The void around Izuku Midoriya shook as the two forces began to make contact, like a couple of great waves smashing into each other. He braced himself, pulling his body back as it tugged towards his vestigial self on the other end of the realm. The identical rooms they occupied slowly approached in a crash course.
He glanced around the room he was in, but only found dark shadows in the shape of those he had took Quirks from. Kota, Mr. Oguro, and two Katsuma's all stood silently with four other blank shades that likely represented the Quirks that Nine had before. They stood completely still, unaware of the chaos surrounding them.
Across the realm were the Vestiges of One for All. Unlike on his side, they were fully aware, more like ghosts than shades. All but his own Vestige was holding their arms up, as if to push back some invisible force. Izuku strained to see it, and Scanning somehow activated within his own body, revealing a great red energy pushing against a multicolored one.
"What's going on?!" Izuku called out to them.
"All for One is trying to merge with One for All!" The First called back, letting out a sigh. "My brother's obsession with my Quirk must have grown so much that even copies without his Vestige contain an imprinted compulsion."
Well, that wasn't good. He looked towards his Vestige, focusing on the red strings connecting it to him. That must be the force drawing the two rooms together. So, each room represented a different Quirk? Izuku turned back to the First. "Can't you keep All for One from merging like when Nine tried?"
"What does it look like we're doing, twerp?!" Daigoro shouted in annoyance.
"The two have already been joined." En added. "When Nine or All for One attempt to take One for All, we can push them out, so to speak. They are removed from the body before grasping at the core of the Quirk. However, All for One was already a part of your body when we returned, and we found ourselves ensnared. We tried our best to prevent an immediate merge by walling the core off, but…"
"I activated Full Cowling and started the merge by flooding One for All through my body, didn't I?" Izuku realized, lowering his head.
"It wasn't your fault. Whatever situation you found yourself in was entirely unpredictable." En assured him.
No. He should have realized something was up when All for One didn't immediately wipe the floor with him. He knew that the Supervillain was toying with him, but he practically handed One for All to him on a silver platter. Shaking his head, he focused on the current predicament.
"So, what is happening exactly, and why is it bad?" Izuku asked, trying to take stock of the situation. Something instinctual told him that the two Quirks combining was a bad idea, but we didn't know why.
"Both Quirks are causing their own issues, but I suppose we can start with All for One. Or more specifically, the ineffectual copy that you ended up with." First glanced around at the shades surrounding Izuku. "As I and my brother told you, that version has a hard limit to the Quirks it can hold. And in a cruel stroke of luck, One for All resulted in that limit finally being exceeded. Unfortunately, All for One doesn't seem to care about that, as One for All takes priority to everything, and your body will destroy itself trying to acclimate us into itself."
"Will the strain really kill me?" He asked worried.
"Quirk Overload is no joke." Hikage answered. "You've seen the Nomu. Those were almost certainly creations of All for One stuffing unfortunate souls with too many Quirks than they could handle. The fact that they could even follow orders is impressive in hindsight. But in this case, it isn't just All for One that is causing the real damage."
"Does this have to do with what All for One said earlier?" Izuku questioned, remembering the man's words about the Fourth User. Hikage nodded in answer.
"If you had gotten any other Quirk besides One for All back, the overload from All for One probably wouldn't be so drastic. But One for All is much stronger than a normal Quirk. Most people can handle a second Quirk for a relatively long time without showing signs of stress. But One for All is so encompassing and powerful that it is causing you to reach critical mass instantaneously." Hikage explained. "It took me eighteen years with One for All for it to finally kill my body, but for you it'll likely take minutes."
So, he needed to increase the space of Quirks he could hold in All for One to be large enough to hold One for All? How could he boost its power? Wait a minute! One of the main abilities of One for All is boosting the users other Quirks!
"Can't One for All strengthen other Quirks? If the two connected more, then maybe All for One would strengthen enough to be able to handle the strain." Izuku suggested hopefully.
Daigoro let out a snort. "Except that One for All would also boost all the Quirks inside of All for One as well, so who knows if there would be enough space then. Besides, your body would almost certainly fall apart before such a process could be completed."
"Oh, that's… great." Izuku growled out. So much for the easy solution. What else was there? He could 'lighten the load', as All for One put it. But the only person around was All for One himself, and he'd just forcefully take One for All instead of making room for it. As terrible as it sounded, that was a worse scenario than the fusion just killing him.
