D'harhan, a male Niordi bounty hunter from the planet of Niorde situated within the Unknown Regions, faced a dire situation during the Clone Wars. Niorde was targeted by the Leech Legions, mercenaries hired by a rival planet in a century-long conflict. To protect his world, D'harhan and other Niordi underwent cybernetic enhancements, transforming into living artillery weapons. Despite this advantage, the Niordi were defeated, leaving D'harhan as the sole surviving weapon. He shared a history with Boba Fett, and they held each other in esteem.
D'harhan, a Near-Human Niordi scout native to the uncharted planet of Niorde, found in the Unknown Regions, lived amidst a centuries-old war with a neighboring planet. During the Clone Wars, the Leech Legion mercenaries were contracted to assault Niorde. In response, D'harhan and a select few Niordi scouts underwent cybernetic modifications, evolving into living weapons for the defense of their homeworld.
Inside a secret laboratory on the edge of the Niorde system, D'harhan's head was removed and replaced with a cannon powered by a light-mass core. His brain was cryogenically frozen and moved to a heavily armored box on his chest, while most of his other organs were removed, except for the heart and lungs, which were also relocated. The cannon was connected to his spine through neural-feed cables via a hard-splice socket between his shoulder blades. His limbs and spine were reinforced with durasteel to support the weapon drilled into his collarbones, and a tail was added for recoil stabilization. Communication was limited to a keypad voice box. An internal comm network was implemented for coordination among the living weapons. Boba Fett witnessed the entire surgery, brought to the Niorde system by Nashtah. D'harhan essentially became a life-support system for a cannon.
By the time D'harhan and the surviving Niordi scouts were ready, the Leech Legions had already conquered Niorde. D'harhan and the other living weapons attacked the enemy flagship, but only D'harhan survived. Afterward, D'harhan became a bounty hunter.
D'harhan collaborated with Fett on multiple occasions, including on Bellassa, hunting the fugitive Jedi Obi-Wan Kenobi and Ferus Olin. Together with Boba Fett, he attacked Olin, Kenobi, and Trever Flume at the Red Twins spaceport.
During the Bounty Hunter Wars, in 1 ABY, Fett recruited D'harhan for his team, which included IG-88B, Bossk, and Zuckuss. Upon arriving at the rendezvous point, D'harhan nearly attacked Zuckuss for touching D'harhan's ship. Boba Fett diffused the situation, and the two bounty hunters remarked on their long separation. The group split into two teams to travel to Circumtore to meet the Shell Hutts, with D'harhan joining Zuckuss aboard Slave I with Fett.
While D'harhan slept in the cargo hold, his cannon subconsciously tracked Zuckuss's movements, causing the Gand to seek refuge in the cockpit with Fett. Zuckuss, unnerved by the cyborg's transformation, questioned Fett about D'harhan, whom he had never heard of. Fett simply stated that D'harhan kept to himself and operated in regions of the galaxy unknown to Zuckuss.
Upon arriving in orbit around Circumtore, the Shell Hutts demanded that all bounty hunters disarm themselves before landing. D'harhan refused, arguing that he was a weapon and could not comply. Fett suggested removing his light mass core, the weapon's power source. D'harhan initially resisted, claiming his weapon was his spirit and removing it would be akin to death. Fett reassured him it would only feel like death, and real death would come later. D'harhan relented, allowing Fett to extract the core. D'harhan collapsed, declaring that Fett owed him a great debt.
After meeting with Gheeta on the planet's surface, the Hutt betrayed the bounty hunters because Fett had previously saved Emd Grahvess, the architect who designed the palace. Gheeta unleashed a large mercenary force upon them. As the mercenaries attacked, wounding Zuckuss and Bossk, D'harhan stood furious, unable to retaliate. Seeing their most powerful asset incapacitated and in danger, Fett retrieved the hidden power core, which had been placed under a dais by the architect and was revealed when Fett entered a code on his wrist. D'harhan unleashed a devastating barrage, decimating the mercenaries.
However, D'harhan's organic components began to fail under the strain. His knees gave way, and he collapsed, unable to support the cannon's weight. Fett rushed to his comrade, severing the connections from D'harhan's back, allowing Fett to wield the weapon himself. Fett eliminated the remaining mercenaries, forcing their surrender. Gheeta, enraged by the failure of his plan, confronted Fett and the mercenaries. Fett pushed D'harhan forward, placing the cannon inside the Shell Hutt's armored body and firing, liquefying Gheeta.
Fett laid the mortally wounded bounty hunter on the ground, cradling him as he died. D'harhan lamented trusting Fett, to which Fett agreed. D'harhan urged Fett to continue, and then died in Fett's arms.
Fett later reflected that he considered D'harhan to be just another part of his past that had been erased. In the Marzoon sector in 5 ABY, Fett divulged the story of D'harhan's transformation to the Assembler Balancesheet in exchange for information on a bounty.
During his planet's war, D'harhan underwent radical surgery to become a walking cannon. This weapon was reportedly capable of piercing light starship armor or vaporizing enemy infantry. His head was removed and replaced with cybernetics. The cannon, in place of his head, was bolted to his collarbones and attached to an anchoring plate in his chest. A primitive gear served as the cannon's vertical lifting mechanism. Two power cylinders flanked his metal spine, and power cables looped under his arms and around his chest. He also possessed a saurian-like cybernetic tail, segmented and long, which stabilized him against the weapon's recoil. The weapon was cooled by a primitive system dating back to the early Galactic Republic, generating steam when powered up (such as when D'harhan was angry) or firing.
Targeting sensors and indicator lights flanked the cannon, wired directly into his nervous system. The targeting sensors served as his eyes, and the cannon "looked" where D'harhan did. The indicator lights signaled his mood: yellow for standby, orange for danger, and red for firing readiness.
D'harhan's brain was relocated to an armored box in his midsection, protected by a thick chest plate. Lacking a mouth, he used a small box clipped to his belt, containing a speaker and a screen for silent text display. A keyboard allowed for slow and infrequent communication. Boba Fett mentioned that similar cyborgs communicated via an internal com-link network, presumably connected directly to the nervous system.
During "sleep," a standby function, the cannon continued to track movements and sense approaching individuals, as well as overhear conversations.