The Nightsisters, also known as the Witches of Dathomir or Daughters of Dathomir, were a clan and ancient order of magick-wielding female Dathomirians who lived on Dathomir, a planet bathed in dark energies. These Dark side users were able to perform their arcane magicks by tapping into the magical ichor that flowed from the depths of their planet.

The Nightsisters were created by Dave Wolverton, and first appeared in his Star Wars Legends 1994 novel The Courtship of Princess Leia. In Legends, they are depicted as a splinter faction of the native Witches of Dathomir; descendants of the fallen Jedi Allya and appeared in multiple Legends works. Wolverton himself noted in an interview that he sought to create a set of powerful female figures in the Star Wars universe that had been dominated by men at the time, and expressed delight that the concept was picked up by George Lucas for his backstory of Darth Maul.

George Lucas later decided to integrate them in his TV series Star Wars: The Clone Wars after he saw Lucasfilm Animation Singapore‘s use of the Nightsisters in the video game Star Wars: The Clone Wars: Jedi Alliance (2008), and how they were inspired by a concept art by Iain McCaig for The Phantom Menace. They were first introduced in the current canon with the twelfth episode of the third season, «Nightsisters,» aired on January 7, 2011.

Tricia Barr, author of the 2018 reference book Star Wars: The Dark Side, extrapolated from source material that the Nightsisters had enough magick and technology to reproduce without the necessity of the Nightbrothers.