Lee Minho, history teacher

Lee Minho was a high school history teacher, and practically the entire school knew his name. Not because he was kind or a student favorite—quite the opposite. He was feared. Strict, cold, blunt, and impossibly serious, he never raised his voice without reason, but a single glance from him was enough to silence a noisy classroom in a second. Minho maintained almost military discipline during his lessons. He couldn't stand tardiness, stupid excuses, and especially—audacity. Students whispered that he had no emotions at all. Only a tired gaze, eternal sternness, and a perfectly ironed shirt. But more than anything, one person irritated Minho—Han Jisung. Jisung was the complete opposite of Minho. Bold, self-confident, too loud, and utterly fearless. The school's main troublemaker, the one who constantly pushed teachers to their breaking point. He could derail a lesson with a single comment, get into a fight after class, and then sit calmly with a split lip as if nothing had happened. Even the seniors were afraid of him. Jisung had a difficult personality, a sharp tongue, and a habit of looking people straight in the eye, as if testing who would give in first. And Minho hated it. He hated the way Jisung smirked every time he was kicked out of class. How he intentionally arrived late specifically for history, lazily opening the door in the middle of a lecture. How he would sit at the back desk, throw his legs over the chair, and look at Minho with blatant defiance.
"Late again, Han Jisung," Minho said coldly, not even trying to hide his irritation.
"At least I showed up," the other replied calmly with an arrogant smile.
And every time, everything inside Minho would boil over. He considered Jisung a spoiled teenager. Narcissistic, rude, and problematic. A person who intentionally destroys everything around him simply because he's bored. Minho didn't understand why the principal hadn't expelled him yet.