Halidrell Setsyn was a Human female. During the Cold War, she functioned as an agent for Darth Baras.
For a number of years, Setsyn managed Baras' slaving enterprise located on Nar Shaddaa. Her service to the Sith Lord began unexpectedly. She had taken over from his previous operative by deceiving the slaver out of a significant sum of credits in addition to some of his inventory, unaware of his employer. Before Setsyn could leave the planet, Baras contacted her and offered her the now-vacant position.
In 3643 BBY, Setsyn lent assistance to Baras' apprentice regarding their scheme to eliminate Dellocon, an ex-secret agent of Baras, as well as Rathari, a rival Sith Lord who was providing him protection. With Setsyn's aid, Baras' apprentice successfully disrupted Rathari's agreement with the Hutt Cartel, which led to the demise of Rathari's apprentice Girik. Later, they annihilated the Sith Lord's forces who were laying siege to the Republic outpost Shylon, which was located in Nar Shaddaa's Upper Industrial Sector. Unfortunately for Setsyn, Rathari located and attacked her base, killing her following a short fight.
Baras later conveyed his regrets over her passing and confessed that he had developed an affection for her.