Corporal Derdram held a position within the Internal Security Branch of Imperial Intelligence by the year of 3 ABY. Simultaneously, he served in the Imperial Navy during that same year. Derdram's assignment placed him aboard the Executor-class Star Dreadnought known as the Executor, where he was responsible for the physical protection of Imperial personnel, guarding them against Rebel Alliance saboteurs.
Within the Galactic Empire's Navy, Derdram, a Human male, served by 3 ABY. He had become a member of Imperial Intelligence, specifically assigned to its Internal Security Branch also by 3 ABY. By this time, he had achieved the rank of corporal and was stationed on the Executor, an Executor-class Star Dreadnought that acted as the flagship for the Dark Lord of the Sith, Darth Vader. The purpose of Derdram's assignment on the Executor was to safeguard Imperial personnel from potential attacks by Rebel Alliance saboteurs.
Following the events of the Battle of Hoth in 3 ABY, Derdram found himself stationed within the crew pits of the command bridge on another Imperial starship. This vessel was the Imperial II-class Star Destroyer called the Avenger, commanded by Captain Lorth Needa and part of Vader's own Star Destroyer fleet, Death Squadron. The Avenger engaged in the pursuit of the escaping YT-1300 light freighter, the Millennium Falcon, through the Hoth system after the Battle of Hoth. During this chase, the Falcon's actions nearly caused the Avenger to collide with another Star Destroyer. The Avenger continued its pursuit into the Hoth asteroid field, sustaining considerable damage as it navigated the asteroid field in search of the Falcon. As the Avenger followed the Falcon into the adjacent Anoat system, the freighter made a direct run towards the bridge, prompting Derdram and his fellow crew members in the crew pits to seek cover, triggering alarms throughout the Avenger.
The sensors of the Avenger lost track of the Millennium Falcon, unaware that the freighter had simply landed in a blind spot on the Star Destroyer's conning tower. When Darth Vader requested an update on the Falcon's pursuit, Needa made the decision to personally apologize to Vader for the apparent failure to capture the Falcon. He boarded a TIE/sh VIP shuttle to reach the Executor, where he was executed by Vader for his failure. The Star Destroyers of Death Squadron ultimately jumped into hyperspace, scattering in their search for the Falcon, unaware that the freighter remained hidden on the Avenger's conning tower. The Avenger prepared to enter hyperspace in a direction opposite to the rest of the fleet, first ejecting its garbage into space. The Falcon seized this opportunity to escape, drifting alongside the refuse and successfully evading the Imperial fleet.
While serving in the Imperial forces, Derdram was seen wearing a black Imperial Navy crewman's uniform.
Derdram's initial appearance was in the 1980 original trilogy movie, Star Wars: Episode V The Empire Strikes Back. His scenes were filmed on Stage 5 at Elstree Studios sometime between April 24 and May 2, 1979. Although he was not credited in the film, Ralph Morse has stated that he played the character. At the film's conclusion, Ralph Morse, along with other extras from the Avenger, can be seen on the Executor because footage from the former Star Destroyer was reused for a later scene.
The Derdram character was officially named on a card included in the Dagobah Limited expansion for the Star Wars Customizable Card Game in 1997. The lore established him as being aboard the Executor, however, the image used on the card is a still photograph of Ralph Morse taken from the Avenger scenes in The Empire Strikes Back. Due to the card's use of an image from the Avenger scenes to depict Derdram, this article only suggests that Derdram is the character aboard the Avenger and does not explicitly confirm a connection to the character on the Executor.