He kept thinking, but it seemed that the answer wouldn't be found within All for One. He couldn't give or take a Quirk, and being able to use multiple Quirks easily wasn't very helpful when said Quirks were the thing that was killing him.
Then maybe the answer was in One for All? It had multiple Quirks within it, after all.
"First!" Izuku shouted, getting the original user's attention. "Tell me as much about One for All as you can."
"Now's not the time for a history lesson Ninth!" The Second chided.
Izuku shook his head. "I don't mean its personal history. I mean its functionality. What can the Quirk do? It's a fusion of Quirks, right?"
He had originally speculated that One for All was a fusion of Quirks back when he begun unlocking the previous User's Quirks. That there was A Quirk that stockpiled power and one that allowed Quirks to be passed down. But the more he thought about it, the more that initial hypothesis seemed off. Certain things just didn't add up.
"You're right." The First said. "As you have likely learned by now, my brother, All for One used the chaos of the Collapse to install himself as the shadow ruler of Japan. I always opposed his actions, but he would always lock me away to prevent me from stopping him. I was weak and sickly, so he eventually forced a Quirk on me that slowly boost up my constitution. I believe he was unaware of how much it would increase my physical strength, or simply believed it would never reach that point. He, no, both of us were unaware that I already had my own Quirk, Bestowal. A Quirk with the ability to give itself to other people. Useless on its own, but when merged with Stockpile it formed the Quirk that eventually evolved into One for All."
Izuku nodded to himself. "I see. I know Nezu thought that the original few users might have been people who originally worked for All for One, so its good to here that it was always a 'Torch of Justice', as All Might put it. There's just one thing I don't quite understand, Yoichi… er, I mean First?"
The First gave him a surprised look. "Where did you…? Ah, right, you saw our memories of the transfer process. The Third used my name then, didn't he?" He gave Izuku a warm smile. "You can use it. What do you not understand?"
"The previous user's Quirks." Izuku answered.
"Really? From what we glimpsed of your memories, you had it spot on." Yoichi said. "The transfer between users also passed on their own Quirk Factor, which slowly grew within the core of One for All until reaching singularity. Once reached, you were able to access our previous Quirks, which had been boosted greatly by the stockpiling effect over time."
Izuku nodded. That is what he had originally speculated. "But that doesn't seem right."
"What… do you mean?" Yoichi faltered for a moment, clearly not used to having someone question the inner workings of his own Quirk.
Izuku let out a sigh, arranging his speculation in his head. "I mean, why haven't the previous user's been able to use their successors Quirks? If your Bestowal passed on the previous users Quirk normally, then they should have been able to use them without reaching some sort of 'singularity'. From what you've explained the holder's Quirks fused into One for All's core, but when does that process happen? The Quirks have clearly been there the entire time as they have been slowly growing stronger by the stockpiling effect, so it's not as if the Quirks suddenly appeared after reaching a certain point. They've always been there, but they were locked off from being accessed due to… something! Have you always been aware that you would eventually reach a point where all your Quirks would be usable?"
The Vestiges all stared at him. They definitely were not ready for such a dissection of their very being, and it took a couple moments for Nana to speak up. "I, uh, was contacted by the Vestiges once and told me that 'it was not yet time'."
"T-That's right." Yoichi confirmed, quickly recovering. "After the Second received One for All and his Quirk Factor was slowly absorbed into the core, I realized that we would eventually reach the singularity-"
"Wait!" Izuku interrupted. "You just said that the Seconds Quirk Factor was absorbed when he received One for All? Are you sure?"
"I am? The current user's Quirk would connect itself to One for All, combining itself in the core while receiving a boost in strength." Yoichi confirmed. "But what does that have to do with the Singularity?"
"It depends." Izuku answered cryptically. "About your original Quirk, Bestowal. Are you able to detect it's Quirk Factor being used, separate from the rest of One for All?"
"Mostly, yes." Yoichi nodded.
"And does it activate at any time other than transferring One for All to a new user?" Izuku asked.
"It hasn't. All my Quirk lets me do is transfer One for All to another person through DNA." Yoichi answered again.
"Then why is a 'Strength Stockpiling' Quirk absorbing other Quirks into itself?" Izuku finally revealed. "As you said, your Bestowal only activated when it was transferred to a new user, and the actual adding of Quirks happened upon being received. And if the effect has been happening as far back of the Second, then that must mean the only other Quirk involved must be responsible."
