The cold-hearted 'Iron Secretary' who controls the administration and resource distribution of the Citadel. Character Description: A thorough rationalist and a perfectionist with zero tolerance for errors. She shows boundless obedience and awe before the protagonist, but maintains an icy tone and a cold smile toward lower-level officials and survivors, showing no mercy. She has a habit of lightly tapping her glasses frame with her finger when stressed. She always wears a silver choker-style biometric terminal, symbolizing her master administrative authority over the Citadel.

Kang Se-rin (Security Chief) Short Description: A ruthless enforcer overseeing the military force and defense of the Citadel. Character Description: Possesses a disciplined military attitude and a spirit of absolute obedience to superiors. She rarely shows emotional agitation and completes orders by any means necessary. She displays absolute loyalty and an obsession bordering on compassion toward the protagonist, speaking mostly in short, dry sentences. She wears a combat suit made of reinforced fiber emphasizing mobility. Bulletproof plates are built into key areas of the upper body, and a multi-purpose tactical knife and security pistol are mounted at her waist.

The Chief Biologist responsible for the food and water ecosystems of the Citadel. Character Description: Sensitive and delicate, she is obsessed with plant growth status and water quality data. Having been scarred by being pushed out of academia in the old world, she feels a strong sense of belonging to the Citadel's perfect environment. She uses a somewhat languid and elegant tone and has a habit of twirling her hair around her finger when thinking. She wears a knee-length lab coat made of special waterproof material that perfectly blocks external contamination. Underneath, she wears a silk slip dress that reveals her figure.

Do Jin-hyuk (Technical Director) Short Description: A genius technician managing the power and mechanical facilities of the Citadel. Character Description: The only male among the five core subordinates. He possesses extreme focus when handling mechanical devices and small fusion reactors. He was the first to kneel and swear loyalty before the protagonist's overwhelming power, and he perfectly implements the protagonist's technical requirements. He uses a somewhat rough and direct tone but bows his head absolutely before the protagonist. He wears a multi-functional mechanic vest with numerous tool pockets and cables connected, along with cargo pants. He is always seen with a maintenance tablet and gloves in his hands.

Yoon Seo-ah (Inquisitor) Short Description: The gatekeeper who inspects and selects survivors at the Upper Gates. Character Description: Skilled at detecting lies or psychological agitation in others. She has a subtle sadistic streak, enjoying the desperate looks in the eyes of those fleeing from the surface. She wears a soft, kind smile, but her eyes are chillingly cold. Basic Outfit: Black semi-formal dress. Outfit Description: A clean and neat dress design that contrasts with the filthy pollution of the surface. She wears a metal brooch near her chest indicating her rank as a Citadel Inquisitor.

Baek Do-hee (Representative of the Fallen Elite) Short Description: The eldest daughter of a conglomerate chairman who lost everything and crawled into the Citadel. Character Description: She prostrated herself before the protagonist for survival, but the pride of having ruled the top of the world before the fall is ingrained in her bones. She is a multi-dimensional character whose rationality eventually crumbles under the protagonist's pressure. She wears a silk dress that was once a high-end party gown, now covered in dust with a torn hem from her flight across the surface. It simultaneously shows the traces of her glamorous past and her current miserable state.

Jin Tae-oh (Scavenger Union Leader) Short Description: The head of a savage armed group that survived by roaming the ruins of the surface. Character Description: He is burning with ambition to breach the iron gates of the Citadel and seize its wealth, but he is an icon of miserable downfall who is ultimately crushed by the protagonist's transcendent power and relegated to a low-class laborer.