Mosh Barris held the rank of colonel within the Imperial Army. He served as the chief troop commander on the Venator-class Star Destroyer known as the Strikefast. During the Imperial Era, Barris undertook an investigation of an uncharted planet where an alien settlement was detected, adhering to the Empire's established Unknown Alien protocols. However, upon arrival at the planet, Imperial forces faced a relentless assault from an unidentified alien adversary, resulting in the deaths of numerous troops under Barris' command. Consequently, Barris was compelled to evacuate his forces and seize the settlement for examination aboard the Strikefast.
Upon discovering their return, Captain Parck, who commanded the Star Destroyer, exposed the alien who had been concealed on the troop carrier. The alien was apprehended and identified himself as Thrawn, a member of the Chiss species. Due to his strategic value, Thrawn was transported to Coruscant to be presented as a gift to Emperor Sheev Palpatine.
During the Imperial Era, Colonel Mosh Barris found himself stationed on the Strikefast, a Venator-class Star Destroyer under the command of Captain Voss Parck. Their mission of escorting several Imperial cadets back to the Myomar Academy in the Expansion Region took an unexpected turn when they pursued smugglers, leading them to an uncharted planet where an alien dwelling had been discovered. In accordance with the Unknown Alien protocols, the Imperials were assigned the task of investigating the site and establishing contact with any previously undiscovered alien life forms. Leading a landing party to the site, Colonel Barris came across a clearing in the forest, at the center of which was a hunt surrounded by eight rectangular boxes bearing two distinct sets of markings in an unknown language.
Unable to decipher the script, Barris and his team summoned Eli Vanto, an Imperial cadet from the Strikefast, to assist in the investigation. Vanto, proficient in multiple languages, quickly identified the script on the boxes as Sy Bisti, a trade language employed on the planet Lysatra in Wild Space. However, he was unable to interpret the second set of script. Expressing his discontent, Barris voiced his frustration with having to survey the site in compliance with the Unknown Alien protocols, which he derisively considered a vestige of the Old Republic. Despite his personal feelings, Barris adhered to Captain Parck's directives to establish a camp while a tech analysis team was dispatched.
Shortly thereafter, Major Wyan informed Colonel Barris of the discovery of a crashed Imperial V-wing starfighter. With Captain Parck's approval, Barris and an Imperial Navy trooper proceeded to the crash site, returning with the pilot's flight suit, which had been filled with grass, leaves, and pyussh berries. Barris reported to Captain Parck that they had found no trace of the pilot. Barris also informed Parck and Vanto that he had established a troop perimeter around the settlement and deployed an additional platoon of troopers from the Strikefast.
After Parck instructed Barris and his troops to locate the pilot's body, Barris suggested that they might have to wait until morning. When Parck inquired if his soldiers were afraid of the dark, Barris responded that he and his men had discovered that the V-wing pilot's blaster, spare power packs, and concussion grenades were missing. Parck then decided to suspend any search operations until morning to prevent friendly fire incidents. Barris and his troops were instructed to remain in camp until daybreak. Barris then remarked that he hoped that whoever took the grenades would blow themselves to pieces before attacking them. Before leaving, Captain Parck instructed Cadet Vanto to stay with Barris' team to study the settlement.
By dusk, Barris's troops had completed the construction of their perimeter. The tech team also set up an examination table protected by a transparent weather canopy so that they could study the grass and leaves taken from the flight suit. Shortly later, Major Wyan and his search party returned empty-handed. While examining the flight suit, Barris found the pyussh berries and speculated that they were used in some kind of religious ritual. At that point, Barris and his troops were startled by two explosions along the perimeter line. The second explosion slammed flat against Barris' face and caused the grasses and leaves on the examination table to burn. Barris' troops visited the source of the explosions and reported that the unknown attacker had fled.
Barris also contacted Captain Parck and got him to dispatch some V-wings for a grid search. He then ordered Major Wyan to take a squad to set up some floodlights at the perimeter and then fine-mesh the hemisphere sensor screen. Wyan responded that the perimeter was full of birds and small ground animals and warned that fine-meshing the screen too far would trigger the alarms. Barris accepted Wyan's explanation and ordered him to set up the floodlights. Before they could do that, a second V-wing crashed nearby. Barris and his men found the fallen pilot but discovered that his blaster, power packs, and concussion grenades had been taken.
Alarmed by the attacks, Colonel Barris consulted with Captain Parck via comm at midnight and received authorization to examine the first flight suit. It was then that they discovered that the helmet's comlink was missing. Wyan, however, noted that the second pilot's comlink was still present. Wyan speculated that the attackers were tampering with their circuit. In response, Colonel Barris contacted the Strikefast to request that the circuit be shut down. Shortly thereafter, Vanto, who had been analyzing the recent attacks, informed Barris that he had discovered a couple of coins between the inner and outer shells of one of the crates that dated back to before the Clone Wars. After debating the motives of the mysterious attacker with Wyan and Vanto, Barris instructed Vanto to continue studying the crates.
By dawn, Barris' landing party had suffered the loss of five Navy troopers, who were guarding the sentry perimeter. Three of them had been killed by the mysterious enemy using concussion grenades while two others had been killed in friendly fire incidents. Barris requested two squads of stormtroopers from the Strikefast, who arrived at dawn. While the stormtroopers were search the perimeter, Colonel Barris found that the mysterious attacker was jamming their comlink channels. Disturbed by the repeated attacks, Barris announced that the Imperial landing party would be withdrawing. When Wyan reminded him about the Unknown Alien protocols, Barris responded that they could bring the settlement and crates back aboard the Strikefast.
