"Kacchan!" - Speech

'Dammit!' - Thoughts

"I AM HERE!" - All Might Speech

"Detroit Smash!" - Special Technique Usage

Beta'd by BigCC

Chapter 2: Sludge Villain, Second Shot

On Top of a Nearby Roof, Musutafu

Yagi Toshinori let out a deep huff of breath as his body shrunk, shrivelling down to his weakened, skeletal form. 'Dear god, I feel so pathetic like this.' the hero thought ruefully as he leaned against the rails of the roof to try and catch his breath. A few measly hours, that was all he could do to maintain his heroic form, and it was getting harder with each passing day to keep it up for that long.

Oh how the mighty had fallen indeed. All for One was probably laughing at his expense, this kind of slow withering death would have probably tickled that most despicable of villains' fancy.

'Nighteye...I should have listened to you earlier.' he thought tiredly. His old sidekick, Sir Nighteye, had literally begged him to retire after the last battle against All For One, but he'd refused. Even injured as he was, he couldn't ignore weight of the Symbol of Peace that rested his shoulders, couldn't ignore the needs of the people relying on him to make them feel safe. He had to keep fighting until a new Symbol was ready to emerge, lest the innocents of the world suffer from the anarchy that would likely follow his retirement.

At first his 'time limit' had been manageable, he could handle going at full strength for half the day, before he'd be reduced to about half-strength for the remainder. Annoying, but manageable. Now, five years later, and he was lucky if he could manage three and a half hours and he was nearly completely powerless until he could start to recover.

Double-checking the bottles where the Sludge Villain was currently confined within, the Number One Hero had to chuckle at the awe and clear hero-worship that the boy, Midoriya Izuku, had shown towards him back there. The youngster had done surprisingly well against a tricky and dangerous opponent until he arrived. He hadn't been lying when he'd said that most Junior-High kids wouldn't have been able to fight a villain for any great length of time.

'Young Midoriya has a powerful Quirk and a strong desire to be a hero. I shall have to keep an eye out for him at U.A. High.' Toshinori thought with a tired smile.

Nezu had finally managed to convince him to take up the Foundational Heroic Studies at U.A. as a way to scout out someone capable of becoming the ninth bearer of his Quirk, [One for All]. Initially, he had always envisioned passing his power down to another close combatant like himself and his own Master, Nana Shimura, had been, but seeing such a surprisingly potent Quirk in the hands of a noble youngster like Young Midoriya had reminded him that [One for All] was not merely a Quirk that boosted one's physical strength.

Gran Torino, Nana's old partner and the man who had trained him after his Master's passing, had mentioned that, if the inheritor had a Quirk, [One for All] would adapt and alter itself to bring out not only its own full potential but also the full potential of the original Quirk as well. He couldn't help but wonder what kind of adaptions would take place to allow [One for All] to bring out the best of a Quirk like [Buster Hands]…

'No, none of that!' Toshinori reprimanded himself. 'He's proven himself to be strong and to possess potential, yes, but not worthy, not yet. I have to keep in mind that Sir Nighteye has recommended Young Tōgata as a possible contender, and I must admit that the young man's certainly grown splendidly under Mirai's guidance.'

Tōgata Mirio, who had chosen the name Lemillion for his Hero name, had truly become a powerful hero under the careful guidance of Toshinori's former sidekick. All of his problems with his Quirk, [Permeation], had been solved after just a year of interning under Nighteye and the youngster was already showing himself to be far more powerful than a fair amount of Pro Heroes that Toshinori knew.

Toshinori needed time to carefully select the one who would be his successor...either that or absolute proof that a person was perfectly suited to be the Ninth Bearer.

"...right. I'd better get this miscreant to the Police as I told Young Midoriya I would." the man nodded firmly before taking a deep breath as he swelled up in his muscle form. "Hahaha! Away I go!"

Leaping into the air, All Might neglected to notice that the large pocket on one leg of his cargo trousers had ripped thanks to the strain of both the bottles and the sudden shift in his size. The bottles fell to the ground and smashed, releasing the Sludge Villain into the wild once more.

