In the beginning, the world was divided into many kingdoms, each ruled by a different race.
The Clover Kingdom of Elves, the Dwarven Kingdom, the Human Kingdom, the Beastfolk Tribes, the Fairy Dominion, and even the mysterious realm of the Dark Creatures—all races lived in a fragile balance of peace.
Seeking to strengthen that peace, the rulers of every kingdom gathered for a historic summit. Their goal was simple: to unite the nations and allow free travel between their lands.
But one king stood against them.
The Dark King, ruler of the creatures of the abyss, rejected the proposal. Blinded by ambition, he proclaimed that his kingdom was superior to all others. He declared that the world should bow before him…and that he alone would rule as absolute tyrant.
The other kings refused.
And so the Great War began.
The Dark King's forces were overwhelmingly powerful, pushing the united armies to the brink of defeat. Just when all hope seemed lost, the Goddess of Life intervened. She summoned a hero from another world, a warrior bearing power beyond mortal limits.
Together with the allied kingdoms, the hero confronted the Dark King.
Their battle shook the world itself.
In the end, the Dark King was sealed away, his armies scattered across the lands. Though remnants of his forces still attack the kingdoms to this day, humanity and its allies have grown strong enough to keep them at bay.
Yet legends whisper the truth:
The Dark King still lives.
Behind the veil of the seal, he searches relentlessly for a way to break free…
The voice narrating the tale turns out not to be a mysterious storyteller, but a woman sitting at the edge of a small bed.
Melda smiled warmly as she closed the storybook, four children gathered around her.
Her daughters—Elsa, the responsible seven-year-old; Anna, the playful five-year-old; and Bliss, the strangely quiet three-year-old—listened with wide eyes.
In her arms lay Arthur, only a week old.
"So," Melda finished with a teasing grin, "if you're good boys and girls, the Dark King won't come to eat you…"
She wiggled her fingers dramatically.
Inside Melda's arms, baby Arthur narrowed his eyes.
Really? My father doesn't eat children, you wrinkly old hag! the newborn screamed internally.
Of course, on the outside, all that came out was a harmless baby coo.
And even if he DID eat children… being good or bad wouldn't save you.
He smirked to himself.
"Mommmm," Elsa complained, pouting, "why can't Arthur sleep with us tonight? He's our brother!"
"He won't be able to sleep with the way you snore," Anna teased, giggling.
"Grrrrrr! At least I don't talk in my sleep!" Elsa shot back.
"You—!!"
The girls immediately fell into an adorable argument. Melda could only laugh. They were noisy, but cute.
"All right, all right," she said gently. "It's getting late. Time for bed."
"Awwww…" Anna groaned dramatically.
Bliss, as always, said nothing—standing quietly with that cold, gloomy expression no one understood from a three-year-old.
Melda lifted Arthur higher in her arms, gave each girl a goodnight kiss, tucked them in, turned off the lights, and stepped out quietly with the newborn.
Melda carried Arthur down the quiet hallway, the soft glow of lanterns lighting her steps. The house had finally fallen silent—no more bickering from Elsa and Anna, no more tiny footsteps. Only the faint hum of night insects filled the air.
She pushed open the door to the nursery.
The room was gentle and warm, decorated with pastel fabrics and small wooden toys carved by the village craftsmen. A faint breeze drifted through the window, rustling the curtains like a lullaby of its own.
Melda leaned over the small cradle and laid Arthur down with the tenderness of someone handling a miracle.
She brushed a thumb across his tiny cheek.
"Stop touching me, woman!!" Arthur screamed internally, scrunching his face in annoyance.
Outwardly?
He only let out a soft baby murmur.
Melda giggled softly.
"You have so much potential… I can already tell you'll grow up to be a fine man," she whispered, smiling with pure, innocent affection.
Arthur stared up at her, blinking.
You can tell already? Of course you can. I am the Dark King's son. The heir to all darkness. I don't expect anything less.
He puffed his chest proudly—well, as proudly as a week-old baby could.
But then—
"You are the great hero's son, after all," Melda said warmly.
Arthur froze.
His smile shattered.
His pupils shrank.
His heart nearly stopped beating.
…HUHHH!? Who's son??
The air around him felt heavier, colder.
The hero's… son? ME? How—!? The son of the man who sealed away my true father!?
A storm of confusion and fury swirled inside his tiny body. But after a moment…
A slow grin crept across his face.
This… this might actually be perfect. If I grow up as the hero's son… no one will ever suspect me. I can destroy him from the inside. I can erase the kingdom from the roots.
He let out a quiet baby giggle—though in his mind, it was the cackle of a future tyrant.
Melda leaned closer, completely unaware of the evil scheming happening in her baby's head.
"Oh dear, you don't seem tired at all," she said with a playful sigh. "Well… then I'll sing you a lullaby."
She took a breath.
