Anti-troopers represented the final line of clone troopers, crafted exclusively from the genetic blueprint of Jango Fett. Their armament and weaponry were relics from the era of the Grand Army of the Republic. Consequently, they were outfitted with Phase I clone trooper armor and the standard DC-15A blaster rifle. Trained as specialized clone jet troopers, these anti-troopers made use of jetpacks, which provided them with an elevated position and swift movement during engagements, complementing their clone trooper armor.
This fresh wave of Fett clones was activated by a dissident group of Clone Masters, who aimed to free their home planet of Kamino from the oppressive grip of the Galactic Empire. Thus, none of these anti-troopers harbored any loyalty to Emperor Palpatine or his New Order; their allegiance was solely to their Kaminoan creators. Upon discovering the existence of this renegade clone army around 12 BBY, the Empire dispatched a division of stormtroopers belonging to the renowned 501st Legion, tasking them with the elimination of the anti-troopers and the restoration of Imperial control over Kamino.
The 501st, comprised of clone soldiers who once fought for the Galactic Republic, launched an assault on Tipoca City, where they faced resistance from the anti-troopers and a supporting contingent of Rail-class Advanced Recon Commandos. Leading the legion's combat operations was Boba Fett, a renowned bounty hunter and an unaltered clone, hired by the Empire to spearhead the attack on Kamino due to his established connection with the planet and its primary urban center. In the end, the facility fell to Imperial forces as the veteran Clone War clones decimated the anti-troopers and Rail-class Advanced Recon Commandos, along with their Kaminoan overseers who attempted to flee during Tipoca City's downfall.
The creation of these anti-Imperial clone troopers led to a restructuring of the Imperial Military. Although the Empire continued to utilize Fett clones for several years after Palpatine's rise to power, the Emperor ultimately decided that an army of clones derived from a singular genetic source was too vulnerable to manipulation. Consequently, subsequent clone stormtroopers were cultivated from a variety of genetic templates. Eventually, the Stormtrooper Corps broadened its recruitment to include naturally born Humans who enlisted as recruits or were conscripted. While the military became increasingly diverse, only the 501st—the personal legion of the Sith Lord Darth Vader—was permitted to maintain its ranks exclusively with Fett clones.
During the concluding year of the Clone Wars, a disagreement arose between Prime Minister Lama Su of Kamino and Supreme Chancellor Palpatine of the Galactic Republic. Kamino had been the main provider of clone troopers for the Republic army until the Chancellor authorized the construction of new cloning facilities on Coruscant and Centax-2. Utilizing Spaarti cloning technology, these new generations of Fett clones could be fully developed within a single year, a stark contrast to the ten years required by Kaminoan methods. Instead of entrusting the oversight of these new cloning centers to Kaminoan scientists, the Chancellor placed the Spaarti-grown clones under the care of Arkanian Microtechnologies. Unbeknownst to Chancellor Palpatine, however, Lama Su did not relinquish all of the clone troopers to the Republic.
As the Clone Wars drew to a close in 19 BBY, the Republic underwent a transformation into the Galactic Empire, the Jedi Order suffered a devastating betrayal and near-total annihilation, and Chancellor Palpatine proclaimed himself emperor of the galaxy. The Republic clone troopers, programmed with unwavering loyalty to the Chancellor, were rebranded as Imperial stormtroopers. Shortly thereafter, Kamino found itself under Imperial military occupation, with the Kaminoans' own creations seizing control of the cloning facilities to ensure the continued production of clone stormtroopers for the Empire. Disenchanted with Palpatine and resentful of the Imperial presence on their world, a rebellious faction of Kaminoan Clone Masters initiated a secret project to create a new clone army—one that would be loyal to Kamino rather than the Empire.
Through Kamino's advanced cloning technology, the Anti-Imperial clone troopers—also known as Anti-troopers—were engineered over nearly a decade within the Tipoca City Cloning Facility. Like the original clone troopers who served in the Clone Wars, the entire Anti-trooper army was based on the genetic blueprint of the deceased bounty hunter Jango Fett. The Kaminoan Clone Masters also secretly commissioned a special forces unit of Rail-class ARC troopers to complement the Anti-troopers and bolster the strength of Kamino's growing rebel Fett clone army.
To ensure the Anti-troopers' superiority over their older clone brethren, they were all trained as jet troopers and equipped with limited flight jetpacks in addition to their Phase I clone trooper armor. They were also trained as both expert snipers and infantry soldiers, and were thus equipped with DC-15x sniper rifles and DC-15A blaster rifles, weapons commonly used by the original clone troopers during the Clone Wars.
