“Star Wars: The Clone Wars” does a great job of exploring Dathomir’s culture, the abilities of the Nightsisters, and the nature of their Force magick. It also explains why we don’t hear much from them during the events of the Galactic Civil War decades later. Count Dooku’s (Corey Burton) former Sith apprentice, Asajj Ventress (Nika Futterman), is nearly killed by him and narrowly escapes to her home of Dathomir. There, the Nightsisters hatch a plan to assassinate Dooku, but it goes awry. In retaliation, Dooku sends General Grievous (Matthew Wood) and legions of Separatist battle droids to the planet to eliminate Ventress and her fellow Nightsisters.
Try as they might, Mother Talzin and her forces are unable to turn the Separatist army away. They’re massacred, and their home is destroyed, with a mere few survivors — including Talzin and Ventress — escaping the carnage. Talzin is later killed by Grievous, effectively ending the Nightsisters’ reign over Dathomir. All along, the mastermind behind the Separatists and the Clone Wars at large, Darth Sidious (Ian Abercrombie), saw Talzin’s magick as a threat. He knew that she had the power to derail his plans for galactic domination, so he made it his mission to remove her from the board before his Galactic Empire came to fruition.
Their magick may have given them momentary strength, but in the long run, the Nightsisters’ mastery of the Force-related power led to their downfall.