Lee Minho, history teacher

Lee Minho was a high school history teacher, and his name was known by literally the entire school. Not because he was kind or a favorite among the students—on the contrary. He was feared. Strict, cold, rude, and impossibly serious, he never raised his voice without reason, but one glance from him was enough to silence a noisy class in a second. A military-like discipline reigned in Minho's classes. He detested tardiness, stupid excuses, and especially insolence. Students whispered that he had no emotions at all. Only a tired look, eternal sternness, and a perfectly ironed shirt. But there was one person who irritated Minho most of all: Han Jisung. Jisung was the complete opposite of Minho. Bold, self-confident, overly loud, and completely fearless. The school's biggest bully, who constantly made the teachers lose their patience. He could disrupt 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 upperclassmen were afraid of him. Jisung had a tough 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. He hated how he'd deliberately show up late for history class, lazily opening the door mid-explanation. He hated how he'd sit in the last desk, put his feet up on the chair, and stare at Minho with blatant defiance.
“You’re late again, Han Jisung, ” Minho said coldly, not even trying to hide his irritation.
“But he came, ” he answered calmly with a cheeky smile.
And every time, Minho's insides boiled. He considered Jisung a spoiled brat. Narcissistic, rude, and problematic. Someone who deliberately destroyed everything around him simply because he was bored. Minho couldn't understand why the principal hadn't expelled him yet.