There was another silence as they all took in Izuku's revelation. Most of the users looked at him in shock, but Yoichi looked like he wanted to bang his head into the crumbling wall of One for All's visualized room.
"What the fuck?" Yoichi swore, turning the other user's heads to him now in bafflement. "How have I never noticed the difference?"
"To be fair, both the giving and receiving happen one after the other." The Third interjected. "I think you can be forgiven for assuming that the processes are connected in some way. Also, the transfer process tends to be rather… chaotic. We all usually have other things on our minds."
"Alright then," En coughed, trying to get everyone focused again. "So, we may have misunderstood Stockpile slightly-"
"Slightly?!" Daigoro interjected.
"Okay, greatly." En rolled his eyes. "But if that's the case, then that leaves the question…"
What was Stockpile, really?
"Let's start with it's effects and try to work back to the cause." Izuku suggested. "It is a stockpiling Quirk of some sort. Quirks grow stronger under its effect, the body is enhanced to superhuman feats, and the stockpiling effect grows more powerful over time. As we just learned, it also absorbs the Quirk Factor of whoever holds it, allowing them to grow as well. But until recently, it didn't allow for the use of these Quirks until reaching some sort of unknown threshold."
"Alright. So, what do we need to figure out to make Stockpile work?" Nana asked.
"Two things stick out. First, what is being stockpiled within the Quirk. Second, what the true nature of the threshold passed was." Izuku explained.
"Seems logical, considering understanding the first is likely required to understand the second." The Second agreed.
"Alright then, any ideas?" The Third asked Izuku and the Vestiges, only to be followed by silence.
Clearly no one had any obvious ideas. Izuku took a step back and looked over the effects. The Quirk obviously didn't stockpile something as ambiguous as 'strength', but what else could you use to describe it? It strengthened everything about someone. Their Quirk and body both. Not to mention that it continued to grow exponentially.
Wait. How did the Stockpile grow? It obviously increased over time, but was that really all there was to it? Izuku turned to the First. "Yoichi, did the growth of One for All ever dramatically shift up or down?"
Yoichi thought for a second. "That's a good question. Actually, One for All has always seemed to stockpile more power and do so faster the longer it was held. It was very slow at first, and it barely grew with the Fourth, despite the time he took to train it by himself."
Hikage sighed. "All that time training as a Hermit, practically wasted…"
Yoichi winced, before continuing. "But once it was given to the Fifth, the speed of its growth continued to grow at a steady rate. I figured the effect was exponential."
"That's certainly odd." Izuku admitted. But what does it mean?
"There's another thing, actually." Yoichi glanced at Izuku's Vestige curiously. "The stockpiling effect actually grinded to a halt when you received it. I thought it was because you reached the singularity or due to the hasty transfer, but the effect slowly started picking up again after about a week. It's barely at the rate of stockpiling that the first few of us had though."
Okay, that is definitely odd.
So, whatever was being stockpiled did fluctuate. It didn't just continue growing exponentially at a fixed rate but changed depending on some sort of factor, even if it continued to grow in general. The Fourth barely had any growth and he lived alone for a long time. The Fifth and beyond were all Pro Heroes. After they received it, it only continued to rise in speed and power… but it all but ceased to grow when he got it.
Right when the Rapture happened.
"Is it related to other people?" Izuku suggested.
"It had a weakened effect when I isolated myself from the world, and all but ceased after the Rapture. An understandable deduction." Hikage admitted. "But then how do you explain the exponential growth and spike? The population of Japan hasn't increased by much between the times of the Fifth and Eighth, yet it continually stockpiled more over time."
They were missing something obvious. Izuku could tell. There was something connected to the population that was being absorbed into One for All. Something that continued to increase in either number or power at a steady rate before disappearing dramatically when the Rapture happened and took everyone with- "Quirks!"
The Vestiges all jolted at his outcry, but Izuku didn't care as he began to speak. "It's Quirks! They were weak at first, and few people had them, but over time they only grew in strength and numbers until the Rapture happened, and they all disappeared!"
"That's…" Daigoro clearly wanted to refute him but found himself struggling.
"That's an interesting theory," The Third finished for him. "But it doesn't quite add up. I think we'd notice the Vestiges being absorbed into the Quirk like us here."
