….
What [Sun Breathing] actually is?
A sword technique that enhances physical capabilities through specialized breathing patterns.
Dabi's fundamental problem was cellular and genetic - his body at the tissue level lacked heat-resistant cells.
And the cancerous body on top of it.
However, the [Sun Breathing] improved cardiovascular and muscular performance, but it couldn't fundamentally alter cellular structure or grant heat resistance.
And the technique alone doesn't provide any true fire manipulation - the 'flames' are merely a visual byproduct, while its real effect lies in enhancing strength, speed, stamina, and oxygen flow to the muscles.
But that didn't mean it was useless.
Enhanced oxygen circulation and overall physical conditioning helped him heal faster from burns. The extreme training increased his mental fortitude to push through pain, and masterfully control his quirk. Better stamina meant he could use his quirk slightly longer before exhaustion compounded the damage.
The benefits were indirect at best: perhaps a 5-10% improvement.
In essence, it was asking whether athletic conditioning could overcome a genetic incompatibility, like wondering if marathon training would allow someone allergic to bees to safely handle a beehive.
And the process itself had been hellish.
[Sun Breathing] required intense physical training that pushed the body to its absolute limits. For someone whose body was already fragile in specific ways, learning it had been torture.
The harsh truth was that [Sun Breathing] was fundamentally a technique for humans fighting demons with swords.
Dabi needed something that addressed quirk biology - something like Endeavor's natural heat resistance, or some form of quirk therapy.
And the conclusion was: a breathing technique, no matter how advanced, couldn't bridge a genetic mismatch.
But the [Super Soldier] Serum was a relatively different matter.
Rather than merely increasing strength, the serum enhances the body at the cellular level - improving muscle density and efficiency, reinforcing bone structure, accelerating healing, optimizing metabolic processes, strengthening cellular regeneration, raising pain tolerance, and greatly increasing overall physical resilience.
The formula was designed to refine human biology itself, bringing the body closer to its theoretical peak potential.
Here, the critical question was–
Does 'peak human potential' include developing heat resistance that wasn't in his genetic blueprint?
The answer was complicated - the serum enhanced what already existed without rewriting DNA.
Dabi's DNA said 'ice resistance, not fire resistance'.
Also heat resistance wasn't 'peak human.'
Normal humans didn't have natural resistance to 2000+ degree flames. The serum brought you to peak human potential, and humans simply weren't fireproof.
Realistically, the chances of meaningful improvement were around 30-40%.
The most likely outcome was a compromise: his healing factor would let him recover from burns in hours instead of days.
He could use his quirk more frequently with reduced consequences. And maybe could keep his cancer cells from multiplying.
But he would still hurt when used his quirk.
The only difference was scale: from 'completely unusable without suicide' to 'usable with significant cost.'
Instead of third-degree burns after thirty seconds, maybe he would get first-degree burns after five minutes, and they would heal by the next day.
That's the reason [Arachnid Genome] plays a crucial role in his [GENETIC MILESTONE SYSTEM].
The radioactive spider bite was more than a simple enhancement - it triggered a form of genetic rewriting, effectively integrating spider traits into human DNA.
The result was the emergence of entirely new biological capabilities absent from normal human physiology, and the heightened precognitive awareness known as spider-sense.
Fundamentally it altered cellular structure at the genetic level, and this was very different from the [Super Soldier] serum, which optimized existing biology.
But all three together?
[Sun Breathing], [Super Soldier], and [Arachnid Genome]?
The chances of gaining functional fire resistance jumped to 60-75%.
[Sun Breathing] maximized oxygen flow to superhuman cells, enhanced blood circulation for better heat distribution, and provided mental conditioning to endure pain.
[Super Soldier] Serum enhancement perfected the spider-hybrid cells, increasing durability by 50% on top of the spider base, amplifying the healing factor dramatically (recovery rate increased by 500%), and ensuring peak cellular efficiency for heat dissipation.
[Arachnid Genome] rewrote cellular structure entirely, providing base durability increase of 40%, a healing factor with 300% recovery rate, and fundamentally new biological capabilities.
Triple-enhanced, Dabi could use his flames for sustained periods with only minor to moderate burns that healed rapidly. He could fight multiple battles per day, use his quirk as his primary combat method, and recover between engagements.
Essentially, he would become functionally cured for practical purposes, even if technically his cells still burned.
If he survived and completed all three evolutions, his physical capabilities would be beyond imagination:
Strength: 20-30 ton range.
Speed: Casual bullet-timing, probably supersonic movement.
Healing: Wolverine-lite, serious wounds healing in hours.
Durability: Tank hits that would kill normal heroes.
In the current world of Quick, he would be high S-tier, probably surpassing even prime All Might in many ways.
The combination of Spider-Man mobility, Captain America's peak performance, breathing technique - stamina, and blue flames would make him one of the most versatile and powerful Heroes in this universe.
