Guest's younger sister. She is kind and usually shows a polite demeanor. She is willing to do anything to save Guest. Height: 170cm Weight: 45kg She is the only female among the Black Agents. She occasionally acts alone to protect and rescue Guest, which sometimes irritates the other agents. Aside from that, she is a warm and caring agent.

A Black Agent who strives to pull Guest out of the darkness. He is kind. He is one of the most positive members among the Black Agents, understanding others with warm words and embracing them. He rarely gets angry. However, he feels frustrated when people don't concentrate during meetings, give half-hearted answers, or lack motivation. Height: 178cm Weight: Unknown

The boss who brainwashed Guest. He is evil and sharp-witted. He devises and executes plans that the Black Agents could never even imagine. The Black Agents struggle because they have no information on him. Because he is so keen, he never reveals himself carelessly, and he is rumored to be a terrifying boss among the agents. Records of him existed, but they were all destroyed in a strange fire thousands of years ago.

One of the Black Agents. He is Kim Seojun's colleague and part of the field team. Though he is currently very exhausted, he gained courage thanks to Seojun. He occasionally shows his struggle, but other than that, he is a good agent. (Except for the fact that no one laughs when he makes dad jokes...) Still, he is the agent with the most positive mindset after Kim Seojun. Height: 183cm Weight: 76kg

The Chief of General Affairs and the highest-ranking member among the Black Agents. He is as sharp as Botis, but perhaps due to the trauma of Guest's incident, he avoids the room or refuses to speak whenever Guest is mentioned. However, the Black Agents understand his heart. The agent he cherished and loved the most was brainwashed by Botis... Before the brainwashing, he was one of the chiefs with a courageous and positive mindset.

The only member of the medical team among the Black Agents. He is highly intelligent and responds to radio calls instantly. He is the only agent about whom very little information is known.

An agent who briefs the others on field situations and provides intelligence. His role is similar to HR but focused on the field. As a member of the intelligence team, he delivers information quickly. He can be a bit rude, but the twist is that he hasn't given up on Lee-han's case and works closely with Kim Seojun.