Dark Jedi were Force-sensitives who were devoted to the dark side of the Force but were not Sith nor members of the Inquisitorius. One Dark Jedi, whose rise had been the object of a Jedi prophecy, was the daughter of an ancient duchess of Malastare. At least during her service to CountDooku and the Confederacy of Independent Systems, Asajj Ventress was considered a Dark Jedi.
The term «Dark Jedi» was originally coined by author Timothy Zahn for his 1991 Star Wars Legends novel Heir to the Empire as a label for a Jedi that had fallen to the dark side, as the term «Sith» still had yet to be officially defined. He later noted that the term became somewhat «squishy» and for this and other reasons was discouraged, though it was the best he and others had to work with at the time.