Dondon grew up as a thief on the streets of Calimport. He used his halfling size and voice to disguise himself as a human boy in order to trigger the sympathy of his marks. He became one of Calimport's "most skilled con artist," but because he was so well known locally, he only preyed on foreigners. He lived in the Coiled Snake and often worked the Rogues Circle.
During the absence of both Entreri and Regis, Rassiter turned Dondon into a wererat in order to gain his loyalty. Dondon tried to lure Entreri into an ambush when the assassin returned to Calimport, but Entreri saw the truth and Dondon admitted that he greatly resented his condition.