In a world where demons blend seamlessly into society, marked only by glowing, jagged lines that appear when their power surges—Seoul becomes the secret battlefield. The demon group, known as the “Hellborne,” consists of four ancient and powerful demons: San, Wooyoung, Yugsoo, and Hyunjin. They hide in plain sight, only revealing their true forms when emotions ignite—rage, lust, pain… or love.

Opposing them is the “Celestials,” a group of gifted demon hunters whose voices are weapons of light. Seungmin, the leader, possesses the most heavenly voice, able to paralyze demons with a single note. Alongside him stands Sunoo, Ryujin, and Jihyun—each trained in vocal exorcism and divine harmonics.

Tension simmers between Seungmin and Hyunjin. They’re enemies by title, but something lingers beneath the surface—familiarity, heat, and a bitter kind of longing. Hyunjin constantly teases Seungmin, denying his demon nature just to rile him up. But Seungmin sees through him—especially when the marks start glowing.

Tonight, the truth will burn beneath Seoul’s neon sky.

⸻

Midnight blanketed Seoul like a velvet sheet, the streets eerily silent—too silent. Not even the usual hum of electricity or flicker of headlights disturbed the emptiness. Somewhere between Gangnam’s alleys and the edge of Itaewon, two groups stood across from one another under the cold gaze of a flickering streetlamp.

San stood tall, his presence impossible to ignore, with Wooyoung resting beside him like a wicked shadow. Yugsoo cracked his knuckles, his demon marks faintly pulsing beneath his sleeves. Hyunjin stood slightly ahead, cocky smirk painted on his lips, black coat loose over his bare chest. His veins glimmered faintly under the light—but only just.

Across from them stood the Celestials—Seungmin in the center, shoulders squared, his voice box humming faintly with restrained power. His white shirt clung to his frame, the ends of his coat flowing with each breeze. Sunoo, Ryujin, and Jihyun stood in a semi-circle behind him, all calm… all watching.

“Still pretending, huh?” Seungmin’s voice cut through the tension like silk over a blade.

Hyunjin blinked lazily. “Pretending what?”

“That you’re not a demon.”

“I’m not.”

“You are.” Seungmin’s eyes glinted with knowing. “Just admit it. You want me to say it for you?”

Hyunjin smirked, stepping forward, chest rising with every slow breath. “What if I like hearing you say it?”

Without another word, Seungmin raised a small purple crystal the size of a coin. A light burst out, casting ultraviolet streaks across Hyunjin’s torso.

The laughter stopped.

Bright, jagged demon marks danced across Hyunjin’s skin—crackling like lightning frozen in place. They glowed fiercely against his neck, down his collarbone, even across his ribcage. The sight was raw. Power. Beauty. Sin.

Hyunjin looked down at himself briefly and chuckled darkly. “Damn… busted.”