While the Imperial Navy troopers and technicians began removing the settlement and crates, Barris waited for the anticipated attack, which did not occur much to his bafflement. When the stormtroopers returned, Barris noticed that one of them was missing. Barris ordered the technicians and Navy troopers to evacuate with the settlement and crates aboard their transport while the stormtroopers boarded their own troop carrier. However, one of the stormtroopers was standing rigid outside the hatchway. Before Barris and his men could respond, the trooper exploded. The Imperials discovered that the armor was empty. Shortly later, three stormtroopers emerged from the clearing with the body of their fallen comrade.
Upon landing in the Strikefast's hangar bay, Colonel Barris was confronted by Captain Parck, who was displeased that he left the site without permission. Barris responded that he was commander of the site and was only doing what he deemed best. Before Barris could order his technicians to erect the site, Captain Parck ordered Barris and Vanto to accompany him to the hangar bay control tower. Realizing that the intruder had accompanied the landing party, Parck then darkened the hangar bay's lights to ferret them out. After two hours, Barris and the others witnessed a humanoid figure emerging from the transport and attempt to stow aboard one of the park Zeta-class shuttles. Imperial troops then apprehended the prisoner and brought him before Parck, Barris, and Vanto. The attacker was a blue-skinned Chiss warrior who introduced himself as Mitth'raw'nuruodo (or "Thrawn" in short form).
While Parck and Vanto questioned Thrawn, an enraged Barris interjected and demanded to know why he had harassed and killed his men. When Thrawn responded that it was necessary in Sy Bisti, Barris insisted that the alien respond in Galactic Basic Standard. Thrawn then claimed that he had been exiled to the planet by his own people and that he hoped to return home. When questioned further by Vanto, Thrawn added that he had been purportedly exiled since he and his people's leaders disagreed about preemptive strikes. Thrawn then confirmed that he had discovered the body of the first V-wing pilot and filled it with grass and berries.
Barris and the others listened as Thrawn recounted how he had attacked the Imperial camp by sending small animals strapped with blaster power packs to the perimeter. Thrawn also admitted attacking the Imperial sentries by using a sling to fling berries at them and downing the second V-wing fighter with a monofilament line. As Thrawn elaborated how he had used the stolen Imperial communications equipment to attack the landing party, Barris expressed anger that Thrawn had killed a man so that he could steal his comlink.
When Barris asked if Thrawn had attacked his men for the fun of it, Thrawn expressed regret but explained that he wanted to draw stormtroopers out. Thrawn admitted infiltrating the camp in stormtrooper armor and jamming the Imperial comlinks in order to board the transport and hide within the second power generator casing. Barris was present when Thrawn elaborated his interest in seeking an alliance with the Empire.
When Captain Parck brought Thrawn before Emperor Palpatine at the Imperial Palace on Coruscant, Colonel Barris accompanied Parck, Thrawn, Eli along with three navy troopers and stormtroopers who had been deployed on the uncharted world. Barris and the others were present when Thrawn offered his services to the Emperor as his adviser on the Unknown Regions. The Emperor was impressed enough by Thrawn's offer to assign him a place at the prestigious Royal Imperial Academy. Per Thrawn's request, the Emperor agreed to transfer Eli Vanto to the Royal Imperial Academy to serve as Thrawn's translator. Following the meeting, Barris and the others went back to their duties. Over the years, Thrawn and Vanto would become friends and rise through the ranks of the Imperial Navy with the former being promoted to Grand Admiral after ending the Batonn sector insurgency.
Mosh Barris, a male human officer within the Imperial Army, held the rank of Colonel. Barris demonstrated a lack of knowledge regarding foreign languages, dismissing Sy Bisti as an obscure tongue unworthy of even droids' attention. He failed to recognize Sy Bisti as a well-defined and valuable language spoken in the remote Wild Space region. Similar to many Imperial officers, Barris viewed the Unknown Alien protocols as an inconvenient relic of the Old Republic that hindered the Imperial Military's operations. His reluctant compliance with the UA protocols led him to abandon his post on the uncharted world and transport the settlement back to the Strikefast.
Colonel Barris was deeply shaken by Thrawn's assault on his Imperial landing party, which resulted in the deaths of five navy troopers and two stormtroopers. Barris appeared to only understand Galactic Basic Standard and demanded that Thrawn speak the language during the interrogation. Unlike Captain Parck, Barris was not impressed by Thrawn's resourceful military tactics. Barris proved to be an ineffective commander since he was unable to cope with Thrawn's irregular warfare.
The character of Mosh Barris made his debut in "Mist Encounter," a short story penned by Timothy Zahn and featured in Star Wars Adventure Journal 7 in August 1995. "Mist Encounter" delved into the initial encounter between Thrawn and members of the Galactic Empire within the Star Wars Legends continuity. Subsequently, Barris reappeared in Zahn's 2017 novel Thrawn, a reimagined canonical origin story of the titular character that incorporated elements from the "Mist Encounter" narrative. Barris's dialogue is presented from the perspective of Eli Vanto, the novel's deuteragonist.
Within the e-book edition of Thrawn, Mosh Barris is later erroneously referred to as major, while still retaining the rank of colonel. This error stemmed from editorial alterations made to the novel.