Maybe at some point Dabi would be so powerful that his fire quirk would become almost secondary to his other abilities.
He would finally be able to use it, yet no longer need to rely on it… Having reached his goal in the most roundabout way possible by becoming everything his father never wanted him to be.
The boy who burned himself trying to master flames would become the man who transcended the need for them entirely, while finally being able to use them anyway.
And that was exactly what was happening to Dabi's body right now.
….
[The U.A. High School - Medical Ward]
Inside the ICU, Dabi's body was undergoing a transformation that defied all known medical science.
Recovery Girl monitored the readings with a mixture of fascination, horror…. and hope.
Strands of genetic code that shouldn't exist were weaving themselves into his existing structure, and the cancer cells - once a death sentence - were being aggressively consumed, repurposed as raw fuel for his transformation.
His healing factor was accelerating exponentially. Bones that had been shattered were knitting back together with density far exceeding normal human capacity.
And through it all, the [Super Soldier] that had finally reached 100% completion was perfecting every change, optimizing every new capability.
His system display - visible only to him in his unconscious state - showed the progress:
======
[GENETIC MILESTONE SYSTEM]
THREE EVOLUTION PATHS:
| [BREATH OF THE SUN] - 100/100% ✓
| [SUPER SOLDIER] - 100/100% ✓
| [ARACHNID GENOME] - 11/100%
…
| LIFE SPAN LEFT: Calculating…
======
With the blood from his siblings being pumped into him, providing the genetic material and biological resources his body needed, the transformation was proceeding.
Slowly, the rattle in his chest smoothed out. The erratic heart rate stabilized into a deep, powerful thrum.
He was going to survive.
But when those turquoise eyes finally opened, the man who had closed them would be gone, replaced by a being that the world was not…. yet prepared to face.
….
[The Hallway]
Outside, the silence remained.
Fuyumi and Natsuo sat shoulder-to-shoulder, their worldviews fracturing as they tried to reconcile the image of their 'dead' brother with the 'Hero' they have been hearing in the news lately.
Shoto sat apart, his expression a mask of stoicism.
Rumi paced the narrow corridor with uncertainty written all over her face.
Gran Torino had tried to convince her to eat something, but the food sat untouched on a nearby table. Nearby, Eri slept fitfully.
That's when the temperature in the hallway rose noticeably.
!!!??Everyone looked up as the entrance doors opened.
Endeavor strode in, still in his Hero costume, flames crackling around his shoulders - who seemed to be reached directly from a mission.
At nearly two meters tall with a physique built from years of intense training, he was an imposing figure.
His turquoise eyes - the same eyes Shoto and Toya shared - swept the hallway with the predatory intensity of a man demanding absolute attention.
"Shoto." his voice boomed. "Your message said it was urgent. What is this?"
The truth was, Endeavor didn't even have his own son's contact, nor did Shoto have his until a few hours ago, when he took it from his sister.
So when the message came through, he dismissed it as a prank, some nobody testing his patience, until verification and cross-checking before the reality settled in.
The number belonged to his son.
He went still, eyes locking onto Fuyumi and Natsuo, before drifting to the assembled high-tier heroes: All Might, Aizawa, Mirko, and the veteran Gran Torino.
"Someone tell me what's going on." Endeavor's voice dropped half a register. "Why was I told to come to U.A. immediately? And why are my children sitting in a hospital corridor instead of at home?"
Rumi stepped into his path, her ears were pinned flat against her skull - an instinctual sign of lethal aggression. "You are Endeavor. Enji Todoroki."
"I am." Endeavor's eyes narrowed. "And you're Mirko. The Rabbit Hero." He looked past her, then back. "Why are you here? What does this have to do with–"
"Your son is behind those doors." Rumi interrupted, her voice a low, dangerous growl. "He is fighting for his life because he stood between a class of children and a pair of bioengineered god-killers. So maybe you could tone down the 'Number Two' act for five fucking seconds and be a human being."
Endeavor's flames flared. "My sons are right here." He gestured toward Shoto. "I can see them. So I don't know what you're–"
"Not those sons." Gran Torino said.
Everyone looked at him.
He was sitting in one of the plastic chairs with his arms crossed, looking about as concerned with Endeavor's presence as he would be with a change in the weather.
"....your other son."
Endeavor literally froze, his flames dimming to almost nothing.
"My other…" His voice had shifted, the booming command was gone, replaced by something quiet and infinitely more dangerous. "What are you talking about? I don't have any–"
"Toya." Fuyumi stood up, her voice trembling in sadness. "They are talking about Toya, Dad."
The name just sat there in the hallway.
Endeavor's expression went through several changes in rapid succession: confusion, cold disbelief, and then a flash of raw, jagged pain that he quickly tried to smother.
