Euijoo could not figure out what it was, but he always felt something around his older brother's best friend. Things change when years later they end up in the same college. --age gap trope

Two names. Two families. One unshakable rivalry. Lee Leo had been raised to win-every move, every word, every breath crafted to carry the weight of his family's empire. Cold, composed, untouchable-he was the heir everyone feared and respected. Lee Sangwon was the opposite-wild, sharp-tongued, and unafraid to challenge the world. He was the storm that threatened to ruin the perfect order Leo lived by. For years, their hatred burned like a silent war, each encounter another battle in an endless feud. But when an unexpected business merger binds their families, the two heirs find themselves chained together by duty. What begins as venom in their words and fire in their glares soon turns into something neither of them can control. Desire. Longing. The kind of love that could destroy them-or set them free. Because in a world where bloodlines dictate destiny, Leo and Sangwon must decide if they'll remain enemies... or rewrite their legacy together.

Nicholas and Euijoo have been best friends since they were 10. However a few days after Euijoo's 15th birthday, he ends up in a fight with Nicholas which causes him life time damage. - inspired by high school frenemy

The wrong way to love you

"Euijoo meet your brother to be" Junseok tells his son. "Nicholas" Nicholas stares at him in pure horror. He couldn't believe this. What were the odds of this happening? . . . Inspired by the Taiwanese BL The Only One

Nicholas and Maki are known to be the aces of Class 12-B. Everyone knows they excel academically and no one has ever come close to their ranking. They are an intimidating pair who bully other students as sake of entertainment. But when transfer student Byun Euijoo from Busan suddenly becomes part of their class in the middle of the semester, Nicholas feels threatened. Euijoo doesn't just have good grades but is tall and handsome too. Hence he becomes the new target for bullying. However things start to go south, when Class President Fuma and Euijoo start going out and Nicholas can't figure out why it bothers him so much.

Ff about taesan and sungho ship from boynextdoor (The underrated ship) Let's see how they end up together.

euijoo finds out his best friend has a crush and is upset that all their close friends know except him-and perhaps upset over 𝘴𝘰𝘮𝘦𝘵𝘩𝘪𝘯𝘨 𝘦𝘭𝘴𝘦. ao3 version: https://archiveofourown.org/works/44259715/chapters/111302392