Null-class ARC Troopers
this was the so-called "black operatives" group of the Grand Army of the Republic, rumored to have been trained as intelligence operatives, but deemed too dangerous to deploy by the Kaminoan cloners who created them. According to rumors, the Null ARC Troopers were trained by Kal Skirata, since he essentially disappeared after training the first squads of ARC troopers and clone commandos. The development of the Null-class ARC Trooper was begun by taking the pure genome of Jango Fett and altering it with specific changes or deletions. Only twelve of these Null ARCs were ever produced, and only six managed to survive the gestation period. The survivors proved to be among the most effective black-ops units in the entire galaxy, but were considered unpredictable, and were feared because of their unswerving loyalty to Skirata.