Chapter 40: The Rot and the Sanctuary
Tomura Shigaraki stood in the center of Deika City, his red eyes burning with a manic, unadulterated hatred.
The battle was raging all around him. The Meta Liberation Army was clashing with the League of Villains, while the Vanguard of the Winged Sovereign descended from the sky like avenging angels. Tensei Iida was an emerald blur, shattering MLA ranks. Hawks was a crimson storm, neutralizing elemental threats. The board was slipping through Shigaraki's fingers.
"This is my stage," Shigaraki rasped, his voice vibrating with absolute malice. "The Master is gone. The old world is dead. And I am not going to share the ashes."
Shigaraki dropped to his knees. He slammed all ten fingers directly into the asphalt of the city square.
The awakening he had experienced against Gigantomachia paled in comparison to the sheer, nihilistic rage he felt now. A catastrophic, silent shockwave of pure, gray disintegration erupted outward. It didn't just crawl; it cascaded like a tidal wave of death. Buildings instantly turned to ash. MLA soldiers screamed as the dust consumed them. The rot was expanding in every direction, threatening to erase Deika City and every single soul inside it from the map.
High above the spreading apocalypse, near the peak of Re-Destro's central corporate tower, the Underground Student Cell was moving with desperate precision.
Izuku Midoriya, Katsuki Bakugo, and Shoto Todoroki sprinted down the lavishly carpeted halls of the MLA headquarters. The sounds of war echoed through the reinforced glass windows, but their mission was absolute: secure the MLA's satellite uplink data before the Commission could use it to frame the heroes or seize the network.
"Three guards ahead!" Todoroki warned, his right side frosting over.
"Don't stop!" Bakugo roared, leaping off the wall. He didn't use lethal force; he used a concentrated Stun Grenade flash right in their faces, while Todoroki swept their legs out with a slick sheet of ice.
Midoriya vaulted over the frozen guards, his Full Cowling crackling with green lightning as he shoulder-bashed the heavy oak doors of the central server room off their hinges.
"I'm at the console!" Midoriya yelled, pulling a decrypted Swarm flash drive from his tactical vest and jamming it into the mainframe. "Downloading the satellite network keys now! Thirty seconds!"
Suddenly, the entire skyscraper groaned. A sickening, grinding sound echoed up from the foundation.
Bakugo ran to the shattered window, looking down at the city. His crimson eyes widened in sheer horror. A massive, gray wave of decay was expanding from the city center, turning everything it touched to dust. The base of the MLA tower had just been hit.
"Deku!" Bakugo yelled, sparks flying from his teeth. "The building is rotting from the bottom up! We need that data right damn now!"
"Twenty seconds!" Midoriya grit his teeth, the progress bar on the screen inching forward as the floor beneath them began to violently tremble.
Hovering high above the city, Rei Arata watched the gray wave of death expanding.
His Emotion Sight was flooded with the sheer terror of tens of thousands of people. Shigaraki's decay was moving too fast. Tensei couldn't outrun a 360-degree wave to save everyone. Rin couldn't open a portal large enough to evacuate an entire city.
If I cannot move the people to safety, Rei thought, the cosmic energy in his chest roaring like a dying star, then I must bring the safety to them.
Rei closed his eyes behind the silver moth-mask. He pushed his innate Quirk—the cosmic synthesis that allowed him to borrow the Swarm's powers—past its absolute limit. He didn't just want to channel the powers anymore. He commanded his cosmic core to adapt, to fuse, to evolve.
He drew upon Rin's Sanctuary Phasing, Akio's Aegis Pulse, and the Eternal Vitality healing factor.
His civilian DNA screamed in agony as the powers collided, but Rei forced them together. The violet butterflies on his cloak dissolved, sinking directly into his skin.
A new, permanent synthesis was born. The Sovereign did not just wield the pocket dimension; he became its anchor.
Rei threw his arms wide open.
"PLANETARY PHASE!"
The sky above Deika City literally shattered like glass.
The silvery-blue, starlit void of the Sanctuary Phasing dimension spilled out, forcefully overlapping with reality itself. A massive, shimmering dome of iridescent energy expanded over a two-mile radius, engulfing the Vanguard, the Origin Trio's collapsing tower, the MLA, and the League of Villains.
But it wasn't just a spatial portal anymore. It was fused with the Aegis Pulse.
The edge of the Sanctuary dome slammed into the ground just as Shigaraki's decay wave reached it. The gray disintegration clashed violently against the newly formed Dimensional Shield. The sheer density of the spatial-kinetic barrier was astronomically higher than Akio's original shield. The decay chewed at the golden-blue light, but the barrier held absolutely firm, stopping the wave of death dead in its tracks.
Inside the overlapping dimension, the air was suddenly filled with thousands of glowing, violet-gold butterflies.
They weren't just decorative. The dimension itself had become the home of his innate power, infused with a localized, passive Eternal Vitality. As the butterflies landed on the exhausted heroes, the battered Vanguard, and even the terrified MLA civilians, their wounds began to rapidly knit together. It wasn't as instant as Akio's direct touch, but it was a miraculous, city-wide healing factor.
Down on the street, Hawks stared in awe as a deep gash on his arm sealed itself under the glow of a butterfly. "What kind of god is this kid?" the Number Two hero breathed.
Rei Arata descended slowly from the starlit sky, his breath coming in steady, powerful rhythms. The permanent fusion of the dimension had drastically shortened his own regeneration time; the cosmic strain of the synthesis healed almost instantly. He was a flawless, untouchable king within his own domain.
He landed gently on the ash-covered asphalt, just a few yards away from Tomura Shigaraki.
The leader of the League of Villains stared at the shimmering Dimensional Shield that had halted his ultimate destruction, his red eyes twitching with absolute fury.
"You," Shigaraki snarled, his voice breaking. "You're cheating. You're breaking the rules of the game!"
"There is no game, Tomura," Nocturne's dual-toned voice echoed with terrifying, absolute authority, resonating through the entire fused dimension. "You possess the power to rot the world. But I have evolved the power to preserve it. Your decay ends where my shadow begins."
High in the crumbling tower, the downloading screen hit 100%.
Midoriya yanked the flash drive from the console just as the floor beneath them began to turn to gray dust from the residual decay.
"Got it!" Midoriya yelled.
"Jump!" Todoroki commanded, blasting a massive hole in the reinforced glass window.
The Origin Trio leaped from the collapsing skyscraper into the night sky. But they didn't fall to their deaths. They fell into the overlapping, starlit void of the Sanctuary.
A swarm of golden-violet butterflies surged upward, catching the three UA students in a cushion of spatial energy and gently lowering them to the safety of the dimensional floor. Midoriya clutched the data drive to his chest, looking up at the colossal, starlit dome protecting the city, and the masked Sovereign standing toe-to-toe with the deadliest villain in history.
The war in the shadows had truly begun.