This mod is based on books by Karen Travis. It follows the story of Delta 38 "Boss" and Delta Squad throught the clone wars. It is an expansion to default story with weapons , characters and missions from books , expanded universe and movies.
Rail Class ARC Commandos were elite ARC trooper units created by Kaminoans to aid the regular Anti Troopers during the planned uprising against the empire.
Empire found out their plans and sent 501st and Bobba Fett to shut down clone factories and steal the genetic template. 501st succeeded, bringing the end to the planned uprising before it could even begin.
Looks great!