Izuku felt One for All flood into his arm at his upper safe limit, ten percent. As he powered up, Izuku felt One for All swell slightly, and his percentage upped itself slightly. It felt like when Izuku would test out limits in training, and that familiarity helped him recognize that his safe limit had likely increased to eleven percent somewhere during the few days of camp. He'd been turning One for All on constantly during his training in order to contact the vestiges, and even if that hadn't worked, it had gotten his body more in tune with the power of One for All. With that knowledge, Izuku evened the power out across his whole body, powering up Full Cowling style at eleven percent.
All for One didn't have time to react, as he'd had his guard lowered for his approach to Izuku, clearly expecting him to agree to join his father's side. Well, that wasn't happening. Izuku, as the power evened out, threw out a quick punch at All for One, getting him right where his nose should have been, but wasn't. The hit made his head rock back, and All for One's focus must have slipped because of it, lessening the power of the telekinesis Quirk that he'd had Izuku held in.
Izuku fell to the floor, and cradled his messed up arm in his good one while he worked Blackwhip around it in the shape of a cast and sling. It wasn't exact, just a chunk of Blackwhip and a few strands going around to hold it up, but it would work for now. He was no Pixie-Bob, but he could do this. Izuku then used his speed to back as far away from All for One as he could, feeling the wall stop him in what felt like an instant, but was likely a few dozen meters by how far away All for One looked now.
"Izuku, don't be like this. Just think about what we could achieve together. With your power, you could be more powerful than even me!" All for One tried, but Izuku wasn't hearing any of what he had to say.
"I don't care about power. I'm never going to help you. If you don't let me leave, this is gonna get messy," Izuku said, channeling his best impression of Bakugo into his threat.
"You've got no idea about messy, Izuku. Rethink this. If you turn me down, I won't spare you, even if you are my son," All for One said.
"I'm not your son, I'm your objective. You're just an old man who's overstayed his welcome," Izuku said, putting up his good hand to fight.
All for One stood to his full height once again, showing Izuku just how outmatched he was. It was true that Izuku still didn't have Smokescreen, Fa Jin or whatever the hell the second user's Quirk was, and that he was still at eleven percent of One for All's base power, but he couldn't just lay down and die, or be turned to the Villains' side. He still had to save Tenko. He still had to tell Aizawa and Mic that Shirakumo was alive, in a way. He still had to get back to Ochako, Hitoshi and Tsu. He still had to mend his relationship with Bakugo. He still had to tell All Might just how much he meant to him. He had to see his mother, knowing what he knew now. He had to do so many things, and this symbol of a bygone era wasn't going to mess that up for Izuku. Not now, not ever.
Izuku prepared for some kind of attack, but All for One simply stood there. Watching him, Izuku noticed that it was because of the wires. He could move further than what he already had because he was hooked up to those machines. He could hear them better now, without the pain and the conversation with All for One taking up his focus. They were medical in nature, an EKG machine, what looked like an artificial lung, stuff like that. He couldn't move too far away from it or he'd start to succumb to the injuries he clearly still carried from his fight with All Might. That gave Izuku both an advantage and a disadvantage. He wasn't very good at ranged attacks, though he had an idea that might work, but it meant that All for One couldn't get him with his hands. With how many Quirks the Villain had to have, though, that didn't mean much.
"You want to play this game? Fine, have it your way. Air Cannon," All for One said, holding his hands out in front of them in a clearly aggressive manner, even though it tugged slightly on the wires that snaked into his skin.
Izuku felt Danger Sense ring in his head, and immediately threw up a Blackwhip Shield, though it was smaller and weaker due to him only having one hand to form it with. He barely had time to curse his luck under his breath when a massive force swept him into the air and slammed him into the brick wall, breaking his concentration and forcing the shield to dissipate. Izuku groaned as he got his bearings, and saw that All for One hadn't moved, confirming that he had ways to hurt Izuku from afar. He slid himself up along the wall and stood back up, reaffirming his control of One for All and getting ready for another hit, though his back and head did throb from the attack.
