EP06. The Empty Seat

Characters

• Shinwoo Kang (Protagonist) — A scholarship cadet from an orphanage. He maintains a deep romantic relationship with Seoha and naturally frequents her room. Possessing exceptional judgment and physical ability, he is left behind to protect his colleagues on a strange street during an overseas deployment, where he sustains a severe injury. This injury and the resulting memory gap become the decisive catalyst for his eventual transformation into the mercenary ace 'STRAY'. He is blunt but affectionate toward Seoha, a long-time friend and rival to Doyoon, and trusted by Yuri as an outstanding colleague.
• Seoha Yoon — An intern in flight operations and control support. She is in a secret relationship with Shinwoo and has built a deep bond by sharing her apartment with him. When Shinwoo goes silent after being injured abroad, she displays a strong, rational side, tracking the truth by cross-referencing flight records, hospital locations, and return manifests rather than simply grieving. Shinwoo's absence becomes the first step in her growth into an international aviation safety risk expert.
• Doyoon Seo — Shinwoo's roommate and friend. He has feelings for Yuri Han, but feels a subtle sense of alienation and jealousy as he notices her gaze often drifting toward Shinwoo. During an overseas training crisis, he attempts to protect Yuri first but fails to fully control the situation. After Shinwoo is injured, he makes a cowardly choice to avoid the truth and remain silent during the document transfer process involving Kijun Baek's shadow.
• Yuri Han — An excellent cadet with a cold, sharp beauty. She is not merely someone to be protected; she is a skilled individual who catches critical errors during training and acts most rationally in crisis situations. She feels a deep sense of debt toward Shinwoo for staying behind and getting injured in their stead, and becomes a key witness to Doyoon's suspicious behavior and Shinwoo's absence after returning home.
• Harin Min — Seoha's close friend. She is aware of the relationship between Seoha and Shinwoo and acts as an emotional support system when Seoha is left alone after Shinwoo leaves for overseas. She offers realistic advice as Seoha checks hospitals and return flight manifests.
• Taesung Park — A strict instructor at the aviation academy. He selects Shinwoo, Doyoon, and Yuri for the advanced course top team and orders their overseas joint training deployment. A man of principle, he demands high standards from his trainees.
• Local Liaison — The individual in charge of administration and hospital transfers at the overseas training site. While appearing procedural and bureaucratic on the surface, he actually carries out Kijun Baek's orders to spirit Shinwoo away to a different facility.
• Kijun Baek — A dark figure bridging the aviation industry and the world of mercenaries. He does not appear directly in EP06, but is hinted at through signatures on documents or as a recipient of emails. He is the mastermind who recognized Shinwoo's potential and designed the plan to spirit him away under the guise of an accident.
• Local Men — A group of thugs loitering in the back alleys of the overseas training site. They approach Yuri, are stopped by Doyoon and Shinwoo, and later corner Shinwoo in an alley, inflicting a fatal wound.