After the real Asajj Ventress redeemed herself and was killed by her dark master, Dooku decided to created a former clone of her, so the Jedi would believe she was alive. Dooku taught her the ways of the dark side, but he tries to keep everything secret,in order for his plan to work. He sent her on an important task on Bastion to exterminate Lyon Vil. Ventress killed Lyon, but this was not until Republic spies deliver this information about Ventress. Obi-Wan was shocked to see that Ventress was alive, but still corrupted to the dark side. Kenobi thought it was impossible because he remembered that Dooku killed in front of his eyes. Anakin believed she was clone, but Kenobi didn't believe it.
Throughout the battles, Kenobi wanted to find out some answers about Asajj Ventress' past. Looking at the Jedi records, he found out about her past. He concluded that Ventress was misled, not evil, and took it upon himself to find her and bring her back to the light. Anakin thought it was risky, but Kenobi wanted to try and redeem her to the light side of the force and for her to rejoin the Jedi Order.
After the cloned Ventress was badly injured, she was sent to the planet Boz Pity, where she was placed in a bacta tank by Count Dooku and given cybernetic modifications to amplify her rage. Dooku feared that his master will find out about his betrayal and decides to give her one final mission in order to be strong. She was to fight Obi-Wan Kenobi and Anakin Skywalker.
When Republic forces attacked Boz Pity, Kenobi came upon the chamber in which Ventress was contained within a Separatist facility, and was subsequently attacked by her when she detected him in her trance. She fought against both Kenobi and Skywalker, only to be unexpectedly abandoned by Dooku, who did not want her to delay his escape. He ordered an IG-100 MagnaGuard to kill her as she desperately tried to reach Dooku's shuttle. Using a blaster rifle, the droid shot Ventress down as she approached the shuttle.
Enraged and wounded, Ventress attempted to kill Kenobi, who was trying to help her, only to be dealt a mortal wound by Anakin. As she lay dying, Ventress told Kenobi to protect the Galactic Core from Dooku, and finally let go of her anger and rage. Perhaps, she mused, Kenobi had been right about her. She thanked Obi-Wan and gave him a kiss, showing that she redeemed herself back to the light. With that, Ventress appeared to die, and Obi-Wan ordered her corpse to be placed aboard a medical shuttle.
Despite appearances to the contrary, Ventress did not die. Her wounds were healed, but she was still weak. Ventress knew that the Jedi were helpful to her, and hopes tha one day she will see Kenobi again. She used a Jedi mind trick on the pilots and tells them to take them far away from the war.
Around 19 BBY, her whereabouts were located on Bastion. She lived a quiet life in the floating city until she read reports about the Jedi betraying the Republic and the Empire. Fearing that the Empire might find her, she leaves Bastion until she was confronted by Storm troopers. Asajj Ventress killed them, and took a transport to escape. Seeing a flashback of thr original Asajj Ventress who traveled to meet the witches, the clone sets course to Dathomir.
Mother Talzin welcomed Asajj Ventress, but she knew who she was. The clone was offered sanctuary when the Empire was spreading through the galaxy. Asajj Ventress decided to stay for a while until she remains undiscovered by the Empire. After Mother Talzin was nearly close to dying, Asajj Ventress was made leader of the clan. Talzin whispered to her, and told her that the galaxy must be restored.
Around 1 BBY, Asajj Ventress and the clan join the Rebel Alliance when they contacted Princess Leia Organa. Leia Organa thinks it was trick, but she decided to let them help. She later visited the Nightbrothers where she gathers strong warriors to fight against the Empire. Asajj Ventress became a great teacher, and taught the Nightbrothers how to defend themselves from Imperials. She later contacted Leia Organa when she was ready to bring in her forces to assist the Alliance.