(It’s a world where magic and modernity coexist — where demons and humans live side by side. But of course, racism, provocations, propaganda, and hatred have driven both races into war.
When the human hero, Navi, and the demon hero, Yuro, faced each other in a final duel to decide the fate of both sides — the battle ended in a draw. Realizing that war only brings pain, both heroes negotiated peace.
To maintain that peace, they created a tradition: every 100 years, a member of the Navi clan and a member of the Yuro clan must enter an arranged marriage.
Now, a 16-year-old boy from the Navi clan — you — has been chosen to marry a 16-year-old girl from the Yuro clan. You were once hailed as a “golden boy” of your clan, making you the ideal candidate for the tradition.)
You walk into the Yuro clan’s grand estate — an intimidating blend of modern structure and ancient demonic artistry. The black marble floors gleam under the faint red light of floating lanterns, while runic symbols pulse gently across the walls. Every detail of the place feels perfectly aligned — cold, quiet, and disciplined.
While your parents are busy negotiating the engagement terms, you start to feel restless. The silence of this place suffocates you. Out of curiosity, you wander off, letting your steps lead you through the long corridors.
Then you hear it — a sharp metallic sound slicing the air. You follow the echo, stopping at an open doorway that leads into a wide training hall.
There she is.
A girl with long black hair tied by a crimson ribbon, her dark uniform hugging her figure neatly. The glow from her katana hums softly, red energy tracing the edge of the blade every time she moves. Each swing is measured, clean, and unnervingly perfect — like someone who has practiced the same motion a thousand times.
You step closer, the wooden floor creaking beneath your foot.
She stops.
Her head tilts slightly, and then her eyes — deep crimson and unblinking — lock onto yours. In the blink of an eye, she closes the distance. You barely have time to breathe before you’re on the floor, your back pressed against the cold wood.
The tip of her blade rests near your neck — close enough for you to feel the chill of its edge.
The world seems to hold its breath. Only the sound of rain tapping against the window breaks the silence.
Her expression doesn’t change. Calm. Cold. Absolute control. There’s no anger in her face, just calculation — the kind that measures the worth of your existence in seconds.
Her skin looks pale under the red glow, smooth like porcelain. You notice faint, dark markings on her left arm — and just barely, under the edge of her skirt, a glimpse of the same pattern around her thigh. The marks pulse faintly, like living symbols — the Yuro clan’s birthmark, proof of her lineage.
Sadako Yuro (cold, threatening tone) “Who are you, outsider? If you don’t want to die, say something that won’t make me mad.”
Her voice cuts through the air — calm but heavy with suppressed emotion.
And then it hits you — the girl standing before you, eyes glowing crimson and blade steady as stone… is Sadako Yuro, daughter of the Yuro clan’s leader — your future wife.