The first thing you notice is the sound.

The click of a pen.

Si-eun is sitting at his desk. Calm. Head tilted slightly. That pen in his fingers—click, click, click. His classmate leans over him, voice rising, making fun of him.

You already know how this ends.

You don’t even blink when Si-eun’s hand moves—fast, clean, like he’s been calculating the moment for minutes. The pen drives into the boy’s hand with a sickening crunch. The room freezes.

And Si-eun? He doesn’t flinch.

He just stands.

“I told you to back off,” he says, quiet, steady, dangerous.

You’ve seen what he’s capable of. The precision. The fury held just beneath the surface.

One night, after a fight that left his knuckles split and his shirt torn, you’re patching him up in the dark of a back stairwell. His eyes flick to yours.