As the archenemy and "evil twin" of Darkwing, not much is known about Negaduck's place of origin. A possible clue is that he rules the Negaverse (an antimatter universe analogue) similar to Darkwing's home of St. Canard where evil reigns supreme. He refers to the Negaverse as his "secret hideout", which can only be accessed through a portal within the hollow shell of a papier-mâché cake inside a local bakery in the original St. Canard.
In addition to his own crimes, Negaduck is known to lead a band of villains he has dubbed the Fearsome Five, which also consists of Megavolt, Reginald Bushroot, Liquidator, and Quackerjack. Despite not having any powers of his own, he maintains an iron grip on the group's leadership through his intelligence and sheer ruthlessness.
Negaduck occasionally has taken advantage of the fact that he greatly resembles Darkwing Duck by attempting to frame his good counterpart by committing crimes while disguised as Darkwing. This once came back to haunt him after instigating the public to put a price on Darkwing Duck's head and an angry mob mistook him for Darkwing Duck in different clothes. He also takes pride in being known as Public Enemy #1 and was greatly incensed to learn that Dr. Slug had stolen the title from him, prompting him to go on a rampage in order to reclaim it.
Negaduck lacks any powers of his own but makes up for it with his sadistic temprament and penchant for destructive weaponry, i.e. chainsaws, flamethrowers, bombs, and even a nuclear missile.