The Life Lamp, a magic artifact capable of sensing the condition of its master.
By entrusting a trace of one's detached Soul Consciousness and igniting the wick, one could determine safety or danger based on the strength of the flame.
If the flame were to extinguish, it would mean that this thread of Soul Consciousness had been extinguished, signifying the fall of the person to whom the Soul Consciousness belongs.
This is the fundamental effect of the Life Lamp.
Extremely convenient, but equally dangerous.
Because this trace of Soul Consciousness was not only useful in confirming life or death, but could also be used as a catalyst for curses. Since the Soul Consciousness and the Divine Soul of the body were one and the same, such curses were almost irresistible, only to be endured with gritted teeth.
This is why Life Lamps were so rare; only those who could entrust each other with life and death would exchange Life Lamps.