Asajj Ventress was a female Rattataki Dark Jedi and arguably the most dangerous of Count Dooku's Dark Acolytes. In actual fact, Ventress was trained as a Jedi, while a child on her home world of Rattatak, under the tutelage of Jedi Knight Ky Narec. However, after Narec was slain, Ventress gave into her anger and began walking the path of the dark side; taking up the lightsaber of her dead master, she trained herself in the Niman/Jar'Kai style of lightsaber combat, before slaying all the warlords on Rattatak and installing herself as its ruler.
Eventually, Ventress's actions came to the attention of Count Dooku, and after a test of her abilities, she became a commander in the Confederacy of Independent Systems. During the Clone Wars, Ventress became one of the most feared beings in the galaxy, notorious for her defeat of several Jedi. As the war continued, Ventress became the bitter enemy of both Jedi Knight Anakin Skywalker and his former mentor, Jedi Master Obi-Wan Kenobi, the latter of which was convinced that she could be redeemed. During Kenobi's mission to return Ventress to the light, she received a life-threatening wound from Skywalker, faked her death and disappeared into the unknown; wishing to be free of the Jedi, the war and Count Dooku.