Galen Marek is played by Jerry and his PB is Sam Witwer.

Galen Marek was the son of Kento and Mailie, both Jedi living on Kashyyk.  His mother died defending the Wookies from slave traders.  After the Purge, Vader made a personal appearance on Kashyyk, looking for Kento.  He found him, and after a duel, killed him.  In the process, he discovered Kento's son, someone who, even at such a young age, was already extremely strong in the Force.  Vader saved his life when Imperial officers attempted to kill him, and trained the boy as his apprentice.  Giving him the name Starkiller, Vader began a brutal training program, leaving the adult Starkiller with many scars from close calls with a lightsaber.  Many times during the training, Galen felt he was close to death, and believed that this strengthened him in the Dark Side.

After many years and many difficult trials, Starkiller was deemed ready to begin his true mission.  He began hunting down Jedi on orders from Vader.  First was General Rahm Kota, who escaped the Purge due to using his own militia, rather than the clone troops.  His group was attacking a base constructing TIE Fighters, and after tearing through a great deal of militia (and flinging unfinished TIEs around with the Force) he found Kota.  The two had a fierce duel, with Starkiller winning in the end...or so he thought.  Before the end, Kota peered into Starkiller's future, and to his shock, all he saw was himself.  This shock is what allowed Starkiller to take his eye and knock him out of a hole in the floor.  Next was Kazdan Paratus, a Jedi that had taken up residence in a junk heap on Raxus Prime.  The droids he encountered there were powered by the Force, a fact with seemed to shock him slightly.  In the end, he destroyed Kazdan Paratus and returned to Vader with his lightsaber.  Next came Shaak Ti, the only surviving member of the Jedi Council (so Vader believed at the time).  He went through her as well.  It was after this that his first "death" occurred.

When he returned from the mission to kill Shaak Ti, Vader told him that it was time to destroy the Emporer, and that he should report to the Executor.  Strangely, when Galen arrived, Vader claimed he did not give such an order.  Galen was allowed his confusion for only a moment, before Vader brutally impaled him on his lightsaber.  PROXY, in the form of the Emporer, commanded Vader to finish his apprentice or he would kill them both.  Vader responded without hesitation, slamming Galen into the walls twice before flinging him through the view port.

Galen awakened six months later aboard Vader's personal science vessel, the Empirical.  Despite the initial rage directed towards his master, he calmed considerably when it was explained that Vader had a new mission for him.  He was to distract the spies on Vader by giving them something else to focus on...like a rebellion.  This was the beginning of the Starkiller the Sith's undoing, and the start of the reemergence of Galen Marek, Jedi.  Taking his pilot Juno Eclipse and his friend PROXY, he began the search for Rahm Kota.  Finding him in a bar on Cloud City, Galen learned that Kota was blind, and (supposedly) no longer had a connection to the Force.  He also learned that Kota had a contact in the Senate that could help their fledgling rebellion, but before much could be discussed, the Emporer's guards arrived and both were forced to flee.  It was revealed that Kota's contact had a daughter that needed rescuing, and that Kota had refused.  If Galen did the job, perhaps the senator would listen.  This job required a return to Kashyyk...

...where Galen Marek met Princess Leia Organa of Alderaan, the daughter of Kota's contact, Bail Organa.  True to her nature, Leia refused to leave until the skyhook, a massive construct used by the Empire to take Wookie slaves off Kashyyk, was destroyed.  Battling alongside the Wookies, Galen was able to destroy the skyhook.  Perhaps things would have been different if that was all that happened on Kashyyk.  Perhaps if Galen hadn't found that one lonely hut with the strangely familiar symbol on it, perhaps if he hadn't gone in and witnessed the ghostly manifestation of his father, the Starkiller persona would have won out in the end.

Perhaps.

Of course, things didn't get easier just because Galen rescued Leia.  Frustrated by Kota's refusal to help, Bail went to Felucia looking for Shaak Ti, unaware that she was dead.  Galen, Juno, Kota, and PROXY traveled to Felucia, where they discovered that the planet had become corrupted by the Dark Side.  According to Maris Brood, who was now a sith, the entire planet changed when Shaak Ti was killed.  Galen was forced to fight Maris Brood's pet bull rancor, and after that engaged Maris in a duel.  He fairly easily outclassed her, and the duel ended with Maris Brood begging for her life.  Despite Bail's protests, and with perhaps a little hesitation, he let Maris go.

