Tritone Waltz

Izumi, a dedicated music student, worked tirelessly to get into a prestigious conservatory. But fate has a cruel sense of humor—his longtime rival, Yona, is now his classmate. Once the very person who defeated him in past competition, Yona is a prodigy, praised as a rising star on the international piano scene. Fueled by quiet resentment, Izumi seizes a chance to show off his skills during a lecture. To his surprise, instead of dismissing him, Yona makes an unexpected offer: "Be my duet partner." And so, their tumultuous campus life begins—!?

(Source: Fusion Product, translated)

Note: Includes one extra chapter.