Background: CT-5555 (short for CT-27-5555), and later referred to as ARC-5555, or just “Fives”, was an Advanced Recon Commando who served in the Grand Army of the Republic during the Clone Wars. Due to his clone designation, he referred to himself as “Fives.” Originally a clone cadet during the early phase of the pan-galactic conflict between the Galactic Republic and Confederacy of Independent Systems, Fives completed his training on Kamino and attained the rank of trooper alongside his teammates in Domino Squad. As a newly-trained soldier, he was stationed in a Republic outpost on the Rishi moon at the time of a Separatist attack on the installation. As one of only two survivors, Fives was recruited into the 501st Legion. Following the successful defense of Kamino, he joined the ranks of the elite Advanced Recon Commandos along with CT-1409 “Echo,” the only other survivor of the attack on Rishi Station.
Following the capture of Jedi General Even Piell, Fives was deployed with a team of Jedi and clones to Lola Sayu in order to rescue the imprisoned General from a facility known as the Citadel. Though the team sustained multiple casualties over the course of the mission, resulting in the death of Piell and the loss of Echo, who was presumed dead, Fives was among the survivors rescued by Jedi General Plo Koon. Later in the war, Fives served with the 501st during the Battle of Umbara. During the campaign, he played a key role in both the capture of the Umbaran airbase and the destruction of the Separatist supply ship. However, the clones ultimately discovered that their general, the Besalisk Jedi Master Pong Krell, had betrayed the Republic, deceiving his own clone troopers into fighting each other. As a result, Fives participated in their efforts to capture the fallen Jedi.
While attempting to take Ringo Vinda from the Separatists, Fives witnessed the death of Tiplar, a Jedi General executed mid-battle by CT-5385 “Tup.” A chain of events was set in motion by the preemptive execution of Clone Protocol 66, leading Fives to discover a conspiracy involving inhibitor chips, a plot to destroy the Jedi Order, and—to an extent—Supreme Chancellor Sheev Palpatine’s connection to it. After being accused by Palpatine as a failed assassin, Fives sought to warn Jedi General Anakin Skywalker and Clone Captain CT-7567 “Rex” but was confronted by Clone Commander CC-1010 “Fox” and a contingent of Coruscant Guard shock troopers. When a desperate Fives, believing that no one would listen to the information he had learned about the inhibitor chips, drew his weapon on Fox, he was killed by him, dying in Rex’s arms.
Although Fives was killed before he could expose the conspiracy behind the inhibitor chips, his actions impacted the execution of Order 66. At least two clones—CC-3636 “Wolffe,” and CC-5576-39 “Gregor”—removed their chips prior to the activation of Order 66. CT-6116 “Kix” conducted his own investigation which led him to discover Palpatine’s conspiracy and forced Dooku to abduct and freeze him within cryo-cycle stasis to prevent the information from being leaked, thus removing him from any further involvement within The Clone Wars and Order 66. When members of the 501st executed Order 66 against Ahsoka Tano, she used Fives’ knowledge of the conspiracy to save Rex and remove his inhibitor chip. As such, they did not turn against the Jedi unlike the rest of the clone army that went on to serve the Galactic Empire.