"See what I can do with just one attack, from just one Quirk? You could have that. You could be a god, Izuku. You could do everything you ever wanted. You could get back at Bakugo after everything he put you through. Doesn't that sound nice?" All for One said, his voice not matching the way his frown tugged at his scars.
"That's the thing, All for One. I don't want revenge. I'm not in this for power, or to let off some steam. I want to help people, and take down people like you who only want to destroy and hurt others! I'm not backing down," Izuku said, letting Blackwhip run down his arms and legs to form Dark Cowling on his good limbs and pumping his percentage up to thirteen percent, reasoning that if his safe limit had been raised, his limit with Dark Cowling must have gone up, too.
"Be that as it may, I don't want to hurt you, Izuku. I want you to join me, and if you won't do that of your own free will, then I suppose I'll have to make you," All for One said, priming himself once again to use the same attack.
This time, Izuku was ready for it. Long before the tingling of Danger Sense in his head warned him that All for One was going to attack, Izuku had begun piling up dense wads of Blackwhip along his limbs, and as soon as he felt the telltale warning in his brain, Izuku sent those wads of the Quirk out and around himself to form a dome with three of his limbs to the best of his ability, fortifying them with One for All's power as best he could and hunkering down on the ground.
Izuku felt it as the blast impacted the Blackwhip Shield and was rendered inert by the thickness of the protective dome. Izuku wished that he could just stay in his bubble and not fight the most powerful man in Japan, but here he was. Izuku got started on his plan, building up the charge of One for All in his body as he slowly raised the percentage and kept all that energy inside his body, just like he had during his final exam. As he did, All for One laughed.
"Do you think that overcharging yourself will bear any good results? You'll just burn out, Izuku. Don't waste your power like this," All for One said, laughing all the while.
"Don't you waste your breath trying to reason with me now. You blew it," Izuku said, buying himself time to reach one hundred percent charge on a move he'd decided to call Tempest. It was like a storm of energy inside him by the end, and so he'd decided to theme the move after it. There was even lightning!
When Izuku hit one hundred percent, he raised his arm and pointed his hand at All for One. He allowed the lightning of Full Cowling to surge around him, almost uncontrollable and searing hot now that he'd hit full charge. He smirked, feeling himself become satisfied at how he'd been able to manage it this far. Once he was at full charge, Izuku began to take the energy pulsing in and around him and pack it into his singular good hand. It began to cramp up and the energy was so hot that it felt like he was cooking from his hand to his elbow, but this would be worth it. It would destroy his life support, and force him to retreat, because he surely had backups of the equipment that kept him alive. He'd win if he could get this one shot off on target. He had this.
It almost seemed like the skin on Izuku's hand was a shimmering white for a moment, but he knew that it was just the intense amounts of energy that was contained in his hand and lower arm at that moment that made it seem that way. After that split second flash of light, a green surge of lightning pulsed from him and raced in a jagged line toward the life support equipment, to where he changed the aim of his hand at the last moment. A heartbeat later, it was dark.
As he was enveloped in darkness, Izuku shut off Full Cowling, knowing that it generated at least a little bit of light and that All for One could use that to find him. He still wasn't sure how the man saw without eyes, probably some kind of Quirk, but shutting off Full Cowling surely couldn't hurt his chances. It didn't seem like All for One was trying to hurt him any more than when they'd started, just trying to get through to him and turn Izuku to his side, which was never going to work, so he was reasonably fine to shut down One for All for a moment to catch his breath as his arm cooled down after the casual use of Tempest, what was probably his most powerful attack at that moment, having taken out Bakugo in one hit and all.
As soon as it was dark, Izuku heard gagging and choking noises. He decided that he didn't want to hang around to find out if All for One was still capable of attacking and started booking it to where he thought he'd seen a door to his left. Izuku hit a wall soon enough, and figured that he didn't have a lot of time before All for One either got himself back on his life support, or just ignored it and chased after him with his sensory Quirks, probably able to see in the dark. Izuku chose life. So, he powered up One for All to fifteen percent and then pumped Blackwhip out over his arm to form Dark Cowling and went for it, bashing the wall in with everything he had.
