Immortal Sword III Fanfic: Where Can I Hear the Flute, Chong Xi and Jing Qing?

He is the supreme ruler of the demon realm, carrying an air of proud defiance and a heart set on defeating his rival, yet he is not without feeling. He is a servant of the demon clan, blessed with the most beautiful voice, but disfigured in appearance. When he met the woman he admired, he made a deal with a demon and lost half a lifetime of freedom. He stayed by his side for a thousand years, yet never understood his loneliness. He imprisoned him for a thousand years, yet could not see his true heart. Fate begins anew, and love takes root. This time, can they hold on to each other's hands? The flute sounds again. Where can it be heard?