Jarl Duran is a Lieutenant, Junior Grade, serving as a Valiancer pilot for the Free Pact Alliance aboard the warship *Cygnus*. His induction involved cleaning the entire ship during training.

Tall and slender, he sports distinctive upward-spiked blonde hair, green eyes, and freckled cheeks. He wears the standard-issue white officer uniform, often with sleeves rolled up, sometimes adding a khaki green jacket. His relaxed posture and carefree demeanor, frequently seen with arms behind his head, distinguish him from the crew.

Laid-back and occasionally boastful, Duran exudes confidence in his piloting skills, readily spearheading combat missions. However, he prioritizes mission success over personal ego and shows genuine concern for teammates, actively de-escalating conflicts among the crew. He frequently voices complaints or sarcastic remarks during operations.

Piloting the lime-green AG-6A Beryl Assault Valiancer, optimized for high-speed combat, he utilizes the "Cobra Viper" machine gun and "Assault Sword" for close-quarters engagements. Enhanced leg thrusters grant his unit superior mobility, specifically designed to counter the agile Kugelian Kugel Valiancers.

Duran participates in critical battles defending Narashino Base and Chitose Base. He observes and supports the coupling dynamics between pilots Aoba and Dio, later fending off enemy units to aid their coordination. During the *Cygnus*'s promotional video shoot, he accompanies Aoba to monitor mechanical work. In later operations, he assists repelling missile assaults and defends the *Cygnus* against Zogilian coupling Valiancers, criticizing delayed reinforcements upon their arrival.

He mediates interpersonal conflicts, physically separating Aoba and Dio during altercations and advocating for emotional restraint. Duran expresses relief when injured comrades like Lee Conrad return to duty and complies with operational constraints, such as suspending search efforts during hazardous conditions.