As it turned out, Izuku didn't have to try that hard to bust through the wall, as it crumbled with ease under his power. The brand new hole in the wall the size of a car led him into a hallway, and Izuku wasn't one to ignore an opportunity. He ran into the hallway, and saw that he could go one of two ways. To Izuku's left was a staircase that probably meant that he was underground, or at least in a storied building. To his right was a series of doors that seemed like steel or iron, but either way they were reinforced. Izuku chose the staircase.
Izuku pushed himself to power up to eleven percent Full Cowling in record time and ran. He sprinted through the hall as he heard the choking and sputtering of All for One behind him begin to form into words and orders to stay. Running was slightly jostling Izuku's arm, but he just pushed himself faster, reaching the small alcove in the hall in a second or two. He looked up to see that the staircase just went up and up, and he couldn't see the top if it was even anywhere within sight.
Steeling himself, Izuku crouched down. He coiled the muscles in his legs and his torso, readying himself to leap. He called on Float, and felt its comforting presence, like a blanket that told him everything would be okay. Izuku didn't know how much he believed that, but he'd find out whether or not he wanted to. Izuku straightened out his legs and jumped, feeling his strength and Float carry him up past the levels where the stairs evened out to platforms that led to doors.
It was a miracle that Izuku managed to get to the top of the staircase in one leap. He'd started to stall in the air, and had been ready to use Blackwhip to pull himself along, but he rose above the railing on the top level and released Float, allowing himself to touch down on the platform in front of the door. It wasn't labeled, so he couldn't get any clue about what he was walking into, but he was pushing on anyway.
Izuku was about to go through the door, his hand beginning to push the handle to open it, when he heard a crash from below. Feeling a passive warning from Danger Sense, a kind of low buzzing in his head that meant that danger was near but not necessarily coming for him, Izuku turned back to the stairs. He hesitantly stepped toward the railing and looked out over it to peer down into the depths, only to see All for One clawing his way up the middle much like the way Izuku had Floated up the gap between flights, only much more destructive. It looked like All for One had manifested more arms and hands for himself in order to climb faster, which unnerved Izuku only a tiny bit less than the dark, featureless mask that the man now wore, likely to support him away from his machines. Izuku was startled by this, and turned to sprint through the door, property damage be damned.
He broke through the door easily with Full Cowling active, but soon found himself in a predicament. Izuku was in a room with about a dozen tanks, and sticking out the top of them all were brains. Izuku didn't have time to be disgusted, as he distantly realized that they were all probably in-production Nomu, and began running through the room looking for a place to hide. Izuku knew that All for One was going to be there in a few moments, so he needed a place right that second.
As Izuku panicked, he wandered over to a corner, wedged between two Nomu tanks, and crawled inside, no small task for someone with one good arm. He made himself as small as possible, shutting off One for All to minimize himself even more. Izuku cowered, which would not be a good look for him if Bakugo caught him doing so, but he couldn't bring himself to really care at the moment. All for One was going to find him, and he needed to be unseen, so this was as good as it was going to get. Izuku started silently wondering if One for All's second user had a convenient invisibility Quirk, or if Blackwhip could help him blend in with the shadows, or if he should just give up.
Just then, as he was thinking about the different Quirks he could've possibly used to hide, a thin wisp of something was swept away from Izuku's hand. With the room practically falling apart prematurely due to All for One's rapid, violent approach, he barely saw it, but was able to catch it with the little amount of light that was in the room. It was a faint puff of smoke that had come from Izuku's palm, but just for that moment where he'd been panicking about hiding. It hit Izuku like a truck that there was a Quirk that was built exactly for stealth operations like this one, though this wasn't an operation so much as an attempt at not getting squished like a bug.
This must have been Smokescreen. Izuku almost smiled, but the crashing of All for One getting closer kept him from celebrating too early. With a vague idea of how to use this power, Izuku willed that same feeling of anxiety and wanting to be unseen back into the forefront of his mind, and lo and behold, the smoke began slowly billowing up from his hand. Izuku noticed that it was sort of slow for what he needed, so fired up One for All for a brief moment and pushed, going full blast with Smokescreen in a way that En would surely approve of. A thick cloud of smoke burst from his hand, and Izuku was completely smothered by it, but was otherwise unharmed and unhindered in things like breathing and his body heat, like he'd theorized all the way back before final exams.
