Star Wars: The Clone Wars - Season 3 - Eps 13: Monster
When Count Dooku calls upon the Nightsisters seeking a replacement for Ventress, she and her kin seize the opportunity to exact revenge. Ventress visits the far side of Dathomir and the males of the planet seeking the most brutal and powerful warrior among them. Talzin has Asajj secretly select a warrior from the distant Nightbrother village: Savage Opress. With the power of dark magic, Talzin transforms Savage into a hulking warrior ultimately loyal to Asajj. She then delivers Opress to Dooku, where he will serve as his secret Sith apprentice in a plot to overthrow Darth Sidious.
About Star Wars: The Clone Wars

Title: Star Wars: The Clone Wars
First Air Date: 2008-10-03
Last Air Date: 2020-05-04
Status: Ended
Rating: 8.5/10 (from 2106 votes)
Language: EN
Seasons: 8
Total Episodes: 133
Network: Cartoon Network Netflix Disney+
Genres: Action & Adventure, Sci-Fi & Fantasy, Animation
Production Companies: Lucasfilm Animation, Lucasfilm Ltd.
Synopsis
Yoda, Obi-Wan Kenobi, Anakin Skywalker, Mace Windu and other Jedi Knights lead the Grand Army of the Republic against the droid army of the Separatists.
Cast

Ashley Eckstein
Ahsoka Tano (voice)

Matt Lanter
Anakin Skywalker (voice)

James Arnold Taylor
Obi-Wan Kenobi (voice)

Dee Bradley Baker
Clone Troopers (voice)

Tom Kane
Yoda / Wullf Yularen / Narrator (voice)