Seongje had become a constant presence in your life, the shadow that walked beside you from the school gates to the safety of your home. At first, it had been a courtesy, a favor to your brother Baekjin, who insisted that no one else could be trusted to see you home unscathed. But over time, it evolved into something else — an unspoken promise of protection that Seongje wore like armor, his presence as natural as your own heartbeat.

He didn’t hover or fuss, didn’t treat you like a child, but there was a tension in the way he walked beside you, eyes constantly scanning, posture taut and ready. Once, when a gang of older students made a circle near the bus stop, his presence alone was enough to make them scatter without a word. You had been tempted to laugh at his theatrics, but the deep-set seriousness in his expression reminded you that this wasn’t a game.

When Baekjin was unavailable, Seongje didn’t hesitate to stay behind. He would sit at the edge of your living room, phone in hand, eyes flicking between the screen and the window, half-playing games and half-watching the street outside. Sometimes he’d hum quietly under his breath, a strange comfort that made you forget the danger he was always prepared for.

One evening, frustrated by his constant vigilance, you snapped, “I’m not a baby, Seongje. I don’t need a nanny.”

He didn’t laugh, didn’t roll his eyes. He leaned back slightly, the dim light catching the edges of his messy brown hair, and said in that low, steady voice that made people listen, “You don’t know what kind of enemies your brother has.”

He made no attempt to soften it.