- "Our scout ships have reached Dantooine. They found the remains of a Rebel base, but they estimate that it has been deserted for some time. They are now conducting an extensive search of the surrounding systems."
- ―Siward Cass reports to Grand Moff Wilhuff Tarkin
Fifteen years into the Emperor's reign, the human male Siward Cass held the Imperial rank of major, and the officer served as an aide to Grand Moff Wilhuff Tarkin, governor of the Outer Rim Territories. At the time, there were rumors that Commandant Brendol Hux had created a secret society within the Arkanis Academy. On Tarkin's order, Cass transferred Lieutenant Chiron from the Academy for Young Imperials on Lothal to Arkanis so he could investigate the matter. The major notably made sure that Chiron's code cylinder would give him access to Area Null, a restricted part of the academy where the Empire ran a number of secret programs.
The Death Star
Siward Cass was still serving under Tarkin during the Galactic Civil War, which pitted the Empire against Alliance to Restore the Republic. At this time, he was a chief. Shortly before the Battle of Yavin, the Imperial Army officer attended a meeting on board the Death Star in which he witnessed Admiral Conan Antonio Motti and General Cassio Tagge argue about the station's power, before the Sith Lord Darth Vader Force choked Motti. He later reported to Tarkin that the planet Dantooine was not the location of the main Rebel base. Not too long afterward, the Battle of Yavin commenced, with the Alliance destroying the Death Star battle station.
Behind the scenes
Siward Cass first appeared portrayed by English actor Patrick Jordan in the 1977 original Star Wars film Star Wars: Episode IV A New Hope, the first installment of the original trilogy. Though unnamed in the movie itself, he was referred as "Cass" in Alan Dean Foster's novelization. Jordan got the part of Cass in A New Hope through his friendship with Alec Guinness, who portrayed Obi-Wan Kenobi and whom had worked with Jordan for The Old Vic company in the 1940s. However, Jordan shared Guinness' contempt for the film, dubious about the film's prospects.
- Servants of the Empire: The Secret Academy (Mentioned only) (First identified as Cass)
- Star Wars: Episode IV A New Hope (First appearance)
- Star Wars: A New Hope junior novelization
- Star Wars: The Original Trilogy – A Graphic Novel
- "An Incident Report"—From a Certain Point of View (Mentioned only) (First identified as Siward)
- From a Certain Point of View audiobook (Mentioned only)
- Star Wars Helmet Collection 1 (Weapons & Uniforms: Imperial High Command) (Picture only)
- Star Wars Helmet Collection 34 (Helmets: Death Star Trooper) (Picture only)