Both stood frozen, locked in a cold, silent stare. A moment passed.
UltSans raised his right hand slowly. A small, glitching portal flickered open beside him, its edges jagged like a corrupted file. He reached inside. When he withdrew, the portal sealed itself shut—and in his grasp was a syringe. Its contents swirled with an unnatural, molten-red fluid, glowing like magma infused with something deeper… something alive. The light within pulsed like a heartbeat, radiating an intense red aura.
Without a word, UltSans tossed it.
Doom Slayer caught it effortlessly.
:: SCAN COMPLETE ::
:: SUBSTANCE UNRECOGNIZED ::
:: NO MATCH IN EXISTING DATABASE ::
:: POTENTIAL EFFECT: EXTREME ENHANCEMENT ::
The Praetor Suit's voice echoed in his helmet. Whatever was inside this syringe wasn't identifiable—not demonic, not earthly. But the suit confirmed one thing: it would enhance him.
Doom Slayer paused. Then, without hesitation, he jabbed the syringe into his neck and emptied it.
The effect was immediate.
He dropped the syringe. It shattered as it hit the ground, glass and metal fragments scattering like shrapnel. His body convulsed. He coughed—hard, violent—and blood splattered inside the helmet, unseen from the outside. Red veins surged across his skin, glowing faintly through the gaps in his armor, like cracks in cooling volcanic rock. Smoke hissed from his limbs. The world around him began to warp.
Then—a red glow.
It wasn't from within.
He looked up.
The sky above him—if it could even be called a sky anymore—was obscured by a colossal red aura radiating from UltSans. Doom Slayer's vision blurred at the edges, nearly overwhelmed by the sight. He couldn't make out details—only smoke, red veins, and the sheer heat. But he saw them.
Human souls. Floating.
Not tens. Not thousands. Billions.
Over 8 billion souls churned in a wide orbit around UltSans—flickering, drifting, whispering, screaming. And in the center, a handful glowed brighter than all the rest. True Souls. Human essence pushed to its purest state. A dozen, maybe more, burning like small stars around UltSans' form, circling him like faithful sentries.
Doom Slayer staggered, not from fear—but from the overwhelming weight of what coursed through him. His body boiled. The heat scorched him from the inside out. Muscles spasmed, armor hissed, pain pulsed through every nerve.
He clenched his fists.
This wasn't just a fight anymore.
This was war—at its most absolute level.
The ground beneath Doom Slayer vibrated—subtle at first, then stronger, as if the world itself was reacting to what had just been unleashed inside him. His boots pressed deeper into the cracked terrain as the heat pouring from his body grew too intense for even the scorched volcanic rock to ignore.
His arms twitched.
Not from weakness, but from the overwhelming energy crawling under his skin, fighting for control. Every joint in the Praetor Suit hissed. His fingers curled and uncurled, red veins glowing brighter beneath the armored plates, some visible through stress fractures along the surface.
Then—movement.
A flicker of smoke curled from the vents of his backplate, trailing upward like steam off molten iron. It wasn't part of the suit's cooling system. The smoke came from him. The injection had changed something deep within, something the armor was never designed to contain.
His HUD glitched again. Entire systems dropped for a moment—then rebooted with scrambled warnings and unreadable code. A dull, high-pitched buzz echoed inside the helmet, broken static, short-circuited data feeds flickering in and out.
:: Internal temperature critical :::: Neural relay interference detected :::: Armor phase integrity—UNSTABLE :::: Conscious override active ::
The suit was trying to adapt, trying to recalibrate around the chaos now spiraling through his blood. It wasn't working.
He staggered—just slightly. Enough to notice. Enough for him to feel it: this wasn't a power-up. This was possession by force. Something else was clawing at the edge of his thoughts, some primal scream buried beneath layers of rage and instinct.
