The rule activated at 2:13 AM.
Ren barely had time to process the update before the world shifted. The colony grid above Tokyo shimmered, and a circular barrier erupted from the asphalt beneath his feet, expanding outward in a flawless sphere. Mirai lunged toward him, blood already spiraling from her palm, but the barrier sealed inches before her fingertips could reach him.
"Ren!" she shouted, striking the surface. Her constructs dissolved on contact.
Yuji slammed his fist into it next. Nothing.
Midoriya tested its structural density with controlled bursts. The barrier didn't even ripple.
Inside, sound dulled. The city beyond blurred as if seen through deep water. Ren stood alone in a silent district of shattered buildings and empty streets.
His phone glowed faintly.
Isolation Match Initiated.
Opponent Pending.
Opponent pending.
He exhaled slowly. "So that's how it is."
The air inside the sphere grew heavier. Cursed energy density began rising unnaturally, like pressure building in a sealed chamber.
They weren't sending a person first.
They were testing him.
The ground cracked three streets away.
A mass of blackened limbs tore itself out of a collapsed subway entrance. A special-grade curse—multi-jointed, with a skull-like mask fused into its torso—screamed as it lunged toward him. Its energy signature alone warped the pavement beneath it.
Ren didn't hesitate.
Boundary Erosion activated instantly.
The air around the curse compressed at sharp angles, folding its forward momentum into itself. Its limbs buckled unnaturally as space constricted around its joints. Ren stepped in, layering his quirk over the distortion—reducing resistance, accelerating his strike beyond natural velocity.
His fist landed.
The compression detonated inward.
The curse imploded in a violent burst of fractured bone and corrupted energy.
The isolation barrier absorbed the shockwave.
Ren's phone updated.
Points +10.
He barely had time to steady his breathing before another presence emerged. This one rose from the side of a high-rise, its body composed of shifting metallic blades fused with human silhouettes screaming within. A curse-user hybrid—someone who had already evolved within the Culling Game.
"Points," the creature rasped.
It launched a storm of slicing projectiles.
Ren warped the air again, bending trajectories mid-flight so the blades missed by inches. He advanced, compressing the space around the hybrid's core. The distortion crushed its metallic limbs inward as if gravity had spiked locally.
But it adapted.
The blades began vibrating at counter-frequencies, destabilizing his compression field.
Ren adjusted instinctively, narrowing the distortion radius and striking at the center mass instead of the outer limbs. The second impact shattered its torso entirely.
It fell.
Points +12.
The cursed energy density inside the sphere continued rising.
They were feeding it.
A third presence emerged—then a fourth.
Within the next fifteen minutes, Ren fought continuously.
A serpentine special-grade that phased through shadows. A grotesque stitched curse that regenerated faster than he could dismantle it. A former sorcerer driven feral by colony pressure.
Each time, he adjusted.
Each time, he survived.
Boundary Erosion sharpened with every engagement. The distortions became cleaner, more precise. Instead of overwhelming blasts, he compressed selectively—crushing cores, redirecting kinetic force, turning enemies' own movement against them.
But the cost was building.
His breathing grew uneven. Blood ran from the corner of his mouth. The isolation barrier hummed louder, reacting to each spatial collapse inside it.
Then the temperature dropped.
The asphalt beneath his feet dampened.
A faint sound of water echoed—though there was no rain.
Ren turned slowly.
The air behind him split open like a surface tension tearing apart.
Water flooded outward in a tidal surge, swallowing the street instantly. Within seconds, the environment transformed. Buildings dissolved into coral formations. Streetlights became seaweed-like structures swaying in artificial currents. The sky above blurred into an endless ocean surface.
A domain.
Not fully enclosed—but layered within the isolation barrier.
From the depths, a massive silhouette emerged.
Four arms. A grotesque face stitched into its torso. Eyes wide and gleaming with amusement.
Dagon.
"So much cursed energy," Dagon murmured, voice echoing like something speaking through water. "So much… potential."
Ren steadied himself as water pressure crushed around his body. Movement felt heavier instantly.
"So this is the next test," he muttered.
Dagon lifted one hand.
Shikigami erupted from the oceanic environment—razor-toothed aquatic horrors surging toward Ren from every angle.
He activated Boundary Erosion again, compressing the water around him into hardened zones that deflected the first wave. But underwater distortion behaved differently. Refraction altered perception. His compression fields dispersed faster under fluid resistance.
A shikigami tore across his shoulder.
Another struck his side.
Blood clouded into the water.
Ren clenched his jaw and forced a stronger distortion outward, collapsing several creatures at once. The water rippled violently as space bent within it, sending shockwaves through the coral skyline.
Dagon laughed.
"You bend space," the curse observed. "But space bends back."
The ocean pressure intensified.
Water condensed around Ren's limbs, restricting movement. Shikigami numbers doubled. They weren't testing him anymore.
They were drowning him.
Ren pushed harder.
The distortion radius expanded dangerously, warping the domain itself. Coral structures cracked. Ocean currents twisted unnaturally. But the fluid medium resisted stable compression. His quirk struggled under the density.
Another strike pierced through his guard.
He sank to one knee.
Vision blurring.
Breathing impossible.
Dagon descended slowly through the water toward him, massive shadow eclipsing the faint light above.
"You will evolve," Dagon said calmly. "Or you will feed evolution."
Ren tried to stand.
His limbs wouldn't respond fast enough.
For the first time since the isolation began, the word surfaced clearly in his mind.
Helpless.
Dagon raised all four arms.
The water condensed inward like a crushing abyss.
And then—
The ocean split.
Not warped.
Not compressed.
Split.
A gravitational force slammed downward from above, parting the artificial sea as if an invisible planet had dropped into it. The pressure reversed instantly. Water surged upward instead of down.
Dagon's eyes widened.
A figure descended calmly through the fractured domain, boots touching the submerged street without sinking.
Blonde hair. Black outfit. Calm expression.
Yuki Tsukumo.
"You're playing rough with kids," Yuki said lightly, rolling her shoulders. "That's not very sporting."
Dagon snarled and unleashed another wave of shikigami.
Yuki didn't dodge.
She stepped forward.
Mass accumulated.
The very air thickened around her.
Her punch landed with catastrophic density.
The entire ocean domain fractured outward in a violent implosion. Coral structures disintegrated. Water evaporated into steam as the layered environment collapsed under raw gravitational force.
Dagon was launched across the artificial sea, body tearing through warped space before crashing into the barrier wall.
The domain shattered.
The street returned.
Ren collapsed forward onto dry asphalt, coughing violently.
Yuki glanced back at him casually. "You've got ridiculous output," she said. "But you're fighting like you've got something to prove."
Dagon began regenerating, shrinking
Yuki cracked her neck slightly.
"Let the adults handle disaster curses."
She stepped forward again.
And this time, the ground itself trembled under the weight of her strike.