They always said the same things about him.
Too quiet.
Too slow.
Too weak.
Kairo learned this before he learned how to fight, before he learned how to dream. The words followed him through the village like shadows that refused to leave. When the other boys trained with wooden swords, laughing as they swung too hard and missed, Kairo stood at the edge of the yard, holding his own blade as if it weighed more than it should.
"Don't strain yourself," someone would say.
"He's not built for this," another would laugh.
At first, Kairo argued inside his head. They're wrong.
Later, he stopped arguing. If everyone said he was weak, then maybe weakness was simply his truth.
Even his reflection seemed to agree.
Thin arms. Careful eyes. A posture shaped by apology.
Only one person ever spoke differently—his grandfather.
Old Master Raizen lived at the edge of the village, where the wind bent the trees and the air felt heavier, older. People avoided the place, whispering that something about the old man made their skin crawl. They said his gaze lingered too long, as if he were remembering things no human should know.
But to Kairo, Raizen was warmth.
"You're listening too hard to voices that don't matter," his grandfather once said, stirring tea that smelled of ash and herbs. "Strength isn't always loud."
Kairo wanted to believe him. He really did.
Still, when Raizen's health began to fail, the village barely noticed. And when the old man finally died, the sky did not darken. No thunder fell. Life moved on, as if nothing important had been lost.
Except for one thing.
On the night of Raizen's funeral, Kairo woke with fire in his veins.
The air in the room twisted, shadows stretching unnaturally across the walls. His chest burned—not pain, not exactly—but pressure, like something vast trying to breathe inside a body too small to hold it.
"Kairo," a voice echoed, deep and ancient, yet unmistakably familiar.
He fell to his knees.
From the darkness, the shape of his grandfather appeared—not old, not weak, but towering, crowned in horns of shadow and flame. His eyes burned crimson, carrying centuries of command and destruction.
"I was not only your grandfather," the figure said.
"I was the Demon King."
Kairo's world shattered in silence.
"I have ruled, destroyed, and been feared," Raizen continued. "And now, I am dead. My enemies would erase my bloodline if they knew the truth."
The pressure in Kairo's chest intensified.
"So I sealed my power inside you."
The shadows surged and sank into Kairo's body like chains of light and darkness.
"You will be underestimated," the Demon King said softly. "You will be called weak. Let them believe it."
The vision faded. The fire cooled.
Kairo collapsed, trembling.
Outside, the world looked the same. The village slept peacefully. No one knew that the weakest boy among them now carried the sealed power of a Demon King.
And deep within his soul, a promise echoed—one his grandfather had whispered long ago, half-joking, half-serious:
One day, you will become a Demon King.
This time, it was no joke.