And then she began to sing.
Her voice was soft, gentle—like warm sunlight drifting through leaves. It wrapped around Arthur like a warm blanket, flowing into his ears like silk. It was nothing like the "horrid voice" he expected from a human.
D-Don't try to make me sleep with that disgusting voice—! I won't… I refuse… shut up, woman!
He protested furiously in his mind.
But his eyelids betrayed him.
They began to droop.
The softness of her voice tugged at something deep inside him—something he didn't even know he had. As if someone had taken all the chaos and hatred buried in his heart and wrapped it gently in light.
His tiny fists loosened.
His breathing steadied.
The darkness inside him faded into a drowsy haze.
I'm… not… going to… sleep… he insisted weakly.
But his eyes slowly closed.
Melda watched with a tender smile as his breathing deepened.
She leaned down and pressed a soft kiss to his forehead.
"Good night… my son," she whispered.
The words drifted into Arthur's dreams like a warm spell.
And for the first time in his short life…
the heir to the Dark King fell asleep in peace.
The door clicked softly behind Melda as she left, her footsteps fading down the hall.
For a moment, the nursery was silent.
Then—
Arthur's eyes snapped open, glowing faintly with a sinister purple gleam.
He slowly sat up, then swung his chubby legs over the edge of the crib. With surprising agility for someone who couldn't even walk, he crawled down the wooden bars and landed on the floor with a soft thump.
He dusted off his tiny pajamas—mostly for dramatic effect.
You may be wondering, he said inwardly, pacing across the room like a villain mid-monologue, how the heir of the Demon King ended up as the great hero's newborn son.
He smirked.
Well… it's a long story.
Arthur lifted his baby fingers to mimic air quotes.
After that hero "sealed" our entire family, Father began storing mana. For years. And a few weeks ago… he finally gathered enough power to send one of us outside the barrier.
His eyes hardened, remembering.
But our physical forms are far too powerful. So Father could only send a soul.
A proud grin stretched across his tiny face.
My sister and I fought for the honor of escaping first—to break our family free. She's strong. Terrifying, even. But…
He dusted his hands theatrically.
I'm here. That says enough.
He stopped beneath the window, moonlight spilling over him.
Father launched my soul beyond the barrier—and it switched places with the soul of the hero's real child. So the hero's son is currently trapped inside the barrier in my true body… and I'm stuck inside his weak, frail, magic-deficient infant form.
He sighed dramatically.
Thank the Abyss the hero didn't have a daughter. How awkward would that have been? I have too much dignity for that mess.
Arthur stretched his arms, cracked his knuckles (adorably), and rolled his miniature shoulders.
"Time to work," he muttered—though it came out as cute baby babble.
A black-purple magic circle flared beneath him.
Electric sparks of demonic lightning swirled through the nursery, rattling toys, shaking the crib, and making the curtains whip wildly.
The room glowed with power far too dangerous for a baby's body to handle.
But before the spell reached its peak—
pffft.
The storm flickered.
Sputtered.
And died.
Arthur stood in the middle of the room, covered in smoke, looking offended.
"Huh??" he squeaked internally. This body doesn't have enough mana to break the seal!?
He crossed his tiny arms.
Expected. It would take far more power than THIS to shatter a barrier made to imprison my father. Still…
His expression softened with thought.
Apparently this body has two mana cores. One belonging to the hero's son—some disgusting light core—and then MY dark core. But this infant body can only handle about one percent of my real strength.
He slumped dramatically onto the floor.
I guess I'll have to stick around for a while… as Arthur Einshorn. The son of that nauseating hero.
He sighed like a tired old man in an infant's shell.
Crawling back to his cradle, he muttered darkly, Well… a long day awaits. Better rest this fragile body while I can.
He pulled the blanket over himself—
Then paused.
Something felt… off.
A faint creak echoed from the nursery door.
Arthur slowly turned his head.
Three little faces were peeking through the crack in the doorway.
Elsa, Anna, and Bliss. All wide-eyed. All sparkling with sisterly affection.
Before he could react—
"ARTHUUUR!!"
"HE'S AWAKE!!"
"CUTIE!!"
They burst inside like a stampede of tiny wild beasts.
"LET GO OF ME, PEASANTS!!!" Arthur screamed mentally as Elsa scooped him up.
Anna squeezed his cheeks.
Bliss climbed onto him like a silent assassin.
All three piled onto him with endless cuddles.
STOP!! NOT THERE!!! MY RIBS!! THAT PLACE IS OFF-LIMITS!!! TOO MANY HANDS!!! HELP!!! NOOOOOOO—!!!
The scene zoomed out as the three girls smothered their baby brother in affection.
The camera pulled back through the window, rising into the night sky—
where countless stars shimmered peacefully above a world completely unaware that the heir to the Demon King had just begun his new life…
in the most chaotic family imaginable.