, Baron Nylon, and a gang of thuggish highwaymen known as the "Black Hats". Duralumon is corrupt and cruel and does pose a genuine threat to Silverland. Still, he is more of a bumbling, comedic villain than a sinister one. Later in the series he is shown to be a quisling in the employ of more seriously evil characters, such as Satan or Mr. X. Duralumon has a son named Plastic, whose primary function is to provide the series' comic relief on the villains' side.
- Duke Duralumon along with Baron Nylon will make a cameo appearance in Pooh's Silverland Adventure.