Dark Apprentice

The Dark Apprentice is Darth Vader's perfect clone of Galen Marek. He is truly the one and only clone loyal to Darth Vader. To complete his training it is revealed that Darth Vader let the playable Starkiller clone escape and have his clone kill him. It is shown that he did learn to hate Galen Marek's love interest as he looks at the dead body of Juno Eclipse for a moment, then proceeding to walk away. He is only seen in the Dark Side ending of Star Wars: The Force Unleashed II and his progress towards his journey towards the Dark Side is shown in the Distant Thunder cutscenes (you unlock these in the extras menu by completing the challenges)