Viscus was a male Dathomirian Zabrak who led a Nightbrother clan on Dathomir during the Clone Wars and the early reign of the Galactic Empire. Though he was the leader of a Nightbrother clan, Viscus, like all the Nightbrothers, was subservient to the Nightsisters and their leader, Mother Talzin. During the Clone Wars, Brother Viscus aided Talzin in her fight against the Sith, first by supplying the Nightsisters with a warrior from his village to use in their plot to kill the Sith Lord Dooku. Dooku retaliated by having the Sith-led Confederacy of Independent Systems massacre the Nightsisters, after which Viscus allied with Talzin and her son Maul in their bid to exact revenge.