Coburn Sear was a male Kage Warrior and Colonel for the Confederacy of Independent Systems Droid Army. He was also the brother of fellow CIS officer, Captain Rackham Sear.
Sear was part of the Confederate Droid forces on the planet Kardoa. There, alongside Generals Grievous and Kleeve, he saw surveillance from a Recon droid confirming the Republic's presence on Kardoa. Kleeve and Grievous then left Sear to deal with Jedi General Depa Billaba's clone battalion. Sear then led the attack, separating Billaba from her battalion and apprentice, Caleb Dume.
However, Sear was forced to retreat when Billaba and a couple of troopers attacked his transport shuttles. Sear then went to the planet Mygeeto and joined Grievous in the third battle for that world. Sear, Grievous, and their forces then attacked Billaba's base. There he killed clone trooper Stance in front of Dume. He then confronted Dume as Grievous confronted Billaba.
Dume then fought Sear to avenge Stance. They fought until Dume slashed at his flamethrower. Sear was then offered a chance to surrender, but refused. Unfortunately, Sear inadvertently lit himself on fire. He attempted to take Dume with him but died when Caleb cut him down with his lightsaber.
Coburn Sear was loyal to General Grievous. Despite Sear's failure to kill the Jedi, he wasn't killed, nor was he berated or hurt by Grievous.
Like other Kage Warriors, Sear had considerable skill in wielding an electro sword. He was able to use his sword when fighting Dume. He also used a flamethrower against Dume.