In this world, every child is born with two things inside their soul:

A Core
and
a Spirit Beast

No one knows where the Cores come from.
No one knows who created the Spirit Beasts.
They simply exist… as if the world itself placed them inside humans.

The Core is the source of power.
The Spirit Beast is the living manifestation of that power.

People grow up alongside their beasts.
They train together.
They fight together.
They live together like true partners.

But there is a terrifying truth of this world:

> If a Core is destroyed… the Master will die.
If a Spirit Beast is killed… the Master will feel the same pain and slowly die with it.



That is the contract no one can escape.

Because of this bond, wars are feared.
Battles are not just battles.
They are life-or-death promises between a human and their beast.

Some Spirit Beasts fight with fire.
Some with speed.
Some with shadow.
Some with sound.
Each Core awakens a different destiny.

People form teams.
Kingdoms build armies of Masters.
Tournaments decide rank, wealth, and survival.

But beneath all of this lies a darker question:

If no one knows where Cores come from…
who is controlling their fate?

Core Clash is the story of a world where
power is shared,
pain is shared,
and death is shared —
between a human and the beast born with them.

Welcome to a world where every human is born with a partner — a Spirit Beast — a creature of pure energy that shares their soul. Together, they fight, grow, and protect each other. When a Spirit is hurt, its master feels the pain. When a Spirit dies… the master's soul shatters forever. That is why the first and only rule of Spirit Battles exists — No killing. Defeat, yes. Destruction, never.


The announcer's voice echoed across the small town arena, riling up the crowd. Colorful banners flapped in the wind as two Spirit Masters faced off in the sandy ring, gauntlets glowing.


Riku's right hand tightened around his silver-blue gauntlet, its core shining like captured lightning.


"Alright, partner… let's end this in style!" he whispered with a grin.


A crackle of light burst from his core — a streak of silver fur and glowing eyes hit the ground. Bolt, his Wolf Spirit, growled, sparks dancing across its fur.


Across the ring, another spirit — a bulky Earth-type boar — stomped the ground, dust rising.


Riku's heart pounded. This was it. The final round.


The wolf blurred, a living streak of lightning.


A single, explosive impact shook the arena. The boar spirit squealed, its form glowing before dissolving into a flash of light — returning to its master's core, exhausted.


"Yes!" Riku yelled, pumping his fist in the air.


Bolt howled triumphantly, tail wagging.


The audience cheered as Riku ran to scoop Bolt into a hug. "We did it, buddy!"


On the edge of the arena, a short-haired woman in a workshop apron smiled — Riku's mother, a known Spirit Engineer. Beside her, a younger boy — Riku's neighbor and best friend — jumped excitedly.


"That Thunder Pounce was perfect!" his mom added, proud but calm.


Riku scratched the back of his head, grinning sheepishly.


"Heh, I told you guys we'd make it past the first round."


The sunlight poured onto the arena, and for a moment, Riku c


ould feel it — this was only the beginning.


Chapter 1 - Chapter 1 “The Day Thunder Roared”