Dek-Nil

Doctor Chelli Aphra reprogrammed the droideka who would become known as Dek-Nil, installing probability tech and modifying his existential circuits. Aphra implemented a false control circuit to prevent restraining bolts from dominating the droid, concealing the actual one behind beskar armor. Around 3 ABY, Dek-Nil was selected by the assassin droid 0-0-0, head of the Son-tuul Pride syndicate, to be part of a team assembled for a mission to Skako Minor in order to find his lost memories. Upon the crew's arrival on Skako, the Skakoan Hallio Bas revealed his betrayal, leading them into an Imperial ambush. Aphra eliminated Bas and the Imperials using Flufto, an explosive tooka she had cloned.

The crew was able to press on with their task, breaking into the workshop of Wat Tambor. Dek-Nil detected Magna Tolvan's Delta-class T-3c shuttle just before it crashed into the workshop, which awakened a chthonic worm god. During the ensuing battle, Dek-Nil fired a shot that caused a stormtrooper to accidentally collapse the ceiling onto the worm god, killing it. Before leaving Skako Minor, the crew plundered the workshop's remains. However, Aphra discovered that 0-0-0's memories were stored on the Tarkin Initiative space station known as Hivebase-1.

Using jump signatures found in Tambor's files, the crew managed to locate the Rebel Alliance flight school, Lucrehulk Prime. The Rebel officer Bini mistook the crew for recruits and gave them a tour of the school. When Sister Six inquired about the whereabouts of the Defel Glahst Ombra, Dek-Nil made the cryptic prediction that Magna Tolvan was wearing Ombra's fur as a disguise, and he broke a pipe that began to leak onto the floor. Subsequently, General Hera Syndulla discovered the crew's true nature as mercenaries and had them imprisoned. As Dek-Nil predicted, Tolvan entered his and Aphra's cell wearing Ombra's fur. During Tolvan's threatening interrogation of Aphra, the leaking pipe that Dek-Nil had broken caused an electrical surge that knocked Tolvan unconscious and unlocked the prison cells. The crew escaped the Lucrehulk-class Battleship, capturing General Syndulla as a hostage.

Upon reaching Hivebase-1, Aphra used Syndulla to deceive the Imperials into allowing them to board and to lure the Lucrehulk Prime into pursuing them, which resulted in a skirmish with the Imperial forces. Before they could finish their mission, Tolvan alerted Commander Yewl to their presence, prompting Yewl to thaw the prototypes stored on the station. One of these prototypes shot Dek-Nil, seemingly destroying him.

However, Dek-Nil had only feigned his demise. He proceeded to sabotage the station's registry, altering its firing patterns, before firing at the scaraphyte swarm surrounding the station, causing it to behave erratically. Dek-Nil's sabotage of the registry tricked one of the Imperials into uttering the codeword that activated Aphra's exploding tookas, which had been released throughout the station. The crew successfully completed their mission and stole the data from the station, but Dek-Nil was later captured by Tolvan, who sent him to Accresker Jail with Aphra.

Upon his arrival at the wreckage-prison, Dek-Nil was repurposed as one of the facility's many hubdroids. The Galactic Empire tried to reprogram Dek-Nil by applying a restraining bolt, but Aphra had concealed his actual control circuit behind a solid beskar shield. After being assigned a squad, Dek-Nil orchestrated the deaths of his squad members in what appeared to be improbable accidents. During an attack on a Rebel Alliance EF76 Nebulon-B escort frigate, Dek-Nil encountered Aphra and her squad, who had previously sabotaged and destroyed their hubdroid. Dek-Nil rescued Aphra, along with the apparent shape-shifter "Lopset Yas" (who was actually the disguised rogue surgeon Cornelius Evazan), by transferring their proximity bombs to himself, preventing their detonation. Despite detecting a third lifeform, Dek-Nil transferred the two convicts into his squad.

