Sith Training Droids were a part of an advanced series of holodroids based on the design of the prototype unit known as PROXY. Constructed on the vast ocean-covered world of Kamino, the training droids were primarily used as instruments in a secret project conducted under the surveillance of the Sith Lord Darth Vader. Following the redemption and death of his former apprentice, Galen Marek, Vader was determined to create a "new Starkiller" by utilizing the experimental advanced cloning process.