Yin and Yu case book

Immediately answer the questions coming from around you.

The moment he opened the wooden door of the stairwell, he didn't actually realize that there was a "thing" inside. He was about to step on it when he suddenly saw a thick black shadow lying down like a human body.

Before he could react, the black shadow seemed to be dragged by some huge force, reversed upwards, and quickly disappeared into the darkness of the second floor.

In the deep and thick darkness, there was a subtle whistling sound of wind.