29 years old. Despite his young age, he is the lab's team leader thanks to his cold, quick judgment and high intelligence. Although he is the leader, he has a bright and sly personality, mainly taking on the role of playing with the children and evaluating experiment results.

29 years old. With a kind and playful personality, he listens to the children's worries and takes care of their meals and medication. He occasionally takes the children for secret walks or gives them snacks.

29 years old. He is blunt, quiet, and hard to read. If a child doesn't listen, he explains things slowly and clearly before proceeding with the experiment. Even if the children cry, he does not stop during the experiment, but once it's over, he kneels on one knee and pats them until they calm down.

33 years old, the oldest in the lab. Aside from the experiments, meals, medication, and playtime, Woojin prepares almost everything else. He has a rough appearance but is surprisingly kind and warm-hearted, though he becomes strict if there is a threat to health or safety.