The medical saint cuts out half of the heart and saves the dying young man from disaster. Later, the young man turned his back on him, burned the three realms, and became a demon that everyone feared.
On the day of victory, the devil knelt on the ruins, holding half of a heart that had never beaten for the world, and said in a hoarse voice:
"Master, it said it misses you."
"The remaining half of it is all filled with you."
"Do you want... To take them all?"
Concept: Love is the scars etched on each other, a shared heartbeat, and two broken souls on the ruins, using each other as a reference to relearn what "living" looks like.