DDM-38, also known as DDM or DeeDee, was a droid programmed with feminine programming that worked for General Brendol Hux at the Imperial academy located on Arkanis. After Hux joined the First Order, a splinter group from the fallen Empire, the droid continued to serve him. She went with him on a mission to enlist warriors on the devastated world of Parnassos. During a battle between the Scyre and Claw clans, DeeDee disappeared.
Brendol Hux, the commandant of the Imperial training facility known as Arkanis Academy, which specialized in the education of future officers, had a droid called DDM-38. DDM's duties at the academy included guiding cadets and preventing them from entering prohibited zones, such as Area Null. The cadets also thought DDM was in charge of keeping an eye on any communications that went off-world. DDM welcomed Zare Leonis when he was transferred from Lothal to Arkanis, leading him to his living quarters and answering his questions along the way. Upon entering the room, DDM activated the lights, thus awakening the sleeping cadets. Some days later, DeeDee discovered Zare attempting to tail Anya Razar and a number of cloaked members of the Commandant's Cadets, a clandestine organization established by Commandant Hux, as they entered Area Null. Anya was undergoing induction into the Commandant's Cadets following the successful completion of a perilous test. She scolded Leonis for being out of his dormitory at night and informed him that he would receive demerits. Unbeknownst to DDM and her master Hux, Leonis was secretly a rebel sympathizer who had infiltrated the Arkanis Academy to locate his missing sister, Dhara Leonis, who had been forced into a secret program known as Project Harvester.
The next day, DDM escorted Leonis to a private meeting with the Grand Inquisitor after they had finished eating dinner. She guided Zare to the Commandant's balcony, the location of the meeting. The Inquisitor questioned Leonis regarding his attempt to access Area Null. Before he could press the cadet further, DeeDee interrupted to notify the Grand Inquisitor that he had received an urgent, encrypted message from the planet Lothal. The Inquisitor left for Lothal to deal with the Spectres, but he was killed during a confrontation in the Mustafar system.
A few days later, DDM, acting on Commandant Hux's orders, summoned the Arkanis cadets to the cliffside. There, the assembled cadets witnessed a sea monster consuming a wandering nerf that had strayed onto the beach. Commandant Hux used this event to illustrate the significance of discipline and natural selection in training.
After a military exercise on Sirpar, Zare found out that he had been invited to join the Commandant's Cadets, but he also learned that he had to murder his classmate Penn Zarang to complete the trial. Leonis shared this information with his mentor, Lieutenant Chiron, who had been dispatched by Grand Moff Wilhuff Tarkin to investigate reports that Hux was forming a secret society that operated outside of the Imperial Military hierarchy. Chiron devised a strategy to fabricate Zarang's death by burying a decaying piece of nerf in a makeshift grave. Chiron arranged a "special assignment" for the droid in order to prevent DeeDee from becoming suspicious. This allowed Chiron, Leonis, and Zarang to carry out their plan.
The following evening, DeeDee stood by Commandant Hux during a banquet held to celebrate Leonis's acceptance into the Commandant Cadets. She silently watched her master address the cadets about his ideas for improving the Empire's stormtroopers while Hux gave his speech. Before Leonis could be formally inducted, Beck Ollet, his former friend who had undergone a re-education program called Project Unity, revealed him to be a traitor.
DDM sat next to her master Hux the following day during a military tribunal that was held to try Zare Leonis. The cadet admitted guilt to all accusations made against him, including treason and false enlistment, but he also used the chance to deliver a speech in which he denounced the Empire. Leonis was kicked out of the military and sentenced to death by Colonel Julyan. However, he was able to escape with his sister Dhara because of a rescue operation planned by Merei Spanjaf and the Spectres.
Around 24 ABY, DDM-38 accompanied Hux on a journey to the ruined planet of Parnassos in order to find warriors to join the First Order, a leftover organization of the Old Empire. Hux had advanced to the rank of general in the First Order at this point and was in charge of their stormtrooper training program. Hux's ship was shot down by the planet's automated defense system as they approached Parnassos. DDM, Hux, and three stormtroopers were able to leave the damaged ship in an escape pod that landed in the wasteland between the territories of the rival Scyre and Claw clans.
The Dug Balder, who led the Claws, saved DDM-38, Hux, and the stormtroopers. DDM served as Hux's translator because the locals spoke a distinct variation of Galactic Basic Standard. Hux promised the impoverished residents supplies and technology in exchange for their help in getting him to his ship, which had crashed on a different area of Parnassos. Phasma, the Scyre military leader, and her warriors attacked the Claws in an effort to obtain these supplies and technologies, killing Balder and eleven of his men.
Even though Phasma was successful in evacuating Hux and his stormtroopers, DDM was lost in the chaos. Phasma was able to find one of the droid's legs, which was then used to make a prosthetic leg for her brother Keldo, the leader of the Scyres. Ten years later, the Resistance spy Vi Moradi told the First Order stormtrooper Captain Cardinal, a rival of Captain Phasma, about the incident.
DDM-38 had jet-black plating and a head that featured a blank, metal faceplate with a pair of black photoreceptors. According to Phasma, the droid was humanoid in shape and constructed of matte-black metal. DDM used legged locomotion to move, and she possessed at least one hand that was both cold and unyielding. The droid had trouble climbing plateaus because of its weight and inability to climb.
She was programmed with feminine characteristics and spoke in a somewhat feminine, monotone voice. DDM occasionally disregarded Zare Leonis's questions and interrupted him when he first arrived on Arkanis. The droid typically walked at a deliberately slow pace, but she quickened her pace when she later escorted Leonis to see the Grand Inquisitor.
DDM was responsible for enforcing Commandant Hux's authority and regulations throughout the Arkanis Academy. She frequently patrolled the academy grounds at night and gave demerits to cadets who were out past curfew. DDM appeared to lack a distinct personality and was completely committed to carrying out her master's wishes and directives. DDM-38 also served as General Hux's translator droid by the time of the First Order, and she was able to comprehend the variation of Galactic Basic spoken by the inhabitants of the devastated planet of Parnassos.
DDM-38 made her debut in Servants of the Empire: The Secret Academy, the last book in the Servants of the Empire series for young readers. Jason Fry wrote The Secret Academy, which was released by Disney–Lucasfilm Press on October 6, 2015. In Delilah S. Dawson's 2017 novel Phasma, which was created as part of the Journey to Star Wars: The Last Jedi promotional campaign, an unnamed droid that resembles DDM-38 makes a brief appearance. Similar to DDM-38, the droid is described as having a humanoid form with limbs and being made of matte-black metal.