Barrow Oicunn began his career as an officer within the Republic Navy and later achieved the rank of admiral within the Imperial Navy. At the onset of the widespread Clone Wars across the galaxy, Oicunn became a member of the Humbarine sector defensive forces, which had recently come under the control of the Galactic Republic's war council. Oicunn's planet of origin, Humbarine, was repeatedly attacked by the Confederacy of Independent Systems, leading the junior officer to implement innovative strategies while adhering to Republic regulations. As the conflict intensified, the Republic diverted resources from Humbarine's defenses, which then resulted in a devastating assault by the Separatists' Supreme Commander, Grievous. Oicunn's entire family died during the pivotal Battle of Humbarine, and the planet was abandoned, compelling Oicunn to question his faith in the government and to serve with the primary Republic Navy.
While serving with the Coruscant Home Fleet, Oicunn encountered his sector's representative, Bana Breemu, who recognized him as a hero of Humbarine. He was stationed aboard the Mas Ramdar during the Battle of Coruscant, and continued his service to the Republic, despite his growing disillusionment with their methods. Oicunn embraced Palpatine's New Order, as he was under the impression that a Galactic Empire would be better equipped to ensure peace and justice throughout the galaxy. The lieutenant held the leaders of the new regime in high regard, and quickly advanced through the ranks of the Imperial Military, eventually attaining the rank of admiral.
Barrow Oicunn, a Human male, was born on the world of Humbarine. In 22 BBY, the Clone Wars erupted between the Galactic Republic and the Confederacy of Independent Systems. This widespread galactic war would eventually reach Oicunn's homeworld. Wanting to contribute to the war effort, Oicunn enlisted in the Humbarine sector defense forces. These forces had been restructured and absorbed by the Republic's war council, subjecting them to the standards and procedures of the galaxy's leading government. As Humbarine faced constant attacks from the Confederacy, Oicunn, despite his low rank as a junior officer, had the opportunity to employ inventive tactics to repel the enemy.
As Humbarine remained a battleground over the years, the Republic was compelled to withdraw forces from the ecumenopolis and redirect them to more critical areas. Consequently, Grievous, the Supreme Commander of the Separatist droid armies, decided to strike, launching a full hour of orbital bombardment from his flagship, the Providence-class carrier/destroyer known as the Invisible Hand, which melted the planet's surface and decimated its population. Oicunn's family was killed in the resulting chaos, which severely undermined the junior officer's faith in the Republic. He lost confidence in the government's ability to maintain peace and security across its member planets. With Humbarine devastated and abandoned, its defense forces were disbanded, and Oicunn was reassigned to the Coruscant Home Fleet.
While assigned to the Home Fleet, Oicunn served as a gunnery officer aboard the Dreadnaught-class heavy cruiser Mas Ramdar. During his off-duty hours, he stayed on Coruscant and formed a friendship with Bana Breemu, the senator representing the Humbarine Sector. Oicunn shared the unfortunate fate of Humbarine with the representative, and in response, Breemu declared him a hero of his homeworld. This recognition lifted Oicunn's spirits, and he soon had the chance to avenge his loved ones in the Battle of Coruscant.
In 19 BBY, General Grievous launched a devastating attack on Coruscant. During this assault, he kidnapped Supreme Chancellor Palpatine and attempted to escape the capital aboard the Invisible Hand. However, as he prepared to depart, the Mas Ramdar intervened to prevent its retreat after inflicting significant damage on several Confederate warships. Oicunn seized the opportunity to destroy the source of Humbarine's destruction, as the Mas Ramdar exchanged heavy turbolaser fire with the Invisible Hand. Nevertheless, the Mas Ramdar was eventually forced to withdraw, as the Invisible Hand, being a larger vessel, possessed superior firepower. The Jedi ultimately rescued Palpatine, securing victory in the battle. As a result of his exceptional service and unwavering loyalty to the Republic despite the Humbarine tragedy, Oicunn was assigned to a more prestigious position: serving aboard one of the Venator-class Star Destroyers guarding the construction of the top-secret Death Star superweapon.
The Clone Wars concluded shortly after the Battle of Coruscant, and Chancellor Palpatine, having consolidated his power, transformed the Republic into a Galactic Empire. Oicunn welcomed the new Emperor's policies, believing that a strong governing entity could prevent tragedies like the one that befell Humbarine. Rumors of a Jedi rebellion concerned him, but he did not consider it a significant threat, confident that the New Order would ensure peace and justice throughout the galaxy. Shortly after the declaration of a New Order, Emperor Palpatine himself, Lord Vader (the new Supreme Commander), and Moff Wilhuff Tarkin visited the Star Destroyer where Lieutenant Oicunn was stationed, to inspect the construction of the Death Star battle station.
The lieutenant held this leading triumvirate of the Empire in high esteem, and as the years passed, he advanced through the Imperial Navy's ranks. At some point, Oicunn achieved the rank of captain and became a pilot of a VT-49 Decimator. He eventually rose to the rank of admiral and proudly served as a new clone template for future stormtrooper units. Years later, Admiral Oicunn experienced some unexplained misfortune related to the Kessel Run, which was later mentioned in a report to Grand Vizier Sate Pestage by Commander Maximillian Seerdon.
Barrow Oicunn was extremely loyal and faithfully served his superiors, regardless of his personal feelings. He adapted to restrictive doctrines while serving in the Humbarine Sector defense fleet, developing tactics that were considered "inspired." The devastating loss of Humbarine shook his faith in the Republic, but he continued to fight the Confederates. Oicunn believed that the Republic, in its current state, could not effectively defend its member planets, so he welcomed the arrival of the New Order and the Galactic Empire. As he climbed the Imperial ranks, Oicunn was regarded as a model soldier who exemplified an ideal combination of loyalty to his ruined homeworld and allegiance to the Galactic Empire.
The character of Lieutenant Oicunn initially appeared as an extra in the closing montage of George Lucas' film, Star Wars: Episode III Revenge of the Sith. Daniele F. later provided Oicunn with a backstory through the "What's The Story?" feature on StarWars.com's Hyperspace. Daniele F. chose to connect Oicunn to the deleted scenes of Revenge of the Sith, which explains the character's ties to Bana Breemu and Humbarine. James Floyd provided the first name "Barrow." Oicunn was later included in an entry in The Complete Star Wars Encyclopedia.