Captain Rex

The most well-known and decorated clone trooper captain from the Clone Wars during the days of the Galactic Republic, Rex led the famed 501st Legion, the clone force which arguably saw the most action during the course of the war. He commanded 501st campaigns on Christophsis, Teth, Mon Cala, Umbara, Ringo Vinda, Scipio, and many other planets. Additionally, Rex went on several individual campaigns with his Jedi General Anakin Skywalker, such as the infiltration of Zygerria and the reinforcement of Onderon. After his brother-in-arms, ARC trooper Fives, died, Rex decided to investigate and remove the control chip embedded in his brain, fearing it would cause catastrophic consequences. Rex's final mission was with Padawan Ahsoka Tano to the Siege of Mandalore, where the fateful Order 66 command was issued. Rex, however, had removed his chip, and after faking his and Ahsoka's deaths, the two of them escaped. Many years later, a rebel cell found Rex and two other clone troopers, Gregor and Wolffe, living in a walker on Seelos. Rex joined the rebellion, and assisted the crew of the Ghost on several battles such as the liberation of Lothal, later commanding a part of the ground team on Endor.

Rex, despite being strictly by-the-book at first, ultimately became more adaptable and creative, heavily influenced by his Jedi General Anakin Skywalker, as well as his fellow soldier and friend Fives. Due to Fives' death, Rex removed his control chip, allowing him to avoid executing Order 66.