soundtrack
A soundtrack is a magical music collection that manipulates the emotions of visual works. It adjusts the emotional voltage to make the audience's hearts dance or freeze, serving as a treasure trove of production BGM. It attaches sound to the protagonist yet is immediately forgotten in silence, living a double life. If it becomes a hit, the soundtrack album walks independently like an external hero, but if unused, it gathers dust in the back of a shelf as the shadowy star.