Clone Troopers are loyal and obedient soldiers first introduced in Star Wars The Clone Wars. They were commissioned by a fallen Jedi Master and created to form the army for the Galactic Republic Army.
They had a command chip in their brains that would activated after Order 66, a command proclaiming Jedi enemies of the state and to turn on their Jedi commanders. However, the Clones could not resist, except for General Rex, who had his chip removed.
The Clone Troopers were retired by Emperor Palpatine after their usefulness was over and went to live in corners of the Galaxy, all ashamed with how they were forced to betray their Jedi Generals.