The descent was a brutal, grinding testament to Seiji's growing power and resolve. Each floor presented a new horror: a chimeric beast with venom-dripping scorpion tails, a spectral wraith that siphoned warmth from the very air, a cavern of pulsating, acidic fungi. The floor bosses grew in monstrous stature and cunning. One, a Juggernaut—a mindless, thirty-foot-tall giant of granite and rage—nearly ended his journey. Its fists fell like meteors, and one glancing blow sent him careening through a pillar, his armor screaming in protest, his body screaming louder. For a moment, he lay pinned, the colossal foot raised to crush him. It was the combined might of Kiva's dark chains binding the giant's leg, OOO's Gatakiriba clones swarming its torso as distractions, and a final, shattering Agito Rider Kick to its knee joint that bought him victory. He stood panting over the dissolving stone form, the Vanguard system integrating the data from each near-death experience.
Finally, after what felt like an eternity of blood, sweat, and systemic adaptation, he stood before the gate to the 40th floor. The air here was still and heavy, tasting of old dust and profound finality. He pushed the gate open.
The stench that hit him was a physical blow—not of rot, but of deep, ancient earth, cold stone, and a faint, metallic tang of old blood. This was no vast arena. It was a tomb. A single, cavernous chamber, its walls carved with faded murals of epic battles and a forgotten kingdom. Towering in the center was a massive stone coffin, intricately carved with runes that pulsed with a sickly, dim light.
As Seiji took a cautious step forward, the runes on the floor flared. A magic circle, blood-red and complex, ignited around the perimeter of the room, sealing the entrance with a wall of shimmering energy. At the same time, the lid of the coffin cracked with a sound like a mountain splitting, then slid aside with a grating rumble.
Inside lay a corpse. It was humanoid, but massive, easily eight feet tall. Its flesh was desiccated but intact, grey and leathery. Its most striking feature was the giant, bestial skull that served as a pauldron on one shoulder, and its body was wrapped in heavy, black chains that seemed to bind it even in death. It wore the tattered remnants of what was once grand, barbaric armor.
As the magic circle's energy washed over it, the corpse reacted. Its eyes snapped open, glowing with a vacant, piercing white light. A guttural, mindless roar erupted from its throat, a sound of pure, unrestrained violence. It moved with shocking speed, launching itself from the coffin, chains rattling, and charged.
Seiji barely dodged, the wind pressure from its passing staggering him. He skidded to a halt, instantly analyzing. "The body is massive, but the speed is quite fast. If so..."
His mind became a command console. "Simultaneous Form Access: Agito Burning Form, Kiva Dogga Hammer, OOO Sagohzo Combo."
His aura shifted in a kaleidoscope of light and reshaping metal. The sleek lines of Agito's Burning Form, glowing with contained thermal energy, became the base. Over his right arm, the colossal, purple-metal projectile of the Dogga Hammer materialized, crackling with the purple electricity of the Franken race. And throughout his body, the immense, earth-shaking power of the Sagohzo Combo settled, making his every step feel tectonic.
He didn't wait. He punched the stone floor. The Sagohzo power transmitted through his fist, and a localized gravitational field erupted around the charging corpse. The stone beneath its feet cracked as it was suddenly forced down, its blinding speed reduced to a labored, grinding stomp.
Seiji charged in return. He rushed forward, not to strike, but to build momentum, the purple electricity arcing wildly. He closed the distance and threw a straight punch, the Burning Form's fiery fist wreathed in superheated aura and amplified by the purple electricity. The impact was thunderous. The punch, carrying the explosive force of fire and the crushing weight of earth, slammed into the corpse's chest, hurling it backward to crash against the far wall. The stonework spiderwebbed with cracks, and dust filled the air.
But as the dust settled, the corpse pushed itself upright. Its chest was scorched, but unbroken. And on its lifeless face, the muscles pulled its lips back from its teeth in a grotesque, rictus smile.
