Battle on Death Star I

A final confrontation between the Sith Lord Darth Vader and his former apprentice, Galen Marek, occurred on the first Death Star in 2 BBY at the start of the Galactic Civil War between the Galactic Empire and the Alliance to Restore the Republic. Following the capture of the rebellion founders on Corellia, the apprentice was betrayed and left for dead by his master. In retaliation, Marek re-embraced his Jedi heritage and pursued the Dark Lord of the Sith to the Empire's incomplete battle station, intending to save his new-found allies and — by extension — the Rebel Alliance itself.

Breaching the inner defenses of the Death Star, the apprentice killed numerous stormtroopers and other Imperial soldiers before reaching the Imperial throne room where he confronted Darth Vader in single combat. In a contest of both skill and power, Vader was ultimately bested and found himself at the mercy of his former apprentice. Vader's own master, Darth Sidious—better known to the galaxy as Emperor Palpatine—not only praised Marek's victory, but also attempted to hypnotically compel the apprentice into killing his grievously damaged and defenseless master. In Marek, Sidious saw the opportunity to replace his hobbled enforcer with a younger and more powerful disciple. Jedi General Rahm Kota, one of the prisoners captured on Corellia, sensed the Emperor's intentions, however, and tried to prevent the apprentice from falling to the allure of the dark side once more. The distraction worked to break Sidious's hold on Marek, who then confronted the Dark Lord in defense of his friends. Refusing to allow the Jedi to claim the apprentice's potential for their own gain, an enraged Sidious tried to kill Kota with Sith lightning. Marek protected his mentor by absorbing the energy into his own body, but at the cost of his own life. In order to prevent a squad of stormtroopers from killing the Rebels, Marek unleashed the power of the Force from within himself, and then died as a result of the explosion.

The Rebel leadership — senators Bail Prestor Organa, Garm Bel Iblis, and Mon Mothma — were evacuated from the Death Star in the apprentice's starship, Rogue Shadow, piloted by former Captain Juno Eclipse of the Imperial Navy. Together with Kota, the group rendezvoused on Galen Marek's home planet, the Wookiee world of Kashyyyk, where they formally declared the birth of the Rebel Alliance. In honor of their fallen leader's sacrifice, the new organization adopted Marek's family crest as their emblem; a symbol of hope for those who yearned for the restoration of the Galactic Republic.

Darth Sidious, far from pleased with the untimely demise of Darth Vader's apprentice, was even more irate upon the realization that the Empire would have to actually fight a civil war against an insurrection that was secretly masterminded by the Sith Order — namely Sidious and Vader through Marek as their proxy. Forced to tolerate Vader's existence for a while longer, the Emperor tasked Darth Vader with the complete destruction of the newly formed Alliance, fearing that the Rebellion could destroy the New Order that the Sith built after centuries of plotting the downfall of the Jedi Order and their Republic.

Text and facts from the “Battle on Death Star I” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.