Jai'galaar, frequently called Jag, and known as CT-55/11-9009, was a clone trooper captain who fought for the Galactic Republic throughout the Clone Wars. Originally a clone pilot who adopted the Mando'a name Jai'galaar, Jag started as a Clone Commander during the First Battle of Geonosis, but following the Retreat at Katraasii, he was reduced in rank to captain. Subsequently, Jedi General Plo Koon selected the captain to be a test pilot for the new ARC-170 starfighters. During the battle above Cato Neimoidia, Jag acted as Koon's wingman and killed the Jedi once Order 66 was given by Supreme Chancellor Palpatine.
CT-55/11-9009, who went by Jai'galaar, or simply Jag, was one of the numerous clones created from the Mandalorian bounty hunter Jango Fett.
At the time of the First Battle of Geonosis, Jag, then holding the rank of Commander, was in command of the 127th Gunship Wing. He belonged to the renowned CT-5 batch of clone troopers, and was a skilled, somewhat aggressive pilot, although his true calling was leadership, not flying.
However, Jag later suffered disgrace and demotion following the disastrous Retreat at Katraasii. Fortunately for Jag, Jedi General Plo Koon chose him to be a test pilot for the new ARC-170 starfighters.
Upon the issuing of Order 66 by Supreme Chancellor Palpatine, Captain Jag, flying his ARC-170 fighter, together with his ARC-170 starfighter squadron, destroyed General Koon's Delta-7 Aethersprite-class starfighter above Cato Neimoidia during the battle that took place there, despite any personal feelings he may have had for the Jedi.
Jag made the decision to use an unidentified script to show information on the cockpit display of his ARC-170 starfighter. This script was used to display information just before he shot down Plo Koon's Delta-7 Aethersprite-class light interceptor.