Izuku didn't have time to celebrate his unlocking this new Quirk, however, as a loud crash came from the area near the door, and the sound of rubble falling to the ground sounded out as panting filled the room. All for One must have still been recovering from his brief stint without his life support. He also must have taken down the wall instead of walking through the door like a normal person, but Izuku didn't truly expect him to have manners when he'd put him in a situation where he could easily die or suffer irreparable damage.
The sound of boots clunking on the ground drew closer, and Izuku felt Danger Sense flare up as All for One must have gotten a bit closer. Izuku couldn't see through the mist, which was a major downside to Smokescreen, but he had something better than sight that always worked. He'd be able to sense All for One wherever he went now, and whatever sensory Quirks he used may not have helped him any better than regular eyes. Izuku held his breath when Danger Sense told him All for One was getting closer, not wanting to give himself away so easily.
The sound of boots walking along the floor was soon silenced, however, and Danger Sense stopped giving active feedback on All for One's location, almost as if he'd stopped moving in the middle of the room.
"What in the world is—" All for One said, abruptly cutting himself off mid-sentence. When he'd spoken, he'd sounded like the few times he'd heard hearing impaired people talk, like he couldn't … hear what he was saying. Huh.
Izuku's mind began racing with this information. Could he no longer hear? Could he still 'see'? Izuku wasn't sure if he'd gotten a good look at where All for One's ears should've been, so he couldn't say for certain if he had them or not, but he was willing to bet that he didn't, and that he used Quirks to compensate for at least two of his senses. If he couldn't hear anymore, and he'd only experienced that effect while in the smoke that Smokescreen had created, then could it be reasonable to say that Smokescreen's smoke suppressed sensory Quirks, either while the user of said Quirk was inside, or simply that sensory Quirks couldn't penetrate the cloud that Smokescreen generated? It was reasonable, as Smokescreen had been charging inside One for All's core for a few generations now, that it could be changed to outright negate the ability to sense through the mist instead of simply blocking vision. That would be incredible if it was correct, but that was just a hypothesis at that moment. Izuku needed to focus on getting out of there before he could test anything.
As Danger Sense was still on and giving Izuku a general location for All for One, he was able to confirm that the user was exempt from the possible sensory Quirk suppressing effects. So, with that in mind, Izuku summoned a glob of Blackwhip and launched it across the room to where he'd seen some beakers and tubes, or something like that, to break them. He threw the end of the whip across the room and, after a moment, heard a cacophony of glass smashing and falling to the ground, at which he recalled his Blackwhip.
All for One seemed to falter in his spot in the middle of the room, almost like he'd lost his balance, and didn't react at all to the loud breaking of glass that he surely should have heard if his senses were as normal. This didn't give Izuku a solid conclusion, but did let him know that he could keep either himself or All for One inside the Smokescreen at any given time, and he could escape. That was enough for now. So, Izuku slowly stood up and got into a position where he could start a sprint from.
Izuku readied himself, and then fired up One for All. He cranked up his percentage to eleven percent and began to blast Smokescreen out of his good hand. As even more smoke filled the room, completely obscuring everything except for the pings from Danger Sense telling him where All for One was, Izuku figured out his game plan. He'd barrel through the roof and fly away, hopefully learn where exactly he was, and run over to UA as fast as he could. It had been days, judging by what he'd learned in the bar, so there had to be people looking for him. He could just get found somewhere in whatever prefecture he was in right now. Perfect.
As soon as Izuku was about to leap up at the roof and break through it, however, a large rush of air and rubble from that same roof rained down on the room, causing All for One, still inside the Smokescreen, to stumble. The rush of air began to violently throw his smoke around, and Izuku began to panic, thinking that he'd been caught and that All for One was going to be able to find him because of this. But, as the Smokescreen did clear, Izuku saw that the thing that had busted the roof in was a foot. A large one at that, larger than a car. It was in a costume, and one he recognized as Mt Lady's purple and beige outfit. He had a chance if other Heroes had come!
