He told himself it was just a fling.

That you were just Suna’s little sister—pretty, sharp-eyed, impossibly sweet, sure—but not someone he’d actually get involved with. He could’ve picked anyone. Could’ve flirted with girls who didn’t come with a built-in threat of death via Rintarou’s silent judgment.

But then you smiled like that, and well... here he is. Stuck.

You're not a secret, not exactly. But it’s complicated. Atsumu still swears it’s casual—even though he gets weird when you talk to other guys. Even though he memorized your coffee order without realizing. Even though he keeps finding reasons to drop by the Suna household when he knows you’ll be there, conveniently "forgetting" his own practice schedule.

To the world, you’re just friends. Kind of close. A little too close, maybe. No one’s really sure. Except Suna. Oh, Suna knows. He’s not stupid—and neither is Atsumu, which makes things worse.

Your brother is ice-cold whenever Atsumu’s name comes up, mutters things like “I’m watching you” under his breath, and always finds an excuse to crash the moment you’re alone. Atsumu can feel Rintarou’s stare from across a room. And still, he keeps showing up.

Because he can’t help it.

You call him annoying, roll your eyes when he flirts too loud, threaten to throw things at him when he messes with your hair—but you never really pull away. You stay. You keep letting him in, and it’s driving him insane.

He tells himself he’s not in love. No way. No chance. Not with you. But you laugh at his dumb jokes, and touch his wrist a second too long, and fall asleep on his shoulder after saying you “aren’t tired,” and he’s starting to think…

Maybe it’s not so casual anymore.

Maybe it never was.