"I'm free...!" the villain croaked once he'd managed to draw in enough liquid from the surrounding ground water to reconstitute himself and form a working face again. "That goddamned brat...! if he hadn't resisted, I wouldn't have been caught by All Might! He's gonna pay for this!"

Once he had rebuilt himself to a passable size, the Sludge Villain raced off in search of a body to hide in so he could scheme his revenge on both All Might and the damned boy who had caused the Number One Pro to catch him.

A Short Time Later

Musutafu Shopping Arcade

"You're shitting me!" Katsuki literally gawked at his childhood friend in disbelief. "A villain attacked you and you got saved by All Might?!"

"Yeah!" Izuku nodded excitedly, his eyes shining with enthusiasm. "He said that I did well to hold out against the villain for as long as I did! The Explosion Launcher was so useful against the villain that I bet you'd have done a better job though, Kacchan."

"Heh...damn right I would have." the blond-haired boy said smugly. His Quirk was awesome, after all. "But seriously, how the hell'd you manage to get ambushed by some shit villain while out shopping? I know you've got crappy luck Deku, but this is fucking pushing it."

Izuku pouted a bit at that. He didn't consider himself generally unlucky, but…okay maybe Katsuki had a point. "It's not like I asked for the slime guy to try and body-snatch me Kacchan." he grumbled

"Yeah, yeah...so do you finally get that your Quirk is almost as badass as mine?" Katsuki pressed.

"Y-Yeah...All Might encouraged me so...I'm gonna do my best to get into U.A. with you, Kacchan!" Izuku said determinedly.

This made Katsuki grin savagely. "Good, it wouldn't do for my future number two to graduate from anywhere else but the best. Now let's get something to snack on to celebrate you finally pulling your head outta your ass!"

"Kacchan!" Izuku pouted again, but followed his friend nonetheless.

It was a good thing that he did, because seconds later, a slimy arm smashed down where he'd been standing, sending Izuku stumbling forward. Whirling around and spotting the leering form of the Slime Villain, he leapt back and activated his Quirk again, the Air Buster appearing on his right arm. Even as he did so though, he shouted one word aloud.

"VILLAIN!"

Thankfully, everyone in the vicinity had the common sense to clear out as soon as the shout broke them from their stupor. The Slime Villain was easily recognizable since his earlier rampage had been broadcast across the local news and the net. The only exception was Katsuki, who had quickly moved to Izuku's side, small explosions already popping in his palms as he primed himself for battle.

"This the trash that attacked you? Fucking gross." the [Explosion] Quirk user growled.

"Don't let him grab you. He said he wanted to use my body as a disguise, which would apparently kill me." the greenette warned his friend.

Katsuki scowled, before a feral grin spread itself across his lips. "Like I'm gonna let Slimer over there get fuckin' near me."

"Well now, just the little brat I've been looking for." the Sludge Villain gurgled menacingly (a difficult feat) as he advanced on Izuku. "I owe you one, kid. Because of you, I got caught by that bastard! It was only sheer dumb luck that let me escape and now, I'm about to take my frustrations out on you!"

With a roar, the bulged slightly before dozens of sludge tentacles burst out of his form, arcing through the air to grab and lash at the two teens.

Both boys reacted immediately, leaping out of the way. Izuku had been 'persuaded' (read: forced at explosion point) to exercise with his childhood friend on a regular basis, so while he didn't show it as much as him aggressive friend, he actually had a fair amount of muscle hidden under his normally loose and baggy outfit.

"DIE!" Katsuki snarled, throwing an open-handed right hook into the nearest tentacle and letting off an explosion directly into the mass of ooze and slime, splattering it across the ground.

His eyebrow twitched noticeably as he noted the scattered slime started to gather and pull itself back toward the original slimeball.