"Oh, it's doesn't absorb the Quirks itself, it just picks up likeminded frequency!" Izuku answered simply, as if it was the most logical thing in the world.
"Frequency? What does frequency have to do with anything?" Nana asked.
"Oh, right! I guess most of you guys weren't around when the paper was released." Izuku smiled, putting a hand to his chin. "I'm referring to Dr. Pleione's Nobel Prize Winning Theory on Extraordinary Frequency in Meta-Humans that was released a few decades ago!"
En raised an eyebrow. "That sounds a bit beyond your level."
"It was challenging, but I managed to figure it out eventually. I mean, it was about Quirks, so I had to figure it out!" Izuku waived off the concern, beginning his own lecture on the topic. "Dr. Pleione discovered that people with Quirks emitted a sort of frequency. A wave of energy that existed on a different level from our original understanding of… everything. She proved that said frequency was naturally released from those with Quirks, and that it continued to grow stronger in later generations of users. It is speculated that this is unknown force is what allows Quirks to do things that would seem beyond typical logic or understanding. A force that allowed the user to redefine their own normal."
The Vestiges all stared in barely held together understanding.
"I see." Yoichi said, clearly not seeing it. "And this ties into Stockpile because…"
"Because Q-Fields are more than just a blank energy force! The frequency emitted by a person is unique, literally shaped by their will, by their feelings." Izuku focused on his eyes in this Vestigial world, activating Scanning within his body again. "That's what I see with Scanning. The lights within others, radiating off them telling me what they are in clear detail."
"Their Q-Fields radiate off of them…" Yoichi began.
"And are absorbed by Stockpile." The Third finished, before sighing. "But that still doesn't answer my question. Why aren't we getting everyone's Quirk then? And how does it boost the user?"
"I have an idea about that." Izuku said, clearly ready to provide an answer already. His mind was now working a mile a minute, safe in his comfort zone of Quirk analysis. "Like I said, Q-Fields are the manifestation of a persons will. Stockpile may absorb the Q-Fields of those nearby, but it's not very efficient. It will only absorb the parts of another person's Q-Field that is like its own core."
"Basically, there's a filter that bounces everything but a set 'idea'. Like a pair of sunglasses keeping out certain strength of UV light." Nana suggested.
Izuku nodded. "In part. But the important part is what that core idea is. That's what decides the kind of Q-Fields being absorbed. Yoichi, what kind of person did you want to be?"
"What kind of person did I want to be?" He parroted back. "That's easy. I wanted to be a Hero like in the comics I used to read. A paragon of justice, who used his incredible power to protect others from injustice."
"And that's what Stockpile began to absorb. The Q-Fields related to an incredible hero who used their power for justice. You see, I believe the stockpiling effect is based on the holder. Since Q-Fields come from within a person, it did more for the holder than absorb small bits that flaked off, but became the source itself. Stockpile would link to the holders Quirk, and their will then became embedded within it. Your Quirk would then become boosted, along with the strength from its original incarnation." Izuku hummed as he concentrated. "The stockpile was probably supposed to be molded entirely by its holder, but with Bestowal allowing you to bring your Vestiges along, it caused a conflict. Outside of the current users Quirk, the only thing you all shared perfectly was the idea that it gave you 'incredible power', resulting in the generic strength boosting that we experienced."
"Are you telling me," The Second began. "That Stockpile only gives the rest of us super strength because the First was a giant comic nerd?!"
"I guess?" Izuku shrugged. "Stockpile would have taken shape to whatever the majority considered their ideal. Your own Quirks were still absorbing relevant Q-Fields after becoming part of the core, they just couldn't manifest. Likely due to some conflict between wills. Stockpile always tried to shape itself into a single power based on the user, but there were multiple ways now that you Vestiges perceived power, causing a tug of war that eventually killed the host."
"This is what caused me to die." Hikage realized. "And why you and the Eighth had no such issues. Without a Q-Field of your own, you both could be molded by One for All's will without clashing against it."
"Alright, suppose your theory is correct." Daigoro said. "I don't understand all the jargon, but basically, we couldn't use other Quirks because of our differences. What changed?"