Knowing that he had his chance while All for One was likely still stunned, Izuku crouched and put his all into jumping toward the massive hole in the side of the room that Mt Lady had just made. He moved through the air in a flash, and Izuku briefly wondered if he'd put too much power into the jump to be safe. His legs felt fine, though, during the moment he flew through the air, so Izuku guessed that he was fine. He was much more worried about his arm, anyway.
Izuku soon hit Mt Lady, the Hero having enlarged to kick down the roof and not having shrunk back down yet. He hit her right in the stomach, and budged her slightly before she must have realized what had happened, because she cursed him out briefly before the two met eyes and she gasped as she must have recognized him. Izuku let himself fall to the ground outside whatever building he'd just been inside, seeing on the way down that he was on a street in some city. When Izuku hit the ground, he landed safely, if a bit roughly for his arm, and looked around.
A collection of police and Heroes, including Mt Lady, who was still reeling from their collision, Best Jeanist, the number four ranked Hero, Gang Orca, the tenth top Hero, and Tiger. Izuku sucked in a surprised breath at seeing Tiger, as the bulky man and Izuku locked eyes and both hesitated for a moment. Izuku had gone against Tiger's orders by giving himself into the Vanguard, getting him in this situation in the first place. He'd tried to fight for Izuku, but had ultimately not convinced him to back down and let the able fight their fight. Izuku wasn't sure where he stood with Tiger now.
"Midoriya! You're okay," Tiger yelled, in his typically angry tone, but ran over and wrapped him in a tight hug anyway. Izuku reciprocated, mainly out of shock.
"Everyone needs to get far away," Izuku mumbled, the shock of being near so many top ranked, famous Heroes still getting to him a little. When he truly realized how dangerous so many great Quirks being this close to All for One was, Izuku became more frantic and adamant. "Everyone needs to get far away from here!" he screamed.
"What's going on?" Best Jeanist asked, approaching with Gang Orca.
"You need to evacuate and call All Might! An S Rank Villain is in there, and he's angry!" Izuku said, spinning around to keep the new entrance to the building in his view. If All for One got out and started wreaking havoc, nobody but All Might could stop him.
"We need to get him to a hospital. Just look at him," Gang Orca said, completely ignoring Izuku's warnings.
Izuku, looking at the other Heroes, realized that they must think he's just delirious from the days of captivity, the torture, the dehydration, the starvation, the exhaustion, both physical and Quirked, and every other terrible thing that'd happened to him that week. To an extent, they were right, but he wasn't joking around with this. If these Heroes didn't evacuate right now, Quirks were at risk of being stolen and added to the arsenal of the most dangerous criminal in Japan, and maybe the world. Just when he was about to tell them this, Danger Sense went off and Izuku whipped back around to see that the masked form of All for One was standing up on top of the rubble that was once the outer wall of his complex.
"Well, I didn't know we had guests. So nice of you to invite some appetizers," All for One said, his voice sending a shiver down Izuku's spine.
"Sir, get down from there. We're conducting official Hero business and we need you to clear out," one of the police officers yelled. Izuku almost screamed at him for being so oblivious.
Danger Sense, where it had been a low, hesitant hum in the back of Izuku's head, became a roaring warning to movemovemovemovenow . Izuku wasn't one to disobey Danger Sense, and immediately began pooling Blackwhip in his hands for a massive shield, as he'd seen what All for One's attacks were like, even when he was holding back. He also prepared to call on Smokescreen again as a Plan B, as he could envelop them all in it and hide from All for One until someone called All Might. That might not work, Izuku realized, because All for One was a keen analyst himself, and would likely see through his use of Smokescreen and just target the blindspot in his senses. Well, he tried.
"Somebody call All Might already!" Izuku said, his whole body tensing as All for One readied his hands for an attack.
All for One stepped out from the rubble, but didn't descend. Instead, he stepped out onto the air itself and stayed there, likely using some kind of levitation Quirk to keep himself airborne. As he did, Izuku saw his hands swell in size, and finally threw his hands out in front of himself to set up his shield. All for One's arms crackled with the same kind of red lightning he'd had in the vestige realm, and a burst of air was released from his hands, shooting out at the ground below them.
Izuku braced for impact, and readied himself for the blast before a numbing wave of force hit him and everything went black.