Count Dooku was a menacing Sith Lord and central figure in the Clone Wars. Once a Jedi -- trained by Yoda -- he became disillusioned with the Jedi Order and thirsted for greater power. Dooku voluntarily left the light side behind and became Darth Sidious’ dark side disciple, taking the secret name Darth Tyranus and leading the Separatist army. Dooku advanced Sidious’s secret plot to take over the galaxy, but forgot that betrayal is the nature of the Sith.
Savage Opress was once a common Nightbrother whose fighting prowess impressed Asajj Ventress. Transformed into a monstrous warrior by Mother Talzin, Opress became Count Dooku's new assassin and secret Sith apprentice. His loyalty, however, remained to Talzin. The Nightsisters leader gave Savage a new quest: to find his brother, Darth Maul, who had somehow survived his apparent death and was living in exile in the Outer Rim. Savage located Maul and became his brother’s enforcer in the Shadow Collective, but died when Darth Sidious confronted the two Sith warriors on Mandalore.
Conniving even for Phindian standards, Moralo Eval earned a loathsome reputation as a heartless murderer at a young age. As a boy, he killed his mother, telling authorities he did it because he was "bored." A lifetime spent as a criminal and a fugitive gave Eval a sharp survival instinct, and he had impressive technical and engineering skills. Life on the run may have also left him deranged; Moralo's odd mannerisms included talking about himself in the third person. During the Clone Wars, reports surfaced that Moralo was working with Count Dooku, possibly plotting to kidnap Chancellor Palpatine.
An assassin trained in the ways of the dark side by Count Dooku, Asajj Ventress yearned to be considered a true Sith, but such status wasn't allowed under the Sith's Rule of Two. Ventress fought with twin red-bladed lightsabers, and clashed with Obi-Wan Kenobi and Anakin Skywalker many times. But her destiny would not lie with the Sith. After Dooku rejected her as his apprentice and tried to kill her, Ventress returned to her roots as a Nightsister, made a living as a bounty hunter, and – in the strangest twist of all – rediscovered the way of the light that she’d rejected long ago as a Jedi Padawan.