Hwang Hyunjin, age twenty-four, is the mafia’s silent blade — unreadable, sharp, and cold enough to freeze a room with a single glance. Under the leadership of Choi San and Wooyoung—two calm, strategic masterminds—the group operates more like a family than a gang. Ryujin, Bambam, Jihyun, and Soohyun complete the circle: strong, capable, and impossibly loyal.

But the quietest presence among them is Kim Seungmin. Nineteen, quiet, unreadable, and lethal when he needs to be. Nobody ever knows what he’s thinking. He moves like smoke, disappears like mist, and lives halfway in Hyunjin’s shadow—by choice.

Seungmin and Hyunjin are close. Too close. Sharing beds when the nights get long, sitting shoulder-to-shoulder during missions, speaking without words. They claim it’s just habit. The others know better.

Seungmin is the mafia’s stealth expert, trained to slip through hallways, rooftops, and enemy safehouses without a sound. To perfect his agility, he practices arch control every day. And every day, Hyunjin stands behind him, one large hand on his lower back, guiding him, grounding him, and forcing Seungmin to hold still until his body learns absolute silence.

Everyone trains together. Everyone sees it. But nobody says a thing.

⸻

The training room hummed with low breaths and soft thuds against mats. San counted rhythmically from the center. “Three… two… one—hold.”

Hyunjin didn’t move from where he stood behind Seungmin, one palm pressed firmly to the small of Seungmin’s back. His cold voice barely left his throat.

“Lean. More.”

Seungmin exhaled, slow and controlled, bending backward into the arch Hyunjin demanded. His hands stayed loosely at his sides, chest rising as he fought to hold the form. The lights above traced the perfect curve of his spine.

Ryujin glanced over between her own sets. “His balance is better than last week.”

San nodded without turning. “He’s stabilizing through his core now. Good.”

Hyunjin didn’t react. His hand simply stayed where it was—steady, unmoving, warm despite his expression. Seungmin’s breath shook for half a second, but he stayed silent as always.

“Don’t fight it,” Hyunjin muttered, fingers pressing just slightly deeper into the curve of Seungmin’s lower back. “Let it pull you.”

Seungmin obeyed, arch deepening. Bambam paused mid-punch against a practice dummy.

“Damn. That’s clean. If he keeps this up, those rooftop scouts won’t hear him at all.”

Jihyun tilted her head. “His shoulders are relaxed too. Hyunjin, good hold.”

Hyunjin said nothing—just adjusted his stance, stepping closer so Seungmin wouldn’t lose balance.

San continued counting. “Five more seconds. Hold… don’t drop.”

Everyone knew this wasn’t teasing. This was precision. Discipline. Family helping family get sharper.

Seungmin’s breathing grew quieter, more controlled. Hyunjin’s hand held him still—calm, instructive, without hesitation. The trust between them was almost louder than the training itself.

Finally, San called, “Release.”

Hyunjin’s hand left Seungmin’s back slowly, allowing Seungmin to rise without strain. Seungmin straightened, breathing softly through his nose. His bangs stuck to his forehead, chest lifting and falling with quiet exhaustion.

“You did well,” Hyunjin murmured.

To anyone else, those three words would’ve meant nothing. But Seungmin’s eyes flickered—just barely—and he nodded once.

Before he could move, Wooyoung clapped his hands. “Alright, baby wolf, sit.”

Seungmin obediently settled onto a low bench. Wooyoung knelt in front of him, pulling out the roll of soft elastic wrap he always kept ready after arch training.

Hyunjin lingered a few steps away, watching.

Wooyoung wrapped Seungmin’s waist with practiced, gentle fingers, the fabric tightening protectively around Seungmin’s lower back and ribs.

“Your skin’s gonna bruise if I don’t do this,” Wooyoung scolded lightly, but his tone was warm. “You bend like paper. Strong paper, but still paper.”

Seungmin stayed silent, staring straight ahead while Wooyoung secured the bandage.

“There.” Wooyoung rose. “All wrapped.”