During the return trip to Raxus Prime, Galen modified his lightsaber, changing it's hue to aqua and truly claiming it as his own, rather than just being Kota's old saber.  The fledgling rebellion still had much to prove.  Seeking a target that would truly resonate, Galen consulted with Vader and determined that there was a shipyard building Star Destroyers that would make a fine first target for the organized rebellion.  Unfortunately Juno caught him, and she was not very happy with it.  She planted the seeds of choice in Galen's mind, seeds that would eventually bear fruit.

At the shipyard, Galen fought through a great deal of armed resistance, and successfully reprogramed the ore cannon there to fire at the shipyard itself.  The downside of this plan?  Damaged Star Destroyers tend to get grabbed by the gravity generated by planets they're near.  Oops!  Kota instructed Galen to use the Force to crash it into the ore cannon, and he did it.  Miraculously surviving the tremendous crash, Galen returned to his ship, only to discover that PROXY had been corrupted by the living computer core of Raxus Prime.  Pursuing his friend into the shipyard, he battled many droids, the Core itself, and PROXY (in the guise of a heavily tattooed Zabrak that Obi-Wan Kenobi would have recognized...) and succeeded in recovering PROXY.  PROXY insisted Galen leave him, but Galen refused to leave his friend and brought him back to the ship.

From there, they went to Cloud City to contact Garm Bel Iblis, only to discover that he'd been kidnapped by a criminal.  Successfully rescuing Garm, the rebellion was beginning to take a shape resembling the Rebel Alliance of later years.  Mon Mothma also joined, and so the initial rebellion was formed.  They all met on Corellia to sign the treaty...and disaster struck.

Vader and the empire struck!  As it turns out, Vader had no intention of destroying the Emporer...at least, not with Galen.  Preparing to destroy Galen, Vader found himself instead engaged by PROXY.  It didn't last long.  Vader then revealed to all those gathered that this whole thing was a ploy to gather the empire's enemies into one place for easy retrieval.  He also revealed Galen's status as his apprentice.  The senators were struck hard by this blow, their morale nearly shattered.  It seemed that perhaps, the rebellion might die before it ever officially began.  Some hope remained, however.  Galen, using PROXY's distraction to his advantage, voluntarily toppled off of a cliff.

Juno found Galen, having miraculously survived the fall, and brought him back to the ship.  The Starkiller persona was entirely gone now, and together the group set off to rescue the senators.  They traveled to the Death Star, where Galen shared a passionate kiss with Juno, both of them aware that Galen was probably not going to be coming back from this one.  Battling through perhaps the largest force he'd dealt with so far, Galen rescued the senators and even defeated Vader in a duel.  Tempted by the Emporer to kill the man that had murdered his father, Galen's future as a Jedi hung more precariously than it had since his first "death".  Kota, sensing this, revealed that he still possessed a connection to the Force by taking Palpatine's saber and attacking him with it.  He didn't even make it all the way to the Emporer.  Seems the huge bolts of lightning he was throwing were quite painful, imagine that!

Galen made the right choice in the end.  He attacked Palpatine, actually besting him in use of the Force.  In that moment he could have killed him, could have ended the empire right there...but he would have become just as bad, if not worse, for it.  The Emporer had foreseen such a thing, and attacked Kota with Force Lightning once again.  Galen made the ultimate sacrifice, stepping in front of the stream of lightning and catching it, much like Yoda had before him.  Telling Kota to protect the senators, and commanding them to go, he began closing the distance between himself and Palpatine.  Unable to stop him, Palpatine could only watch as he forced their hands together, causing a massive backfeed and explosion.  This explosion gave the senators time to escape, but at the cost of killing Galen.  Neither Vader nor the Emporer died that day, but the rebellion lived to destroy them in the future.

In honor of Galen Marek and all he did for the rebellion, Bail and Leia Organa revealed that the Marek family crest would be used as the symbol of their new Rebel Alliance.

Galen arrives in UTR after his death in the incomplete Death Star.