Aphra led Dek-Nil and Yas toward an escape pod that was jammed on the edge of the prison's airdome. However, before they could board, a Force spirit mysteriously moved Dek-Nil's restraining bolt into position. With the restraining bolt engaged, the Imperial programming took control of his actions, and Dek-Nil destroyed the escape pod, forcing Aphra and Yas to return to Accresker Jail. Aphra was later taken for interrogation, during which Dek-Nil suggested several methods to overcome Aphra's resistance to the mind probe. On their way back to the prison, Aphra pleaded with Dek-Nil, hoping he was pretending to be under Imperial control, but the droideka silenced her and ordered her back to her quarters.

Not long after the battle, Dek-Nil and another hubdroid detected a broadcast originating from the prisoners' quarters and set out to locate it. Their search proved unsuccessful, and soon after, the prisoners were tasked with attacking another target. The prison arrived at the scene of three Imperial-class Star Destroyers that had disabled a pirate station as part of the Empire's bandit purges. The prisoners were released to lay siege to the stranded pirates, with Dek-Nil leading Aphra and Yas into the fray. As they charged into battle, Aphra used Imperial authority code 6690B1 on Dek-Nil, overriding his restraining bolt and forcing him to take them to a rendezvous point where Magna Tolvan had arrived to pick them up.

As Aphra and Yas were about to escape aboard Tolvan's TIE fighter, their plan was thwarted by the Force spirit, which destroyed the sensor disruptors before leading Aphra to the abandoned wreckage of a Penumbra-1 shattersprite. Distracted by the ancient Jedi craft, Aphra went to investigate, and Dek-Nil followed. However, upon reaching the ship, the spirit disassembled Dek-Nil with the Force, scattering his components. Aphra discovered that the spirit's existence was due to gundravian hookspores mutated by the Force, but Aphra and Yas were forced to retreat due to the receding airdome. Yas took Dek-Nil's central processor with them to safeguard their proximity bombs, and continued to carry it as they were forced back to the prison.

After Aphra was compelled to reveal the hookspore infestation during an interrogation by the Mairan Bor Ifriem, the Accresker command abandoned the prison, setting its course to crash into the Rebel Alliance-affiliated planet Tiferep Major. Aphra, Tolvan, Yas, and their associate Sana Starros broke into the wreckage of the Arquitens-class tug cruiser, and Yas carried Dek-Nil's central processor on his back. Once inside, Aphra asked Yas for the piece of Dek-Nil, which she used to slice into the generator controlling the gravity in the prison. After she was done, Yas retrieved Dek-Nil's head and carried it with him once more.

Yas was still carrying the piece of Dek-Nil when Aphra froze him in his natural appearance as Evazan, intending to trick the vigilante Tam Posla into trading what she believed was a shape-shifter for an escape shuttle. Posla later realized he had been deceived and returned to Accresker. Yas accompanied him, using Dek-Nil to track Aphra's proximity bomb. Yas continued to carry Dek-Nil on his back even as he stunned Aphra and took her captive aboard Posla's ship. By the time he revealed his true identity as Evazan to her, he was no longer carrying the droid.

As a probability droid, Dek-Nil possessed the ability to foresee events and trigger chain reactions with predictable outcomes. His modified existential circuits caused him to constantly make philosophical remarks on the marvels of existence, which others found peculiar.

Despite being a droideka, Dek-Nil underwent significant modifications, possessing only one arm equipped with a blaster cannon powerful enough to destroy an entire escape pod in seconds. He was altered to include a decoy control circuit, with the actual circuit protected by beskar plating, preventing restraining bolts from affecting him. He was assembled from mismatched parts, including the head of an astromech droid. Upon arrival at Accresker Jail, he was fitted with a restraining bolt and assigned as one of the prison's hubdroids, but his decoy control circuit shielded him. He was later controlled by the Imperial programming, but Aphra freed him from it.

Dek-Nil made his debut in the 2017 canon comic Doctor Aphra (2016) 15, authored by Simon Spurrier and illustrated by Emilio Laiso.