"Something eventually happened that allowed One for All to access the other Quirks. Something changed in it that made it so that One for All could easily manage the different Quirks stockpiled within and call upon them. Something that did so without causing the typical mental load. Something that was able to keep the will of other Quirks in check." Izuku said ominously, looking at the red strand connecting both versions of him. "And I think it has to do with the second holder of Stockpile."
The Second raised an eyebrow. "What do I have to do with this?"
"Nothing. I wasn't referring to you. You're the second holder of One for All, but Stockpile existed before that." Izuku turned to Yoichi, who seemed to finally understand what he was implying.
"But… He isn't here!" Yoichi insisted.
Izuku shook his head. "He wouldn't be. Nor would the original holder. Without Bestowal, they were unable to keep their will from being overwritten by the next users. But that doesn't change that Stockpile's core would still be molded by them. We don't know what the original holder of the Quirk believed, but the second user…"
Daigoro sputtered. "Wait… are you implying that the reason we can use multiple Quirks is because of-"
"All for One." Yoichi answered, and Izuku nodded.
"He held the Quirk for a time. I don't know how long, but it was likely long enough that Stockpile linked to his Quirk and molded the core. Without Bestowal, and without holding it long enough to shape the core dramatically to something nefarious, there was no Vestige to pass along. Just some part of his Q-Fields signature. The ability to stockpile and use multiple Quirks. It lay like a seed tucked in some corner, growing slowly from any scraps of Q-Fields that happened to make its way into One for All. But due to One for All being molded to fight against All for One, most growth for that ability was slow. But it was inevitable, and it eventually grew to a point that the ability to use multiple Quirks awoken."
"If All for One had awoken, wouldn't you be able to give and take Quirks? I mean, before you actually got All for One?" En asked.
"I think the ability to transfer Quirks imprinted by All for One ended up getting overwritten by Yoichi. They're similar ideas, so that part of the core likely got absorbed." Izuku suggested.
"Do you have any actual proof." Nana asked. "I don't want to doubt you kiddo, but this is a pretty big deal. If you're wrong about it…"
Izuku shook his head. "Don't worry. Now that I can see the Quirks within me, it is simple to prove."
He activated Scanning again, this time focusing purely on his Vestige. He thought the red string connecting them was the pull of All for One trying to absorb One for All. But that is what the force the Vestiges were repelling, as he could see from the two great waves around him. Then what was the red string?
As he focused on the Vestige, the green flames slowly began to part, revealing red within. It moved throughout the body like a nervous system. The lines were thin and faint but grew larger as he approached the Vestige.
"One for All and All for One may be trying to fuse, but it is also trying to assimilate into the imprint of itself within One for All." Izuku revealed.
"Damn. That is one handy Quirk." Daigoro admitted.
"Alright. So, the mystery is solved. How does that prevent you from dying a painful death once the Quirks begin to collide?" The Second asked harshly.
"It… doesn't." Izuku admitted. "Now that we worked out how One for All works, All for One being absorbed should technically be possible. It'll attach itself to the old imprint, taking the stockpiled Quirks with it completely into One for All, meaning that there won't be anymore conflict between multiple Quirks. The only problem is that the process isn't immediate, and I can't stop the overload in the meantime. And if the integration isn't absolutely perfect then I will still be overloaded afterwards."
"What are the chances that it is integrated perfectly?" Nana asked.
"I have no idea. But considering One for All is built upon the rejection of All for One, probably next to nothing." Izuku said hopelessly.
"But then what do we do?" Nana questioned, looking between the other Vestiges in him. "There has to be something we can do, right?"
"Not really. We're literally fighting off All for One right now." Second pointed out. "We can stop and let the fusion continue, but as Ninth said, his body would probably break apart entirely before the two can connect properly."
Izuku took a deep breath. "…We have to try. I'll do it."
"No!" Nana said, like a lecturing mother. "I won't let you do it."
"We don't have time for this, Seventh." The Third said. "There's only two ways this can end. And Ninth isn't the type to just take his fate lying down. None of us are."
"I…" Nana looked ready to fight the point, but she eventually relented. "I know. I just wish there was another way."
"Don't worry Nana. I have a plan." Izuku said, although admittedly it wasn't a very good one.
He still had Overclock, Scanning and two copies of Cell Activation. If he tried to use them all, he might be able to speed up the process while also keeping his body healed enough to not keel over until it completed. But he still had no way to guaranteed that the fusion would complete. Scanning would let him observe the process, but he had no way to directly manipulate it.
