During the Onderon insurgency, a specific mission targeting Onderon took place not long after the Galactic Empire was established. In this operation, Clone Commander CT-9904, known as "Crosshair," led a squad of newly conscripted recruits in an assault. Their target was a contingent of Saw Gerrera's rebels stationed on Onderon, an engagement that concluded with the complete elimination of the rebel forces.
The year 19 BBY marked the conclusion of the Clone Wars, a conflict between the Galactic Republic and the Confederacy of Independent Systems. The war ended abruptly when Darth Sidious, the Dark Lord of the Sith who orchestrated the entire conflict, issued Order 66. This command compelled the clone troopers of the Grand Army of the Republic to betray and execute their Jedi commanding officers. The order was facilitated by secret behavioral modification biochips implanted in the clones by the Kaminoan cloners. Following the shutdown of the Separatist Droid Army by Sidious' Sith apprentice Darth Vader, Sidious, publicly known as the Republic's Supreme Chancellor Sheev Palpatine, declared the war over, falsely claiming a "Jedi rebellion" had been crushed. He then proceeded to reorganize the Republic into the Galactic Empire.
While the vast majority of clones were brainwashed into unwavering obedience to Sidious and his Empire, there were a few exceptions. Notably, most members of Clone Force 99, an unconventional clone commando unit primarily composed of genetically defective clones whose mutations shielded them from the effects of the chips, were among these exceptions. During a battle on Kaller when Order 66 was issued, the squad witnessed the execution of Jedi General Depa Billaba by her own soldiers, followed by the escape of her Padawan Caleb Dume. Clone Sergeant Hunter pursued Dume to assist him, accompanied by the team's sniper, CT-9904 "Crosshair." Crosshair was the only member of the "Bad Batch" affected by Order 66 and attacked Dume, who briefly incapacitated him before fleeing. Hunter falsely claimed to Crosshair that Dume had died after falling into a ravine, but Crosshair suspected the truth.
Upon the Bad Batch's return to Kamino, Crosshair secretly reported Dume's survival. Shortly after the Empire's declaration, Admiral and Governor Wilhuff Tarkin visited Kamino to assess the clones and inform the Kaminoans of the Empire's intention to cease clone purchases. As part of his evaluation, Tarkin subjected Clone Force 99 to a combat test. While impressed by their skills and tactics, he was concerned about their disobedience, particularly Crosshair's report, and questioned their compliance with Order 66. Tarkin decided to test their loyalty by assigning them a mission on Onderon to eliminate a group of former Republic fighters led by Saw Gerrera, who had led rebels against a Separatist-backed king during the planet's civil war. Gerrera, who continued to fight for the Republic after the civil war, refused to serve the Empire, forcing him, his fighters, and civilian refugees into hiding in Onderon's jungle.
Believing they were targeting Separatist insurgents, the Bad Batch was surprised by the true nature of their targets. All members, except the brainwashed Crosshair, refused to carry out the mission. After speaking with Gerrera, Hunter allowed him and his people to leave peacefully. They then discovered that Tarkin had been spying on them using a probe droid. Most of the Batch decided to desert the Empire, but Hunter resolved to return to Kamino to rescue Omega, a young enhanced clone they had recently met who tried to warn him about the mission. Upon returning to Tipoca City, the Bad Batch was arrested and imprisoned, where they found Omega, who had been detained by the Coruscant Guard after they found her in the squad's barracks.
Tarkin learned from the probe droid's report that Crosshair had expressed loyalty to the Empire on Onderon and had him taken away by Imperial shock troopers. A medical examination by Doctor Nala Se revealed that the sniper's inhibitor chip was active, but less so than in standard clones. At Tarkin's direction, Crosshair underwent a procedure to amplify the chip's effects, ensuring his complete loyalty to the Empire. The remaining Bad Batch and Omega escaped from their cell and located their starship and equipment, hoping to rescue Crosshair. However, the mind-controlled sniper confronted them in a hangar with a squad of shock troopers. After a firefight, the Bad Batch and Omega fled Kamino in the Marauder.
As part of Project War-Mantle, the Empire's initiative to recruit natural-born soldiers, Vice Admiral Edmon Rampart selected four skilled individuals from across the galaxy to form the initial Elite Squad Troopers. Under Tarkin's guidance, the new unit was placed under Crosshair's command, who was promoted to Clone Commander, as part of their training. Tarkin dispatched the unit to Onderon to complete the mission Clone Force 99 had failed to accomplish: the elimination of Gerrera. They traveled in a Nu-class shuttle. ES-01, one of the recruits, harbored disdain for Crosshair due to his clone status and openly aspired to take command of the unit.
The squad arrived on Onderon near a rebel camp where several of Gerrera's fighters were preparing to evacuate, intending to transport refugees to a rendezvous point in an LAAT/le patrol gunship. Gerrera himself was absent. The rebel commander was alerted to the approaching enemy when sensors were triggered in Sector 2A. Crosshair initiated the attack by shooting several rebel fighters from concealed positions in the trees before signaling his troops to advance.
The rebels returned fire while moving the refugees into the gunship, but struggled to locate the enemy as they continued to suffer losses. The Imperial troopers employed both blasters and a flamethrower to overwhelm the rebels. A missile launcher was inadvertently fired after its wielder was killed, sending a rocket into nearby ruins. The rebel commander attempted to seize control of the gunship after the survivors boarded, but he was shot through the viewport by an Elite Squad Trooper who had flanked the camp and positioned himself in a tree.
The refugees and a single surviving rebel were forced out of the gunship. As the rebel surrendered, Crosshair interrogated her about Gerrera's location. She refused to provide information, even under duress, and was subsequently executed. Crosshair then prepared to execute the civilians, shocking the recruits. ES-01 vehemently objected, stating that they had not enlisted to become an execution squad. Attempting to assert authority, he declared that none of the recruits would follow the order and instructed them to ignore Crosshair and take the refugees into custody. Crosshair confronted him, emphasizing that he was in command precisely because he would follow orders, before executing ES-01 for insubordination. He then ordered the remaining recruits to carry out the execution, which they reluctantly did.
The remaining members of Elite Squad returned to Kamino, where Crosshair reported that Gerrera was not present at the camp, but all other targets had been eliminated. Tarkin acknowledged the loss of a soldier, but Rampart argued that casualties were inevitable in war. Pleased with the project's progress and the success of Crosshair's team compared to the Bad Batch's failure, Tarkin placed the project under Rampart's full supervision. However, he cautioned that the Empire was not yet ready to abandon the clone army until sufficient recruits were available to allow the Emperor to retire the Old Republic soldiers.
The barracks in Tipoca City previously occupied by the Bad Batch were reassigned to Elite Squad. Upon arrival, Crosshair reclaimed his former bunk, but was left thoughtful by the remaining signs of its previous occupants.
Kaminoan Prime Minister Lama Su and Nala Se were deeply concerned about the Empire's recruitment plans. Seeking to maintain the Empire's business, Lama Su authorized Nala Se to continue working on an experiment to create a superior clone. However, the clones from whom they needed genetic samples would not willingly return to Kamino. Considering them Kaminoan property, Lama Su believed that only one of the clones was necessary for the project's success.