An alternate continuity, Darkwarrior's Universe was once an alternate timeline of the Prime Universe, and was the same as the Prime Universe in every way up until 1992, when Gosalyn Mallard, Megavolt, and Quackerjack were all sent to the future in Quackerjack's Time Top.
Darkwing Duck believed that Gosalyn had run away from him, and sunk into a depression, giving up crimefighting, until he managed to rescue a girl who reminded him of Gosalyn, leading him to realize that the world still needed a superhero. However, he decided that he had not been harsh enough in his crimefighting techniques before, and became a ruthless tyrant, taking on the name of Darkwarrior, creating lethal weaponry and conquering St. Canard with tanks and robots to prevent all crime, so as to ensure that no one else ever felt the same sense of loss that he did. Darkwarrior began to throw anyone who disagreed with his methods into jail (even firing his universe's version of Launchpad McQuack), and kill criminals even for the most minor of offenses.
This turned the St. Canard of Darkwarrior's timeline into something of a dystopia, although it can be assumed that much of the rest of the universe was left unchanged from the Prime Universe.
After the Time Top re-materialized in the future and Gosalyn saw what Darkwing had become, she traveled back in the Top and changed the past so that the events of Darkwarrior's timeline never came to pass, creating a new timeline from which the Prime Universe continued. However, Darkwarrior's timeline was not destroyed, instead branching off into a separate universe.
This universe was later visited by Negaduck and the Magica De Spell of the Prime Universe, who were hoping to hypnotize and kidnap Darkwarrior, as part of a plot to discredit the Darkwing of the Prime Universe and conquer his version of St. Canard. Unexpectedly, Darkwarrior agreed to come of his own accord, with no kidnapping or hypnotizing necessary. It is unknown whether any significant changes occurred in Darkwarrior's Universe while he was gone, although it is known that he returned soon after.
Interestingly, due to the circumstances of the universe's creation, Darkwarior's Universe was, technically, the Prime Universe at first, before the timeline was changed. Also interestingly, Gosalyn Mallard, Megavolt, and Quackerjack do not actually exist in Darkwarrior's Universe, at least in the present, as their disappearance was the branching point of Darkwarrior's Universe from the Prime Universe, and the versions of them that re-materialized in the Time Top were actually still the Prime Universe versions of themselves, later returning to the Prime Universe.