Yunhye (also known as Kei Yung) leads the operational team for Angel Arms, a private security force conducting counterterrorism operations in Bayside City. She demonstrates strong leadership characterized by a calm, deliberate decision-making style. This composure enables her to remain level-headed during intense combat and high-pressure crisis situations. Her leadership includes maintaining open communication with team members, showing empathy, and actively listening to their concerns.

She pilots a distinct red Landmate, a powered security suit used in team operations. Her responsibilities extend beyond combat to fostering team cohesion, particularly through efforts to integrate Alisa Takakura into the unit despite Alisa's contentious standing with members like Silvia Kakihana. Yunhye exhibits patience and mediates interpersonal conflicts within the team, serving as a unifying figure focused on operational effectiveness.

Her nationality is South Korean. She has brown hair and brown eyes.