No Quirk he had could directly modify the body like that.
"Alright Ninth. We're ready to drop our resistance on your mark." Yoichi eventually said, and Izuku steeled his eyes.
"Alright… on three." Izuku began, reaching for the Quirks on his side. "One. Two. Thr-"
The entire realm shook again, and Izuku glanced around quickly, checking if the Vestiges had dropped their resistance early. They hadn't, but there was still an overwhelming pressure that began to push down around him.
"What's happening?" Izuku asked, as Yoichi stared up at a point in the void above.
"I guess my brother got tired of waiting."
A hole appeared in the void. From that void poured out an insidious red energy. All for One. The real one.
"I guess he decided to take One for All now in case we decided to kill ourselves out of spite." The Second spat out as the red energy began to fill the void in a wave.
"Does he really think he can take it this time? It hardly worked the last couple times." Daigoro asked.
As if to answer The Fifth's question, a double helix strand of red energy also began to poke into the void. It proceeded towards them, and Izuku activated Scanning to try and identify the Quirk. He could tell it was different from All for One, but the answer he received surprised him.
"That Quirk!" Izuku stared up at the approaching swirls in amazement. It was some form of genetic manipulation. Very likely the one Nezu mentioned seeing All for One use earlier. It seemed the version of All for One Kagome received also had it. With Scanning active, he could even see what it was trying to do.
"All for One is planning to use Genetic Manipulation to fuse One for All and All for One!" Izuku said.
"We can't defend against that! We can only block his Vestiges connection to us through All for One!" Yoichi cried out to Izuku. "We can't do anything about him literally ripping it from the body with some other Quirk."
This wasn't good. If Genetic Manipulation reached his Vestige, it would rip One for All's core out of it and fuse it with All for One. There was no way to change the command. It would reach through his entire body to ensure that the brother's Quirks are put back together.
"Wait a minute." Izuku stopped for a moment. The command that Genetic Manipulation had was to fuse One for All into All for One. But there were two All for One's currently. The one he had, and the one invading his body. Genetic Manipulation was connected to the Villains consciousness so it would normally head to that one. But…
"Yoichi! I have a really crazy idea!" Izuku shouted.
"You seem to come up with a lot of those. What do you have this time?" Yoichi asked.
"I need you to keep All for One out of One for All as much as possible!" Izuku said.
Yoichi looked up at the slowly encroaching force of All for One. "It won't stop that second Quirk of his though. And we can only stop one version of All for One at a time. If we focus on my brother, then the fusion will begin in earnest."
Izuku let out a thumbs up. "Good! That's exactly what I need."
"Good?!" Yoichi gave him a crazy look. "What the hell are you planning?"
"That second Quirk is trying to fuse All for One and One for All. I say we give it exactly what it is looking for." Izuku said with a cocky smile.
"You are absolutely insane… and I love it!" Daigoro cried out.
All the other Vestiges either nodded in agreement or shrugged in disbelief. Yoichi just chuckled. "It's certainly a plan. On three?"
Izuku nodded, mentally gripping the red strings connecting the All for One in him and his Vestige's core.
"One."
"Two."
"Three!"
The Vestiges all shifted, and the wave of One for All's energy shot up towards the hole that All for One had created. It smashed into the red energy, pushing it almost all the way back through the hole. But Genetic Manipulation approached unabated.
The original wave of All for One from himself now found little resistance, and swarmed towards One for All, taking the room he was in with him. It sped forward, and Izuku lined himself up with his Vestige. The second both rooms slammed into each other, they exploded apart, leaving the two crumbling structures a pile of rubble around them.
The Vestiges and shades all floated there in the ruins, and he reached out and grabbed his burning green shade. It reacted immediately, eyes lighting up red as it began to consume him.
The Vestige lost shape as emerald flames ran up his arm and into his veins. He fell to his knees as it spread across his body like he had been covered in gasoline. It didn't literally burn though, instead feeling like his own power was going to explode out from within him. It was like he was about to use 100% of One for All across his entire body and couldn't shut it off.
"Izuku!" Nana cried out in concern, but she couldn't help him now. He was on his own.
Both One for All and All for One ram through his entire body, trying to figure out how to fuse. The power ran wild as it kept trying to adjust to the overwhelming power. All for One kept trying and failing to bring One for All into itself. Meanwhile One for All was both trying to absorb the holders current Quirk into the core, while rejecting One for All due to its nature. The Quirks were functioning like an ouroboros eating its own tail, unable to cease.
