TX-21 is a T-series tactical droid who serves under TF-1726 and protects the Droid Factory during The Last of the Droids era. He was originally part of the Confederacy of Independent Systems serving as Poggle's personal Tactical Droid until he was destroyed by Ahsoka and Barriss. When TF-1726 rebuilt him, he was part of the New Confederacy of Independent Systems.