Coburn Sear served as a male Colonel and Kage Warrior within the Droid Army of the Confederacy of Independent Systems. Furthermore, he was the sibling of Captain Rackham Sear, who also held a position as an officer in the CIS.
Sear was stationed on the planet of Kardoa as part of the Confederate Droid forces. While there, alongside Generals Grievous and Kleeve, he observed footage from a Recon droid which verified the Republic's presence on Kardoa. Subsequently, Kleeve and Grievous departed, tasking Sear with confronting Jedi General Depa Billaba's clone battalion. Sear then spearheaded the attack, isolating Billaba from both her battalion and her apprentice, Caleb Dume.
However, Sear was compelled to withdraw when Billaba, accompanied by a few troopers, launched an assault on his transport shuttles. Following this, Sear traveled to the planet Mygeeto and joined Grievous in the third battle for that world. Sear, Grievous, and their combined forces subsequently attacked Billaba's base. During this assault, he killed clone trooper Stance within Dume's line of sight. Following this, he engaged Dume in combat, while Grievous confronted Billaba.
Dume then battled Sear to avenge Stance's death. Their duel continued until Dume struck his flamethrower. Sear was then given the opportunity to surrender, which he declined. Unfortunately, Sear accidentally set himself ablaze. He attempted to bring Dume down with him, but died when Caleb used his lightsaber to cut him down.
Like other Kage Warriors, Sear possessed significant skill in wielding an electro sword. He demonstrated his proficiency with this weapon during his fight with Dume. Furthermore, he employed a flamethrower against Dume.