When Order 66 started a large scale of the inhibitor chips somehow malfunctioned in the clones. The clones who's chips malfunctioned fought back against their brothers, before stealing supplies, blasters, food, and water. They also rescued all the young cadets off Kamino. They also stole the some equipment that the Kaminoans used to make more clones. They stole large ships and vehicles, then proceeded to to leave Kamino to lay low. But before all this happened a clone commander named Viper had his chip removed in secret by a young female Jedi who later fled and was never seen again but left some information about Order 66, and how to destroy the chips in all of his brothers. Viper managed to destroy a large number of of inhibitor chips leading up to saving 10,000,000 of his brothers. They became an army led by Viper and his squad. Deadbeat, Crosspatch, and Shocker and with all their brothers they fought back against the Empire
That's when the Batch Bach, Captain Rex and everyone else out in the Galaxy hears about this and people started to call them
THE ROUGE LEGION