Sublieutenant Setal was a low ranking Romulan logistics officer. In 2366, Setal served under Admiral Alidar Jarok.
When Alidar Jarok defected to the Federation, he posed as Setal so he could feign to have limited intelligence concerning Romulan military operations. (TNG: "The Defector")
The real Setal was never shown.
According to the script, Setal was pronounced as "see-TALL". In a deleted scene, it was mentioned that Setal was assigned to Sector 814.