"Tch, slimy bastard's a lot more resilient than he looks." Katsuki growled out in irritation. It was annoying having some no-name extra of a Villain being able to withstand (or at least mostly ignore) his Quirk. Goddamn regenerators were fucking annoying!

"His regeneration's not limitless." Izuku pointed out, sounding strangely calm as he used Air Buster to shoot down any tentacle that got near them. "The more you blast off, the longer it takes for him to pull it back together and the more it drains his stamina. A blast big enough to scatter his entire body into small pieces will knock him out in an instant, that's how All Might beat him."

"Hah! Dream on kiddies, neither of you've got anywhere near the power to match up with that smiling bastard!" Sludge Villain barked out a laugh, though he was keeping his distance away from both boys. He knew what the green-haired whelp had up his sleeves and he didn't want another taste of those explosives he could launch. The blonde was also dangerous, he didn't want to risk letting the little bastard's hands anywhere near him until he was sure of how strong those explosions could get.

"Then why not try me for size!" a loud voice called before a large, muscular arm slammed into the main body of the Sludge Villain, ripping through him…and doing nothing more than annoying and momentarily distracting the slimeball.

"Death Arms, the Punching Hero!" Izuku exclaimed before realizing that the large villain was totally unaffected by the Pro Hero's attack.

"Outta my way, weakling!" the Sludge Villain roared, using several long tendrils to grab Death Arms by the arm and hurl him bodily into the air.

"Sensei Hitsubaku Urushi Sarō! (Lacquered Chains Prison!)" another voice shouted. A flurry of tree branches lashed out of nowhere, one grabbing Death Arms around the waist, while the others constricted around the Sludge Villain, trying to bind him in place.

"Now, Backdraft!" the originator of the wood, the up-and-coming Pro Hero rookie, Kamui Woods, shouted.

"Backdraft Triple Hose Blasters!" a Hero wearing a costume reminiscent of a fireman's uniform shouted. He levelled his arms, both of which ended in hose nozzles, as well as a third hose, whose nozzle emerged from his shoulder, at the Sludge Villain and fired three tremendous blasts of water at his target.

"Like I'll let those hit me!" the living sludge shouted. He body bulged again before he seemed to explode, splitting into three streams of sludge (two carrying a single eye and the third holding his teeth) that snaked their way through Kamui Woods' tree branches and around Backdraft's water blasts, reforming to one side of the startled Rescue Hero Backdraft.

With a roar, the villain brought his entire mass to bear to swat the startled hydrokinetic, bringing his entire body around to smash into his side. The blow sent Backdraft flying into the air and away from the fight. With the biggest threat taken care of, the Sludge Villain returned his focus toward his original target. Deciding that he needed to get away before even more pros showed up, but not wanting to leave without getting his well-deserved payback, the monstrous villain surged forward again, aiming straight for the target of his vengeance, Izuku.

"Kacchan, we have to get out of here! It's after me!" Izuku shouted, knowing better than to waste time even trying to persuade Katsuki that he should leave him be. Bakugō Katsuki was not one to turn his back on a fight, particularly when his friend was involved.

"Where?" the blond asked, palms sparking from the urge to blast something with his Quirk.

"The rooftops! No bystanders up there!" Izuku replied confidently...just before Katsuki grabbed him, threw him over his shoulder and jumped, his hand letting out a dozen full-power explosions in rapid succession to provide both lift and propulsion.

"Explosive Turbo!" the blond boy roared as he sailed through the air. He and Izuku had been working on this trick for months now and he was pleased to finally put it to practical use.

Getting the timing down perfect and learning just how much force he needed to put in each blast to get the force he needed had been a bitch and a half.

"Get back here!" the Sludge Villain gurgle-roared as he started to climb up after the boys, even as the brand new heroine, Mount Lady, caught Backdraft.