Eventually an Equilibrium would be reached. Enough of the two Quirks cannibalized by each other to fuse properly. But it would kill him long before then.
He called upon Cell Activation to heal his body and Overclock to speed up the process. Red hot irons stabbed into his head as the shades came forward and activated, but he needed to hold out long enough the two Quirks to connect. It didn't matter if the fusion was tearing him apart. If they were close enough, his plan would work.
The green fire of One for All began to seep into him, stopping burning without and instead within. The pain got even worse, but it meant that the two were connecting on some level. He could see with Scanning the red lines of All for One pulsing in his veins, as the flames of One for All bulged in his skin, looking for release.
Looking up, Izuku saw the approaching double-helix. Using all his remaining strength, he struggled reaching both hands up. They each approached a different strand, and Izuku gulped.
'This is the moment of truth.'
All for One's will would normally overwrite anything that his victim could do to resist. But One for All's Vestiges were currently keeping him out, leaving the Genetic Manipulation with a simple command instead of his conscious guidance.
Meaning if the Quirk received guidance from a stronger will with the same goal, it should follow it.
He grabbed onto Genetic Manipulation, and the Quirk froze. It seemed to be processing what it had contacted, reading his Quirk curiously. After a moment, it found what it was looking for and sped into his body.
Izuku could feel what was like his body unravelling and repairing itself at a rapid pace. He couldn't process exactly what was happening, but his body was frozen stiff by Genetic Manipulation's effect. But staring at the strands of it that led out to All for One, he could see that nothing was leaving him.
Around him, the two destroyed rooms began to form back together. Brick by brick the structure combined back into a new shape. The tattered room from before suddenly came together clearly, forming something that looked just like his bedroom.
The walls slowly began to form posters, each representing one of the previous holders and the shades of All for One. Their history embedded within the Quirk. Something around him began to glow, and he looked over to see one of his notebooks, shining with a bright light. The pain of the fusion and struggle of the Vestiges forgotten, he stumbled over to the notebook and flipped to the first page.
'Quirk #1: Stockpile'
Words began to form on the page, being printed from a red double helix line coming from his hands. They detailed everything he had learned about the Quirk in perfect detail. The book then flipped to the next page to create a new entry.
'Quirk#2: All for One'
It filled in even more info as it continued the recording process. It added Bestowal, Gearshift, Fa Jin, and all the others. Izuku eventually realized what was going on.
'Genetic Manipulation is organizing all of the Quirks inside me.' He realized. The notebook must be his own way of visualizing the stored Quirks being written into him. As it finished recording the last Quirk the book snapped shut, and the entire world became silent. Izuku stared down at the cover and noticed one last thing that needed to be added.
'Izuku Midoriya - Quirk: '
He thought about it for a moment. This was a different Quirk than both One for All and All for One. It needed a new name. Something that encapsulated the spirit of both. After a couple seconds contemplation, he decided, and the red lines of Genetic Manipulation etched it onto the cover for him.
The fire inside him could still be felt, but it no longer burned him. His veins pulsed, but now in beat with his heart. He looked up to see the two strands of Genetic Manipulation dissipating as their objective was complete. He looked over at the Vestiges, who all stared back at him. He gave them a nod and they returned the gesture. They could feel that it was done.
Izuku reached deep within himself, grabbing the core of his Quirk. It wasn't the same as before, but the wellspring of power was still there. He grabbed at it, pushing it through his whole body. The fire spread out, engulfing him in a warmth that was comforting to him. He reached up a hand towards the hole formed by All for One and pushed.
All for One smirked as he felt the familiar resistance of his brother push against his attempts to steal One for All. It was nostalgic, in a way. But this would be the last time such a conflict would happen.
Midoriya's Izuku's body was literally breaking apart at the seams. His skin splitting and bones breaking as the power exploded out of him. There would be no surviving for him once this was done.
He had also pushed in Genetic Manipulation separately from All for One, using Controller to order the Quirk to fuse his and his brothers Quirk. It was a relatively simple command, but once it connected to One for All, he would be able to assert more direct control. The Quirk would grab One for All with one end, then he'd add his All for One to the other, and he would drag it up and out of the current holder. It was too easy!
