John D. Rockerduck, usually simply referred to as Rockerduck, is one of Scrooge McDuck's main business rivals. Created by Carl Barks in the comic. Voiced by John Hodgman.
Rockerduck, created by Carl Barks as a one-shot character, was picked up by foreign writers and made into their version of Scrooge's arch-nemesis and business rival, and thus said to be the "second-richest duck in the world".
Some old comics even had Scrooge and Rockerduck be born on the same day. However, it should be noted that in Rosa's Raider of the Copper Hill, Rockerduck is shown to be at least ten years younger than Scrooge, and by extension Glomgold.
Rockerduck is a shrewd businessman and has managed to organize a worldwide financial empire that can easily rival those of Scrooge and Flintheart Glomgold. Unlike them, he is not a tightwad but much more a liberal spender, preoccupied with showing his wealth to other people by buying expensive items and living an extremely luxurious lifestyle.
In The Outlaw Scrooge McDuck! Rockerduck makes his debut as a wealthy business man who in public presents himself as honorable and charitable. But in actuality, he is a con artist who swindles small towns into giving their town deeds over to him with a false hope of saving their town's low awareness and bringing in better profits. In most cases his schemes have not only brought him personal wealth, but have also brought the downfall of numerous small towns, leading them all to become ghost towns.
In Moonvasion! Rockerduck is revealed to still be alive and a member of F.O.W.L. His body is cryogenically frozen in an ice cube and is moved by his servant Jeeves who is nearly dead.