T-12 was a service droid used by the Jedi to catalog Naddist artifacts being shipped to Ossus following the Freedon Nadd Uprising. During the Conclave at Deneba, T-12 was present, assisting Cay Qel-Droma and the other Jedi. When the Krath attacked Deneba during the conclave, T-12 was one of the droids subjected to the Krath programming trap, thus turning T-12 from a humble servant droid into a deadly assassin.
- Tales of the Jedi: Dark Lords of the Sith 1: Masters and Students of the Force (First appearance)
- Tales of the Jedi: Dark Lords of the Sith 3: Descent to the Dark Side
- "Straight from the Horse's Mouth: A Guide to the Star Wars: Tales of the Jedi Universe, Part 3"—Star Wars Insider 28
- The Complete Star Wars Encyclopedia