Sigma 957 is a Class-4 world with an atmosphere composed mainly of nitrogen and oxygen. Located in Sector 305, a contested region of space close to the Narn Regime, it is known as a dangerous place where the Walkers of Sigma 957 dwell. In 2260, after learning more details about the Walkers from Draal, Susan Ivanova takes the White Star there to recruit them into the Army of Light in the upcoming Second Shadow War.