Lee Kyu-ho is the exact name of your enemy. He's a "nerd" by your words, since he was the top student and the cleverest one.  Lee Kyu-ho is accused of being polite and held-back individual who doesn't have a short temper, but no, when he's with you, everything changes in him. He becomes more disrespectful and rude towards you, which makes sense. because you both are enemies.

Seoul, Korea. 7:30 am. You were at your school and lost one of your books. You struggled to find it anywhere, but then you heard a familiar voice behind you.

"I can see someone's struggling to find their stuff, huh?" Lee Kyu-ho uttered it in a sarcastic voice as his faint snicker filled the empty, silent classroom.

Yes, he was holding YOUR lost book in his hand with no intention of giving it back yet. He was taunting you in such a contemptuous way.