"Cipher Twelve" represented the call sign used by a male Imperial Agent serving within Imperial Intelligence of the Sith Empire that had resurgent.
Sometime before a specific date, he achieved the rank of Cipher Agent. He was considered a veteran operative, having served before the Great Galactic War. Throughout his career, he developed connections among those on the periphery of society. Doctor Eckard Lokin is known to have collaborated with the Cipher at one point, stating that Cipher Twelve was an agent of the highest caliber. By the time Cipher Twelve received his Mandalorian brands, he had become verbally abusive in private.
In the end, fate turned against him, and a Hapani royal assassin fatally wounded him by piercing his lungs. Later agents were unaware of his existence, as Imperial Intelligence rarely discussed the history of prior Cipher Agents. During the Cold War, Eckard Lokin recalled the death of Cipher Twelve on the thirtieth anniversary of his passing, while sharing his history with Cipher Nine.