The operation known as the Mission to Kashyyyk involved Starkiller undertaking a rescue of Princess Leia Organa. This was part of his broader objective: the formation of an army intended to stand against the might of the Galactic Empire.
After Rahm Kota had been saved and brought aboard the Rogue Shadow, he made it clear to Marek that attempting to overthrow the Galactic Empire was an exercise in futility. However, he mentioned having a contact within the Imperial Senate who might be swayed by Marek's skill with a lightsaber. To secure this contact's assistance, a task was required: traveling to the world of Kashyyyk to recover an item of great personal value to the senator. Success in this endeavor, it was suggested, could potentially lead to the senator's support in establishing a rebellion aimed at toppling Emperor Palpatine's galactic dominion.
Having landed on Kashyyyk, Marek ventured forth from the Rogue Shadow on his own. He navigated through territory under Imperial control with the goal of locating the individual he was tasked with rescuing.
His assignment included rendering the base's communications tower inoperable, along with deactivating the containment shield. As Marek progressed further into the base's interior, he encountered a member of the Emperor's Royal Guard stationed at the quarters of Captain Ozzik Sturn. Sturn had been reassigned to Kashyyyk due to his extracurricular interests in hunting exotic creatures. Marek battled his way into the compound with the aim of liberating Leia Organa from Imperial custody, hoping to secure the backing of her father, Senator Bail Organa.
The Princess initially mistook the intruder for an assassin dispatched by the Emperor. However, he convinced her of his true purpose: to rescue her. It was at this point that Marek learned that the Princess's father was the source of Rahm Kota's intelligence regarding Imperial targets. Princess Leia agreed to leave, but only if Marek would destroy the local Skyhook. The Empire was constructing this structure on Kashyyyk to facilitate the transportation of Wookiees off-world for use as slave labor. When Marek pointed out that the Empire could simply rebuild it, Organa conceded that this was likely, but it would at least provide the Wookiees with an opportunity to seek refuge. She then inquired about the shuttle's location, noting that the pilot was dead. Galen confirmed its presence but noted the pilot's demise, prompting the Princess to ask why he thought she needed one.
After contacting Juno, PROXY informed Galen that destroying the tractor beam would achieve the desired outcome, although it would result in a powerful explosive reaction. Marek fought against Imperial forces, attempting to reconfigure the tractor beam emitters located at the base of the platform.
During his efforts to sabotage the equipment supporting the skyhook, Marek clashed with Ozzik Sturn, who commanded the Imperial garrison on the planet. Sturn, piloting a modified AT-ST, engaged Marek, and he and his troopers attempted to eliminate the Jedi. However, they were defeated, and the tractor beam was disabled, leading to the skyhook's destruction. This action delayed the Empire's efforts to exploit the Wookiees as a source of slave labor, granting them valuable time to organize resistance against Imperial rule. However, according to Galen, the Wookiees who remained on Kashyyyk expected it to be rebuilt.
The Kashyyyk mission is presented in Act II of the Star Wars: The Force Unleashed video game under the title "Imperial Kashyyyk". The Wookiee characters featured in this level are intentionally designed to differ from the Wookiee warriors and Berserkers that appear earlier in the game. The change reflects the story; the Wookiees had been enslaved by the Empire, and their appearance is intended to convey their ragged condition.
The sequence of events varies across different versions and media. In the video game, Starkiller lands near Kento Marek's hut and encounters the Force ghost of his father, before proceeding with his mission. In the comic adaptation, he experiences a vision of his father's death and capture by Vader before encountering his father's ghost, after which he continues his mission to find Leia. The comic omits any mention of Sturn, the Wookiees, or the skyhook.
In both the Nintendo DS version and the novelization, he meets Leia prior to discovering his father's hut. In the DS version, he defeats Ozzik Sturn, locates the hut, and engages in a battle with a Light Side version of himself before seeing his father's ghost. He then proceeds to destroy the skyhook. In the novelization, he experiences a vision of Vader's battle on the planet before Vader kills Kento and taking Starkiller with him. Then he undergoes a transformation into a Sith Assassin and fights a Jedi figure, whom he defeats, before meeting his father's ghost. Subsequently, he continues his mission.