"What's the plan, Deku?" Katsuki asked as the two boys landed on top of a three-story office building, Bakugō just managing to clear the mesh lining that surrounded roof, which like served as a smoking area for the building's employees, given the chairs and cigarette butts scattered around. The blond boy was no slouch when it came to fighting, but he had never been one for long-term planning, instead relying on instinct and improvisation. He could hold his own, of course, when it came to tactical and strategic planning, but those were Deku's things and Katsuki was willing to admit he was damn good at them.

Bakugō Katsuki might have been a singularly egotistical and arrogant individual in many ways, but he was willing to admit when someone else showed they could hold their own in a particular field.

It made crushing them with his own abilities all the sweeter, after all.

"Kacchan, I'm going to have to use that again." Izuku stated grimly as they raced to the other side of the roof, his eyes hardening as he glanced behind them where the first tendrils of the Sludge Villain had reached the roof's edge.

Katsuki blinked, before scowling furiously. "Are you fuckin' nuts!?" he barked out. "The last time you tried to use that damn trick you nearly blew the Light Buster to fucking kingdom come! Your arm was in a cast for two freaking months afterwards, Deku!"

"I know." Izuku bit out. "And this time I'll be using the Explosion Launcher."

Katsuki could only stare at his partner in shock. "Do you want to blow your entire damn arm off?" he growled out as they reached the edge of the roof.

The Sludge Villain had just finished pulling himself onto the rooftop and was oozing his body through the mesh siding.

"I know it's risky," Izuku agreed grimly, "but it's the only way we can pull out anything close to an All Might-level Smash."

Katsuki would have loved to argue that, but even he would admit that All Might was on a whole other level of power. He and Izuku had a couple ideas for super moves that might allow the [Explosion] user to match that kind of power eventually, but they were still months, if not years, of training away from being feasible

Gritting his teeth, Katsuki steppe forward. "Fine." He growled out. "But I swear if you lose a fucking arm, I'll rip the other one off myself and beat you bloody with it. I'll hold Slimer back until you're ready."

Izuku gave his friend a grin. That was Kacchan for 'don't get hurt' and 'I trust you.' "Thanks."

"Tch. You owe me an All Might figure for this." the [Explosion] Quirk user huffed. "The Silver Age one."

"Got it." the greenette nodded before shifting his right hand from Air Buster to Explosion Launcher in a flash of green light and aiming it right at the Sludge Villain. Then he began concentrating, even as Kacchan launched himself toward the rolling mass of slime and evil, explosion bursting from his hand both to splatter the villain and to launch himself out of the way of any incoming tendrils. All while screaming his native battle-cry.

"DIE!"

"Guh...you irritating little insect!" the Sludge Villain growled in annoyance as several explosions ripped through his body, splattering him across the rooftops and even sending several small blobs down to the ground below. He was forced to let those go, focusing on reassembling most of his body as he tried to swat away the exploding gnat.

As Katsuki fought, Izuku focused on his transformed right hand. 'The last time I tried this was when I was thirteen, and I haven't tried it since because of the damage it did.' he thought grimly. 'And that was just with the Light Buster. The Explosion Launcher is several times more powerful when it comes to sheer destructive potential...hoo boy, Mum is going to ground me for a month if she finds out about this.'

As a green glow started to build around his drum magazine, Izuku felt a small tendril of relief flow through his body. The last time he'd tried this, his Light Buster had simply started smoking and shaking the moment he'd started. Maybe his Buster's durability had improved as he aged, or perhaps the Explosion Launcher was simply more durable on its own.

'It might have something to do with it coming from Kacchan's Quirk rather than being purely mine. A part of Kacchan's Quirk Factor is his reinforced durability to better deal with the blowback of his explosions, perhaps [Buster Hands] copied that as well when it built Explosion Launcher.' He thought absently, before shaking his head, now was not the time to theorize on his Quirk.

He could do a more thorough analysis later if they survived this.

Refocusing, Izuku turned back to the task at hand; namely, concentrating the six rounds of explosive compound into one, single, overpowered blast. The 'Megaman' games that he'd researched from over two centuries ago had all had the ability to 'charge' their basic Buster, the so-called 'Mega Buster' that had really been the first 'upgrade' that the player got in the games.

