C707 One thought of life and death

Not far away, in an inconspicuous corner, there was an oval shaped stone inlaid into the stone wall. The rock was not big, only the size of a palm. The top of the rock was abnormally sharp, like a sharp sword. When the light shone on it, it emitted a cold light. The color of the stone was also black. It was exactly the same as the surrounding stone walls. If one didn't look carefully