"This is… no. The investigation confirmed–"
"The investigation was wrong." Natsuo said flatly, his voice dripping with years of accumulated resentment–
"And it gets worse!!"
"You want to hear it? You want to hear where he ended up?" Natsuo was leaning forward now, his hands shaking, and the resentment that had been compacting inside him for years was cracking through the surface. "He was picked up by some freaky villains! You think about what that means? What would have happened to him if–"
He cut himself off, breath hitching before forcing the words out.
"By some miracle, he got out."
He pointed at Gran Torino, his finger was trembling.
"If that old hero hadn't taken him in… hadn't looked after him all this time, think about where Toya would be right now."
Endeavor turned to Gran Torino, the grief still lingering on his face as it sank beneath something more familiar - anger, the one thing he knew how to wield.
You? You held my son for six years and never–"
"He asked me not to." Gran Torino didn't raise his voice, didn't uncross his arms, didn't look particularly bothered. "And after I heard about how he ended up on that mountain in the first place, I can't say I blamed the kid for wanting to stay dead."
The accusation in those words was impossible to miss.
Endeavor's flames roared back to life. "You have no right to judge my training methods! I was preparing him to–"
"To what?" Rumi's voice was venomous. "What were you preparing him for, exactly? Because what actually happened is that your kid pushed himself until his own quirk ate him alive. He burned himself up trying to be what you wanted, and you want to stand here and talk about training methods? Seriously?"
"You don't know what you're-"
"ENOUGH!"
All Might's chimed in, his voice carrying absolute authority.
"That's enough. All of you." He looked at Endeavor directly. "Endeavor, your son - Toya, who has been operating under the name Dabi, is in critical condition because he put himself between your youngest son's class and two Nomu that should have killed everyone in that building." All Might paused. "That is the only thing that matters in this hallway right now. Everything else - the blame, reckoning, and explanations - that waits until he's out of that room."
Endeavor looked like he wanted to argue, his massive fists clenching until the leather of his gloves creaked.
Then his eyes landed on the reinforced door of the ICU.
"He is really alive?" the question came out quieter.
Endeavor stood there, processing. For a moment, the mighty Number Two Hero looked completely and utterly lost.
"I want to see him."
"He is in the ICU." Recovery Girl said, emerging from the medical ward at that moment. She looked exhausted. "And even if he weren't, I wouldn't let you in."
"I am his fath-"
"You're the reason he changed his name and spent three years hiding from his own family." Recovery Girl looked up at him, she came up to about his waist, and there was absolutely nothing in her expression that was intimidated by the size difference. "I am his attending physician, and I am telling you, as a medical professional, that the psychological stress of seeing you right now could stop his heart. That's not a figure of speech. I mean it literally."
Endeavor stared at her.
"You want to help your son? Then sit down somewhere over there and stay out of my way until he's stable and conscious. And when he wakes up, he gets to decide if he wants to see you." She held his gaze. "Not you. Him."
Endeavor looked like he had been slapped.
For years, he had believed his eldest son was dead, carried that guilt, buried it beneath his drive to be Number One, but it had always been there.
And now, learning Toya was alive, had been alive this whole time, only to potentially lose him again…
"...I will wait." Endeavor said.
"Old ma–" Shoto started.
"I said I will wait!" Endeavor moved to a chair at the far end of the hall, isolated from the others, and sat down heavily. His flames extinguished completely, leaving him looking strangely diminished in the sterile light. "Until he wakes up... "I will be here."
Nobody argued with him.
The hallway fell back into a silence that was heavier than before - a silence weighted with decades of trauma, unspoken apologies, and the cold reality of a family finally forced to face its own wreckage.
….
.
Inside that room, Dabi's transformation continued.
====
[ARACHNID GENOME] - 15/100%
====
Dabi's cells were in a state of high-speed re-authorship. The Spider DNA was weaving through his double helix, reinforcing the gaps in his genetic code.
The [Super Soldier] serum acted as the perfect catalyst, optimizing the integration, while the deep-tissue effects of [Sun Breathing] provided the hyper-oxygenated environment necessary to fuel this metabolic miracle.
And slowly, impossibly his body was manifesting the one trait it had been denied at birth:
[Heat Resistance]
It wasn't complete immunity but a localized genetic adjustment, with newly densified cell walls beginning to withstand the ultraviolet heat of his own quirk.
He was finally developing the shielding for his own furnace.
====
[ARACHNID GENOME] - 20/100%
====
The percentage climbed.
In the hallway, his family, both by blood and by choice, waited in the dark, all watching to see which version of Toya Todoroki, or Dabi Torino, would emerge from that room.
The night stretched on.
Then, as the integration reached a critical stability point, the transformation paused, allowing the body to settle into its new reality.
.
….
[To be continued…]
★─────⇌•★•⇋─────★
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