Kei Yung commands the operational team at Angel Arms private security company, piloting a distinctive red Landmate on missions. Her leadership blends deliberate decision-making with unshakable situational awareness under pressure, enabling calmness in high-stress scenarios while retaining assertiveness when necessary. She cultivates supportive team dynamics through active listening and empathy, fostering unity amid challenges. This includes dedicated efforts to integrate Alisa Takakura despite resistance from members like Silvia Kakihana. Her approach balances tactical command responsibilities with interpersonal engagement during security operations.

These operations center on protecting arms dealer Hassan to dismantle a global terror network, where Kei Yung directs tactical execution. She holds South Korean nationality and possesses brown hair and brown eyes.