"Smiling?" Seiji's voice was a mix of disbelief and exhilaration. "Interesting!" He took a fighting stance, his fist ready. "Bring it on!"
As if in response, the corpse also crouched, its pose that of a primal predator coiling its muscles. For a heartbeat, they were frozen, two warriors from different worlds, united by the language of combat.
Then, they moved as one.
The battle was a symphony of destruction. Seiji was a whirlwind of calculated power. He'd block a bone-shattering swing of a chained fist with the Dogga Hammer's projectile, the impact sending visible shockwaves through the air. He'd retaliate with a Burning Form's fiery kick that scorched the corpse's side, the smell of burnt leather filling the tomb. The corpse was relentless, its style a brutal, efficient savagery. It used its chains as whips, lashing out to entangle Seiji's legs. It charged head-first, the beast skull on its shoulder acting as a battering ram that Seiji only just sidestepped, the skull gouging a chunk out of the wall.
Seiji used the Sagohzo's power to anchor himself, becoming an immovable object to meet the unstoppable force. He traded blow for blow, his electrified, burning punches meeting the corpse's raw, mana-infused strikes. The sound was of clanging metal, shattering stone, and the grunts of two beings pushing their bodies to the absolute limit.
Time lost all meaning. There was only the next attack, the next dodge, the next impact.
Finally, after an eternity of combat, they clashed in the center of the room one more time, a final, simultaneous exchange of blows that sent them both flying backward to crash against opposite walls.
Seiji slid to the floor, panting heavily. The Vanguard armor had prevented catastrophic injury, but his entire body felt like one massive bruise; every bone screamed in protest, every muscle fiber was frayed. Across the chamber, the corpse was in a similar state. Its body was pockmarked with craters from his punches, one arm hung limply, and its chains were severed in several places.
Seiji pushed himself to his feet, his voice raw but filled with a strange, exhilarated respect. "I don't know if you understand me or not! But put all your strength into the final blow! O indomitable warrior who has fallen!"
The corpse responded not with a roar of mindless fury, but with a deep, resonant bellow that seemed to carry the weight of its long solitude. It was an acknowledgment.
They charged for the last time, both gathering every ounce of their remaining power. Seiji's right fist became the focal point. The orange glow of the Burning Punch, the violent purple arcs of the Dogga Electric Smash, and the crushing aura of the Sagohzo Impact swirled together into a maelstrom of destructive energy around his knuckles.
The corpse poured the last of its animating mana into its own fist, which glowed with a deathly, concentrated white light.
They met in the center.
The collision was silent for a split second before the world turned white. Then, a shockwave of pure force erupted, hurling stone fragments from the walls and floor. The magic circle sealing the room flickered violently. For a moment, the two attacks were locked in equilibrium. But the corpse was just that—a corpse, a vessel for power, not a living will. Seiji's trinity of Rider powers, fueled by his unyielding resolve, began to push back.
"ARRRGHHH!" Seiji roared, pouring every last shred of his being into the strike.
His fist overcame the white light. It shattered the corpse's arm, plowed forward, and pierced clean through its chest. There was a sound like shattering crystal as the mana core within was obliterated.
The corpse froze. The white light in its eyes faded, leaving behind empty sockets. It did not fall immediately. It simply stood, impaled.
Seiji, his arm still buried in its chest, gently lowered the massive form to the ground. He knelt, cradling the fallen warrior's head. "Even though I don't know who you are," he whispered, his voice now soft with exhaustion and respect. "But let me give you my respect! Thank you! You are a worthy opponent!"
As the last of the mana left its body, the grotesque smile on the corpse's face softened. It did not look pained or angry. It looked... satisfied. At peace.
The magic circle shattered into motes of fading red light. As it did, a single, perfect red sphere materialized above the warrior's chest. Seiji, his body aching but his spirit clearer than ever, reached out and touched it.
An image, vivid and overwhelming, flooded his mind.