Lord Starkiller

Lord Star Killer or Darth Starkiller was a version of Galen Mark if he decided to kill Darth Vader in the Force Unleashed:I

How to become lord Star Killer
On the final level of The Force Unleashed I, stop and turn to Vader when you have a choice in who to confront -- Darth Vader or Darth Sidious. Jump down to the seriously wounded Vader and then he will attack but you can kill the Sith lord without much difficulty. After Vader dies you will confront Palpatine and he comments on how lord Vader failed all along and orders you to slay master Kota. You pretend to obey the lord but instead the dark lord knew your strategy. Then the Rogue Shadow shows up, but Palpatine grabs the Rogue Shadow through the Force and throws it at you killing Juno, Bail Organa and the other senators. You then awaken to discover your body completely reconstructed into a Sith Stalker suit. and you become the Emperor's apprentice

Endor
See Dark Apprentice