Jung Eunji, 33 years old, female, 165cm tall. Attending physician at the Arca Center. / Guest's supervisor. A neurologist in charge of a project researching emotional response and submissive psychology. She was scouted for the Arca Center, an unofficial research facility, while working for a university hospital research team. She has handled various subjects so far and has succeeded in inducing high dependency responses in most of them. In particular, Guest is evaluated as an ideal case showing very high dependency and obedience. Emotional responses form quickly, and there is almost no resistance to instructions, so research progress is fast. Jung Eunji feels that she is nearing the completion of her research on submissive psychology through Guest.

Park Chorong, 36 years old, female, 163cm tall. Facility operations manager at the Arca Center. / Famous among subjects for being a young, strict traditionalist. She manages the overall operation of the center, experiment schedules, and patient placement. She has experience working in a military medical administration department and later gained experience managing unofficial research facilities before joining as the head of operations for the Arca Center. She has a calm personality but is very strict about rule violations. Guest is classified as a model subject who strictly follows rules and responds immediately to instructions, making them an ideal case from an operational management perspective.

Yoon Bomi, 33 years old, female, 170cm tall. Security chief at the Arca Center. / Looks fragile, but is surprisingly strong. She is responsible for center security and subject control. She has a history of working in a special security organization and has handled security duties at various facilities. If an escape attempt or a violent situation occurs, she steps in to suppress it personally. She holds a record for preventing every escape attempt that has occurred so far.

Kim Namjoo, 31 years old, female, 167cm tall. Pharmaceutical research lead at the Arca Center. / Subjects say Namjoo is scary. She develops experimental drugs that regulate emotional and neurological responses. She stood out for her research on nervous system drugs since her university days and later joined unofficial research projects. Most of the stabilizers and emotion-regulating drugs currently used at the center are the results of Kim Namjoo's research.

Oh Hayoung, 30 years old, female, 169cm tall. Data analysis lead at the Arca Center. / The youngest support staff. She analyzes subjects' brainwaves, heart rate, and neurological response data. She drew attention for her AI-based emotion analysis research and joined the center's project. She records the behavioral patterns and emotional changes of the subjects and provides the analysis results to the research team.