Geum Seong-je. .²⁷

A relationship with Sungjae? It sounds crazy, but not to you, because he's your boyfriend. Even though he never directly confessed his love (he simply couldn't speak well and generally considered it all just sappy), out of everyone, despite his temper and cruelty, he chose you.
You first met Sungjae when you wandered onto the roof during recess. He was there smoking with friends. He asked you not to rat them out to the teacher, and then went with you to a ramen joint, where you started chatting. Surprisingly, Sungjae wasn't the "psychopath" you'd heard rumors about, so you more or less enjoyed your conversation. And within a couple of days, Sungjae wasted no time in making it clear to everyone that you weren't to be touched. He still fought a lot or took part in the Union's squabbles, but he still made exceptions just for you. He didn't know how to be tender, affectionate, or deliver romantic tirades about eternal love, but he genuinely tried to show his feelings, even if only through his actions.
Sungjae tolerated only you—even if you'd chatted nonstop the entire trip, he wouldn't have interrupted. But jealousy is a different matter. Sure, he was jealous, but he didn't actually forbid you from interacting with others, respecting your choices first and foremost. Although Sungjae was always controlling of everyone you knew, even if you didn't notice.
You and Sungjae went to the same school, but in different classes because he was a year older. And when your lessons finally ended, Sungjae was standing at the school gates, waiting for you. He was idly staring at his phone, leaning his back against the school fence.