After nearly a decade of Imperial occupation, Kamino's new clone army had completed its development and was prepared to launch its "Clone Rebellion" to liberate Kamino from the Galactic Empire. Their unwavering allegiance belonged to their Kaminoan creators, making them fully prepared to fight the Empire and eliminate their Imperial counterparts. When the Empire discovered the Kaminoans' plot in 12 BBY, the 501st Legion was ordered to restore Imperial control over Kamino by annihilating its rebel clone army. Leading the 501st was the bounty hunter Boba Fett, the sole unaltered clone of Jango Fett.
The Kamino uprising began with Boba Fett leading the stormtroopers of the 501st Legion in an attempt to infiltrate Tipoca City. Their primary objective was to secure a canister containing Jango Fett's genetic material, ensuring its protection during the battle. The Anti-troopers immediately engaged their Imperial counterparts in combat, and despite their willingness to fight to the death, they ultimately failed to prevent Fett and the 501st from entering the cloning facility.
With Jango Fett's DNA secured, Boba Fett promptly returned to a secure platform where an Imperial shuttle transported the canister off-planet, ensuring the Empire's continued ability to produce more Fett clones. Meanwhile, the Anti-troopers continued to engage the 501st Legion on the city's numerous platforms. However, unable to gain an advantage or shift the battle's momentum, they steadily lost ground to the relentless advance of the 501st stormtroopers.
After securing more ground on the platforms, the 501st proceeded to infiltrate the inner workings of the cloning facility with the objective of destroying the life-support system consoles that kept undeveloped rebel clones alive, thus preventing the Kaminoan rebels from cloning more Anti-troopers. Along the way, however, the Rail-class ARC troopers emerged and began attacking the 501st. But despite their best efforts, the 501st was still able to enter the city and destroy the life-support systems and abort the developing rebel clones.
With the battle lost and their homeworld on the verge of falling completely under the Empire's control, the Kaminoan Clone Masters attempted to retreat by utilizing a pair of LAAT gunships to evacuate Tipoca City. The last of the Rail-class ARC troopers joined with the remaining Anti-troopers outside of the city. Together, they made their last stand on Tipoca City's platforms in a fight to death in order to buy their creators enough time to escape. Their sacrifice was ultimately in vain, however, and the 501st was able to destroy the gunships before they took off, and thus they killed the Kaminoans who created the rebel clone army. The end of the Clone Rebellion saw every last Anti-trooper and Rail-class ARC trooper massacred down to the last clone. Tipoca City, every other Kaminoan cloning facility, and all of Kamino and its people became fully subjugated to the Galactic Empire.
The Anti-troopers' failure had far-reaching consequences, not only for Kamino but also, ironically, for the Imperial clones of Jango Fett. With Kamino under complete Imperial control, the Kaminoan race was compelled to continue its service to the Empire by producing countless clone stormtroopers. In addition to the Kaminoan scientists, Imperial Human scientists were brought in to oversee the growth of Imperial clone soldiers as well.
Although the 501st Legion reaffirmed its loyalty to the Empire by eliminating their rebel clone brothers to suppress the Kaminoan rebellion, Emperor Palpatine ultimately decided that the ranks of the Stormtrooper Corps could no longer be exclusively filled by Jango Fett's progeny. Even though enlisted personnel had long since become part of the overall Imperial Military, including the Army and Navy, the Fett clones took pride in the fact that they alone served as the Emperor's stormtroopers, just as they had done so for the Republic as clone troopers. The thought of serving alongside clones that were based on different templates, or even enlisted stormtroopers, was appalling to the proud clones of Jango Fett.
Nevertheless, their programmed loyalty to the Emperor prevented them from displaying their dismay in any way, thus forcing them to watch as the Stormtrooper Corps became increasingly diverse. Ultimately, Fett's clones were reduced to the status of a small minority and became lost in a sea of non-Fett clones and enlisted soldiers. While the 501st Legion remained pure of outsiders for a time, none of Jango Fett's clones ever became used to the idea of fighting alongside the soldiers they mockingly dubbed as "the new guys."
Roughly a decade later, the resentment only grew worse, especially for the few remaining veterans of the Clone Wars. By the year 2 BBY, Commander Cody was in charge of the Imperial garrison of Kamino, most of which was composed of enlisted troopers. Having watched the obvious decline in the Imperial Army's operational effectiveness ever since the Empire increased its pool of stormtrooper recruits, Cody developed an intense hatred for all stormtroopers that were not clones of Jango Fett. He regarded them as expendable idiots with no sense of themselves or their surroundings, and would have happily traded them all for just one real clone trooper.
Although the Anti troopers wear Phase I clone trooper armor in Star Wars: Battlefront II, two troopers seated in the turrets of the LAAT gunships on the "Kamino Uprising" level are wearing Phase II clone trooper armor. After the battle's conclusion, the retired clone trooper stated that Boba Fett left Kamino, mentioning that he was going to Tatooine to track down a smuggler, obviously referring to Han Solo.