Flash was an Alpha-Class Advanced Recon Commando who was forgotten in stasis when the Kaminoans released the first of the ARC Troopers. So he had a full extra year to think and develop. So when he was released he was the best of the best and was instantly promoted,Although he got to keep his blue armor.
About this creation
Flash ranks higher than even Alpha-17 himself! But flash believes that he and his brothers are equals so he comes to the front line to fight like any other clone every chance he gets.