Although they share a similar manic and chaotic personality, they are distinct characters with separate backstories and families.
* Daffy Duck hails from "Duckburg" (though not the same one as Donald's) and often claims to be "a duck of distinction." He has been seen with a wife and kids in some cartoons, though their appearances are sporadic.
* Donald Duck lives in Duckburg with his nephews Huey, Dewey, and Louie. His family is more prominent in his stories, and he often interacts with his uncles Scrooge McDuck and Ludwig Von Drake.
While they are not related in the fictional universe, their similarities make them a dynamic duo when they appear together.