Boss, also known as RC-1138, was a highly skilled clone commando sergeant who commanded the elite special forces unit Delta Squad throughout the Clone Wars, serving alongside fellow commandos Fixer, Sev, and Scorch. Some of the most perilous operations of the war involved Delta Squad, with Boss at the helm.
Bearing the designation RC-1138, the individual who would become known as "Boss" was a human clone who underwent growth on the planet of Kamino. His genetic source was the DNA of Jango Fett, a renowned bounty hunter who served as the original template for the clone trooper army. As a clone commando within the Grand Army of the Republic, RC-1138 played a role in the widespread galactic conflict known as the Clone Wars fought between the Galactic Republic and the Confederacy of Independent Systems. He held the military rank of Clone Sergeant and was the leader of the special forces team Delta Squad.
Boss and Delta Squad, whose members included second-in-command Fixer, Sev, and Scorch, were involved in some of the most dangerous missions of the conflict. On one occasion, he and his team were deployed from a LAAT/i into combat with the objective of securing a specific location. Boss and his squad were also sent to the planet Devaron after the massacre to retrieve the remains of Jedi Master Halsey and his Padawan, Knox, and transport them back to Coruscant. Upon arrival at the landing platform, the squad was greeted by Jedi Council members Obi-Wan Kenobi, Plo Koon, Saesee Tiin, and Adi Gallia, who observed that the scale of the massacre was comparable to the devastation caused by Asajj Ventress, who was believed to be dead. Recovered security footage of the battle revealed a hologram depicting Halsey's demise at the hands of an as-yet unknown assassin.
Serving as both a clone commando and a sergeant, RC-1138 was a highly capable soldier with extensive training and numerous skills. These encompassed leadership, armed and unarmed combat proficiency, military strategy, infiltration techniques, reconnaissance, sniper expertise, and jetpack operation.
When on duty, RC-1138 wore distinctive Katarn-class Commando Armor painted in a color scheme of orange and white, and he carried a backpack. In combat situations, RC-1138 wielded a pair of DC-17 hand blasters.
The character RC-1138 "Boss" made canon debut in the Star Wars universe in the season three episode "Witches of the Mist" of Star Wars: The Clone Wars, which premiered on January 21, 2011. Dave Filoni, the Supervising Director, requested that the team integrate Delta Squad into the episode's storyline during its development. RC-1138's initial appearance was in the 2005 Star Wars Legends video game Star Wars: Republic Commando, with Temuera Morrison providing his voice throughout. The nickname "Boss" for RC-1138 was established in the episode guide accompanying "Witches of the Mist," while the designation number RC-1138 was confirmed in the 2021 canon reference book Star Wars: The Clone Wars: Character Encyclopedia - Join the Battle! by Jason Fry. RC-1138's designation is yet another instance of the use of 1138 within the Star Wars franchise.