During the Clone Wars, RC-1207, more commonly known as Sev, served as an exceptional clone commando within the ranks of Delta Squad. In one particular operation, he and his fellow commandos were deployed via a Low Altitude Assault Transport/infantry to engage the enemy. The objective of his squad in this specific conflict was to wrest control of key areas from the opposing forces.
Sev, alongside the rest of Delta Squad, received orders to proceed to Devaron. Following the intense battle that unfolded on the planet, they located the remains of Jedi Master Halsey and his Padawan, Knox, subsequently transporting them back to Coruscant. Upon their arrival at the landing platform, they were greeted by Jedi High Council members Obi-Wan Kenobi, Plo Koon, Saesee Tiin, and Adi Gallia, who commented on the similarity between the massacre and the devastation caused by Asajj Ventress, who was believed to be deceased. Recovered security footage of the battle revealed a holographic recording of Halsey's death at the hands of an assassin who was as-yet unknown.
Sev, being a human male clone originating from Jango Fett's genetic material, stood at a height of 1.83 meters, equivalent to six feet, and was created on the planet Kamino. He possessed a strong affinity for combat, so much so that his intense enthusiasm for battle was perceived as unsettling by his Delta Squad comrades.
As a highly trained clone commando, Sev possessed a diverse array of skills and specialized training. These encompassed proficiency in both armed and unarmed combat, expertise in military tactics, infiltration techniques, reconnaissance operations, and training in the use of jetpacks. Within Delta Squad, he served as the designated sniper, and he was also renowned for his exceptional tracking and survival capabilities.
Sev and Delta Squad made their initial appearance in the 2005 Star Wars Legends video game, Star Wars: Republic Commando. During the production of "Witches of the Mist," an episode from season three of Star Wars: the Clone Wars, Dave Filoni, the supervising director, suggested incorporating Delta Squad into the storyline. The episode guide for "Witches of the Mist" officially introduced Sev's nickname into the new canon. His numerical designation, RC-1207, was formally established in canon through Jason Fry's 2021 reference book, Star Wars: The Clone Wars: Character Encyclopedia - Join the Battle!.