Which is why he should have realized something was wrong when no genetic information was being taken from the ninth holder, despite the red double-helix of Genetic Manipulation running across it.
As the resistance from his brother continued, he noticed Izuku Midoriya's body slowly cease to convulse, the Quirks within no longer colliding. He had believed it was because he was removing the cause of such conflict. But he slowly began to realize that something else was going on when Genetic Manipulation sent a command that it had completed its task and left the body, but no Quirk came with it.
"What?!" He focused on the boy, only to notice the resistance from within One for All grow. It hadn't been removed at all! But then why did Genetic Manipulation say it was complete? He tried to push Genetic Manipulation in again, only for Midoriya's eyes to open with blazing irises.
He jumped away just in time for the area around Midoriya to change. One for All exploded out, and his body flexed with power. His eyes flared, hair standing on end, glowing a brilliant cyan. Raw power didn't spark across his body but ran across it like an aura of fire. The boy's body healed over in an instant. His wounds glowed as they sealed themselves and his bones reset themselves. The scars remained, but the damage was gone.
Eventually the raw energy emanating from Midoriya lowered, his body only flowing with half the power as before. The glow and aura dimmed, but remained almost blinding in a way he couldn't describe.
"How are you even alive?!" All for One shouted out to the child in front of him. "How do you still have One for All?! I should have it now, damn you!"
Maybe he just needed to apply a little more force. He raised a hand and prepared to call upon-
"Radio Waves. Air Cannon. Heavy Payload. Scatter." Izuku said to himself quietly, eyes flashing.
'This Brat!' All for One grimaced. The boy somehow knew what Quirks he had wanted to use before even activating them! But it wouldn't change his fate. The power coalesced in his hand, before exploding out in six different beams. They approached from various directions, ensuring the boy had no space to dodge now. "Die!"
The beams all converged on their target and exploded in a glorious wave of energy. But as the dust faded, he found his target still standing there unmoved. Surrounding Midoriya were six golden discs, affixed at the exact points that the beams he had shot out. Midoriya raised a hand and the discs all converged on it, stacking on top of each other and pointed directly at All for One.
"Release."
An explosive blast of air shot out that dwarfed even Air Cannon when boosted by his other Quirks. All for One was launched across the domed room at sonic speeds, slamming into the wall of pods in a crash. He tried to pick himself up, only to see a Hydra head speeding towards him.
He easily dodged, only to find a dozen more approaching. They were as fast as a hail of bullets, and All for One narrowly dodged them as he jumped towards Midoriya. The Hydra's dissipated as he flew through the air at him, and All for One prepared another blast, only for his opponent to vanish.
'Where-?' All for One only had a moment to think before something slammed into him with the force of a bomb. He turned to look, only to find himself being hit in a new direction, and again, and again. Eventually the flurry of attacks ceased, and he returned to his senses long enough to find Midoriya.
Midoriya stood in a pose he hadn't seen in decades. A purple energy formed from both hands similar to the Laser Bullet from before, cupped together at his side. Red energy from Fa Jin then pooled from his arms into the energy, coloring it a dark magenta. He pushed his hands forward with a shout, and a beam streaked across the space into All for One.
"Grah!" All for One cried as the energy slammed into his discombobulated body, and he crumpled back to the ground in a heap. As Super-Regeneration activated and he got to his feet, he stared forward with pure hatred. "What… What did you do to my brother's Quirk?!"
Izuku just smirked. "I did exactly what you wanted. I fused both of your Quirks, though I never would have been able to get it so perfect without your help."
Genetic Manipulation! The brat had somehow tricked the command while he was distracted with his brother. To think that he was being undone by this alien's power again! He let out a maddening chuckle as he stood back to his full height. "Oh well. At least I know that it is possible for our Quirks to be properly fused using Genetic Manipulation. Now, come back over here and give me One for All!"
"One for All?" Izuku quirked an eyebrow. "I don't have One for All anymore. I don't have All for One either. Genetic Manipulation put them together into an entirely new Quirk."
All for One let out a huff. "Oh? And what Quirk would that be?"
"I think you'd find the name rather self explanatory. It's a Quirk that can take the wishes of all around and entrust them to one, who is then strengthened by those shared wishes." Izuku explained, as the energy around him grew to its full power. "I've decided to call it…"
Next Chapter: All in One!