In 3640 BBY, during the Galactic War between the Galactic Republic and the resurgent Sith Empire, Yennir of the Green served as a soldier in the Republic Army. Yennir was assigned to Sergeant Shanra Immel's squad and fought alongside SpecForce Colonel Jace Malcom in a battle on Kalandis Seven, a desolate Inner Rim planet covered in fog. During the battle, Yennir and the squad were tasked with the destruction of the local Imperial-controlled spaceport. On the way to their target, the group of soldiers was attacked, and Corporal Amden vor Keioidian was fatally wounded. Immel activated Keioidian's med tracer before ordering the squad to move out and leave Keioidian behind.
Three hours later, the squad finally reached their objective and started planting targeting beacons, which would allow Republic starfighters to destroy the spaceport regardless of the fog. Shortly after Yennir and the squad planted the last of the beacons, the fighters destroyed the spaceport with a bombing run. Malcolm was recalled by the Supreme Chancellor and advised the ship's captain, a Jedi Knight, that the forces on Kalandis Seven would not last long without support. As the ship left the planet, Malcolm looked over a datapad containing the names of the Immel's squad, including Yennir of the Green, and reflected on how he had tried to save them. He then deleted the names from the datapad, preparing to focus on the next engagement against the Sith.
Yennir was hand-chosen by Malcolm for their proficiency, skill, and bravery to complete the mission.
Yennir of the Green appeared, albeit via voice only, in Alexander Freed's short story "The Last Battle of Colonel Jace Malcom," which was published within the 137th issue of the Star Wars Insider magazine on October 23, 2012.