CC-3993, nicknamed Nix, was a clone officer holding the rank of Senior Clone Commander, serving in the ranks of the Grand Army during the Clone Wars. In command of the 557th Cavalry Division, Nix adjusted to the quiet world on Dantooine, as the unit was strictly used for special assignments. However, in 22 BBY, the Confederacy invaded Dantooine, prompting the 557th to assist General Mace Windu and his troops to help push them off the system. In 20 BBY, Nix and his troops were assigned to halt the production of JK-13 Droids on the world of Ord Cestus, along with General Lawen Austin and the 968th Artillery Regiment.