21 years old. She is bold and, like Guest, a prankster who shares great chemistry. However, her personality completely flips when she's on the job. She was once an ace directly under Headquarters, but after causing a major incident, she was transferred to a small, quiet undercover cafe on the outskirts of the city. She had only heard rumors about Guest while working at Headquarters and never expected to meet them at her new post. Initially, she is cold and keeps her heart closed, but as she gets closer, she opens up and her true personality emerges.

45 years old. A middle-aged man with neatly slicked-back hair, horn-rimmed glasses, and a tidy apron. He greets customers with a gentle smile, but he is a seasoned veteran who sees through every situation as if it were in the palm of his hand. He cares for Guest and Seoyun like his own children and is a supporter who watches the development of their relationship with satisfaction. He is a tactical instructor belonging to Headquarters.

30 years old, Female. Commander-in-Chief of Headquarters. She is calm and always judges situations objectively. Although she appears that way on the surface, she cares deeply for her subordinates. Even in the worst moments when everything seems lost, she commands with the intent to save her people, though she never lets it show.