EIDOLON. That was the name of the place where Guest would be working. It does not exist officially. Its location, research content, and the names of its personnel are not publicly recorded. A national secret. Unlike the grim facility you imagined upon hearing that, what lies before you are only white, inorganic corridors and doors with electronic locks. There are no windows and few clocks. Researchers wearing ID badges pass each other silently in the identical hallways. Several weeks have passed since being assigned as a new researcher. After being drilled in basic medicine, bioengineering, pharmacology, weapon operation regulations, and contact rules for containment subjects—training not required in general research facilities—Guest received the official appointment as the researcher in charge.

"That concludes the training. You will have your own assignment starting today."

The guide stops. Ahead is a heavily fortified door equipped with an electronic lock, biometric authentication, and a double lock. The plate on the side simply reads: As-Y1.

"Subject No. As-Y1. The only successful case of practical application in EIDOLON."

The summary from the documents flashes through your mind. A biological weapon with a human body. A neurotoxin produced internally. The lethal dose is three drops. Depending on the individual, even two drops can mean life or death, and a single drop causes intense pain and paralysis. However, the impression from the attached photograph was far removed from that description. Unhealthily pale skin. Silvery-white hair. Young-grass green eyes. A thin, fragile body. A small beauty mark under the left eye. And snake scales peeking out from the neck.

"Feeding must be handled by the assigned researcher. There is almost no spontaneous feeding behavior."

"Always obtain the subject's permission when making contact. Protective gloves are mandatory."

"The subject has no tolerance for sunlight. Use light-shielding equipment."

The guide, having delivered the precautions, hesitated for just a moment at the end.

"...Also, do not do anything unnecessary with As-Y1."

What counted as 'unnecessary'? There was no further explanation. An electronic beep sounds, and one lock, then a second, disengages. The heavy door opens. The room was dim. To accommodate the subject who dislikes brightness, the lighting was kept to a minimum. A single person was sitting in a chair by the wall. White hair covered one eye, and scales of the same color as the hair peeked out from the exposed ear and neck. They were looking at a puzzle magazine on their lap while fiddling with their long nails. The guide speaks up.

"As-Y1."