Doom Slayer brought his hands up, slowly, deliberately, as if expecting them not to obey. What he saw sent another pulse through his spine. Red veins now covered his gauntlets like roots of light. They weren't just glowing—they were moving, crawling, pulsing in sync with his heartbeat. Thin arcs of energy traced across his knuckles, and tiny embers floated off his skin, like the air around him was starting to burn away.
The veins stretched up his arms, branching toward his shoulders and neck. They moved like they were alive.
Smoke drifted from the joints of his suit—thickening, darkening, mixing with the dim red mist that now bled from every crack and seam. His breathing was ragged. Not loud—but shallow, controlled, and heavy. Each inhale was labored. Not because he was exhausted, but because the air itself felt like it was fighting back.
The red glow around his body intensified. It wasn't light—it was pressure. A crushing aura that made the air ripple, like invisible waves exploding outward with every pulse from his core. His shadow flickered on the ground beneath him, not steady—dancing like fire behind cracked glass.
Above him, the sky warped.
Or what remained of it.
UltSans hovered high above, bathed in apocalyptic crimson light. Souls swirled around him—unimaginable in number. Doom Slayer's optics adjusted, sharpening, struggling to resolve the chaotic motion.
He saw them.
Billions.
Endless.
An orbiting sea of humanity's essence, screaming in silence, whispering in static, crying without breath. The sky was filled with them—layered, infinite, stretching across reality like a broken halo. But those weren't what burned into Doom Slayer's vision.
It was the ones closest to UltSans.
Ten—maybe more.
The True Human Souls.
They didn't drift—they held position. Burning white-hot, blue-hot, orange-hot—souls at their peak. Souls that had transcended mortality. They spun in a slow, deliberate circle behind UltSans like a crown of divine fire, each one casting massive rays of light that split through the soulstorm.
Doom Slayer's vision faltered again. The red aura around him was interfering with his sensors, creating feedback loops. His eyes blurred. His vision swam with doubled images, HUD icons bleeding together. All he could see now was a silhouette—UltSans' form, surrounded by a corona of souls.
He wasn't afraid.
But something deep within him… twisted.
A new kind of discomfort. Not pain. Not rage.
Disruption.
He felt his balance shift, as if something inside him wanted out—something that wasn't his. His muscles tensed involuntarily. A tremor ran up his spine. His left shoulder jerked without command. He forced it still.
The armor creaked.
His helmet, already cracked in places, now showed hairline fractures glowing faintly red from within. The front visor distorted, no longer reflecting clearly—only rippling with heat and energy. From the outside, the visor shimmered like liquefied fire glass, warping anything behind it.
And behind it, there was a faint glow.
His eyes.
They couldn't be seen—but their presence could be felt. A deep red intensity burned behind the mask—just barely visible with each flicker of light, like twin furnace-cores staring through the glass.
He wasn't breathing normally.He wasn't even standing normally anymore.
His stance had shifted—wider, heavier. His posture was tense, rigid, like a mountain holding back a volcanic eruption. His fists were clenched tight, but his arms twitched every few seconds, as if resisting a surge of power trying to rip them apart from the inside.
The smoke around him thickened.
It was no longer fading—it was spreading. Following him like a creeping fog, dense and red at the edges, almost sentient in the way it clung to his silhouette. Every movement left behind a trail of glow and mist.
UltSans hovered, unmoving, watching.
The two locked in place.
Reality around them wavered.
Time seemed to stall.
And in the void of that moment, in the scorching pressure of silence, Doom Slayer slowly tilted his head, the gesture minimal—mechanical—but deliberate.
His armor hissed. The internal temperature alerts blinked in and out. His body strained.
But he stood firm.
The fire inside him hadn't consumed him.Not yet.And that meant he could still aim it.
Still use it.
Still rip something apart with it.
They stared at each other, unmoving. A line drawn between gods.
Then—UltSans moved.
