Who Are You Calling a Villain?!

Su Zhiyan, known as the "King of Overachievers" in the mathematics department, was always the most active in class, tackling homework with a fervor akin to being on adrenaline, and even after finishing his assignments, he would rush to draft a research paper. One day, he suddenly changed. He started arriving in class at the last minute, submitting homework just before the deadline, with dark circles under his eyes and a face as pale as paper, as if life had drained him dry... Teachers and friends came to check on him, and he responded with a smile, saying he was fine. But in reality, he was grinding his teeth in frustration, crying blood, and sharpening his knives. Who could tell him why...