Clenna, previously a sergeant in the Imperial forces, transitioned to become a drill sergeant at the Galactic Outdoor Survival School.
Growing up on the industrialized planet of Yalln, young Clenna explored uncharted territories alongside his companion, a tal.
Driven by a desire to become a drill instructor, he later enlisted in the Imperial Army. Despite never achieving his desired position, he gained substantial knowledge, particularly in theoretical aspects. While he resisted the Imperial indoctrination, he harbored animosity towards the Rebel Alliance.
During his time at Ruac Outpost, Clenna encountered and collaborated with Derembus Sitnalta.
Finding himself too old for the Empire, he went back to Yalln, but soon became dissatisfied.
Seeking a change, he enrolled at the Galactic Outdoor Survival School, hoping to "boss around eager trainees". There, under the tutelage of GOSS dean Barosa Warren, Clenna's abilities were honed.
Because of his devotion to Warren, and Warren's conflict with some Rebel officers, the Rebel Alliance saw Clenna as a potential danger. Sitnalta, his former colleague and by 2 ABY a Rebel soldier, submitted a report on Clenna, noting that while age had affected him, he remained a threat due to his access to resources at GOSS.