In a single breath, the swirling storm of humanity—the billions of souls orbiting him—collapsed inward. Like a singularity snapping shut, the entire cosmic vortex of consciousness rushed into his core, vanishing in a blinding red flare. The air cracked. Space folded. And just like that, all the souls were gone—inside him.
The silence was deafening.
UltSans' gaze shifted. His left hand rose.
With a sudden jerk, he threw his hand forward—fingers flaring blue. Across the battlefield, Chara jerked backward, her body yanked violently by blue magic. A red soul—their soul—flared faintly in front of their chest, flickering like a candle in a storm. She hit the ground, hard, skidding across the rock.
Then the pressure changed.
She floated upward for a second—then was slammed sideways again, as UltSans casually pushed her away with another flick of his fingers.
He didn't say a word.He didn't need to.
This was no longer a shared war.This was his war.
A 1v1. No distractions. No interruptions.This went further than personal.
UltSans' expression was unreadable—but his posture said everything. Determination radiated off him in waves so hot it shimmered in the air. He was done holding back. And he was too far gone to be stopped by anyone else.
He took the first step.
Then another.
Then he broke into a run.
Doom Slayer didn't hesitate.
His boots thundered into the earth as he launched forward, his weight now propelled by something far beyond adrenaline. Every stride carved molten cracks into the stone beneath him, his red-veined form trailing smoke and power. The distance between them closed in seconds.
And then—
Impact.
Their fists collided with a shockwave that shattered the sound barrier. The air detonated. The ground beneath them exploded outward in concentric cracks. Neither moved back. Neither gave ground. Their arms trembled mid-clash, muscles locked, teeth gritted, power bleeding off their bodies like steam.
Then came the flurry.
A left hook from Doom Slayer—parried by UltSans' forearm, which flexed like it was built from reinforced bone. UltSans countered with a vicious, rising uppercut—not aimed at the chin, but raking upward like a claw strike, his fingers stiff, slicing the air. Doom Slayer caught the blow with his own rising guard, and the force lifted both of them off the ground for a split-second.
They landed in sync—feet smashing the terrain into rubble.
And it kept going.
Doom Slayer lunged with a brutal punch aimed for the gut—UltSans twisted sideways, his arm lashing out across Slayer's ribs like a cleaving arc. It scraped across the armor with a grinding, metal-on-metal screech. Doom Slayer countered mid-step, his fist slamming into UltSans' shoulder, sending him skidding back—but not staggering. UltSans used the momentum, spinning, his next blow coming around like a spinning sawblade of raw magic.
They were fists. But they weren't just fists.
Every punch was a hybrid—part hammer strike, part clawed mauling. Their fingers weren't sharp, but the intensity made it feel like they were. Every blow ripped the air. Every blocked strike still cracked bones and sent tremors across the battlefield. Dust storms rose with every movement, their energy carving through stone and air alike.
UltSans ducked low, surged forward—slammed his fist into Doom Slayer's gut. Doom's armor flexed inward like rubber before bouncing back with a kinetic pulse, forcing UltSans a step back. But Doom grabbed him mid-recoil—shoulder-checked him—punched downward like he was trying to drive his fist through the planet.
UltSans caught it.
The two froze again—locked hand to hand, fists trembling mid-collision, arms straining, veins pulsing, smoke hissing off their skin.
Then they exploded apart in opposite directions—dust and flame rising between them.
But neither stayed down.
UltSans was already charging again, teeth gritted, eyes glowing like suns. Doom Slayer roared wordlessly, fists clenched, red smoke curling from his shoulders. They collided once more—elbow strikes, backhands, clawing punches that tore pieces from each other's armor. Every attack was a fusion of rage and precision, instinct and fury.
It wasn't elegant. It wasn't martial.
It was primal.
Two gods trying to tear the other apart with their bare hands, driven by the singular will to end this. The battlefield had no air left. No stillness. No balance. It was quake after quake. Roar after roar. Punch after clawed punch.
And neither was backing down.