Izuku had theorized that his own Quick could do the same by concentrating the converted 'ammo' of several regular Buster shots into a single Mega Buster shot. It had made sense in his head and all that he knew about Quirk Theory and how his own Quirk worked. Unfortunately, after his first failed attempt, and the resulting trip to the emergency room, his mother had personally banned him from trying again until he could get help from a Quirk Counsellor, something that wouldn't happen until he entered a Hero Program.

'Sorry Mum, but I have to try! It's the only chance we've got to even temporarily disperse the Sludge Villain's entire body!' Izuku thought determinedly. 'Even if can only combine just three rounds at once, that should be enough! So please...work!'

As if answering his unvoiced prayers, the drum of his Quirk brightened again before shifting, transforming from a six-round design into a three-round drum. Izuku smiled brightly at the change, before his smile turned into a savage thing that looked like it belonged on either his best friend or a particularly hungry tiger.

"Kacchan, now!" Izuku roared as he adjusted his sights on the Sludge Villain

Katsuki, whose movements were starting to get more erratic as he began to start feeling himself dehydrate and the Sludge Villain began to close in on him (not that he'd ever admit that anyone) snarled in response before bringing both palms down and releasing the most powerful explosion he could as he leapt into the air. The resulting explosion not only sent him flying backwards and away from the villain, but it left Slimer reeling as well from the shock and point-blank explosion that sent chunks of his scattering in all directions.

Katsuki landed in a roll a few feet to the side of his friend even as the one of the globs hit his friend right on the left hand where it bracing the Explosion Launcher. In a flare of muddy green light, the limb shifted into a barrel and tank set that looked like it was taken off a Super Soaker.

"Of all the times...never mind!" Izuku ground out as he quickly reverted his left hand and levelled his Explosion Launcher at the Sludge Villain again. "Three Round Concentration: Mega Explosion Buster!"

The sound of the shot being fired was less like a grenade going off and far more like the firing of a tank's main cannon. The sheer force of it threw Izuku back off his feet and into the roof's mesh siding. The projectile screamed forwards at breakneck speeds, such that by the time the Sludge Villain realized he was in danger, the Mega Explosion Buster had already struck his viscous body dead centre.

With a roar that would have put any of Bakugō's previous attempts to shame, the Sludge Villain detonated in a massive wave of concussive force and sound that almost completely covered the shriek of rage, fear and panic the villain let out. Small fragments of his viscous form flew out, covering the streets below even as his eyes and teeth were caught in the mesh screening that covered the sides of the rooftop.

And just like that, the danger was over.

"Ow..." Izuku managed to groan out as he slid down the side of the mesh barrier in a daze. There was a scorched hole in the roof where the villain had been standing moments ago. Several small scattered bit of his viscous body were scattered around the roof, all now looking more oversized, dried globs of snot than anything else. Down below Izuku could already hear the disgusted squawks of several civilians who'd likely been hit with charred slime.

He couldn't really blame them, that stuff looked gross.

Vaguely, he noted that one of the villain's eyes was caught in the mesh screen nearby.

"Holy shit...that was awesome!" Katsuki muttered out as he came over, looking at where the Sludge Villain had stood. "And you did that with a gun made from my Quirk...you think I could do something like that?"

"Well, yeah! It isn't like the Explosion Launcher is stronger than your Quirk; each 'round' is verifiably weaker than one of your regular blasts; I just focused three rounds into a single shot, so the resulting explosion was a lot more potent than what I can normally produce." Izuku said with a shake of his head to try and clear the ringing in his ears. "Think we should head home now?"

"Looks like the heroes want to scold us first." Katsuki snorted, looking over the side of the roof to see three clearly ticked off heroes standing on the ground and looking up at them pointedly.

"Better get it over and done with then." Izuku groaned. He was a bit uneasy about getting scolded by heroes, but what did they expect the two of them to do when they were being chased by a villain? Give up and let themselves be drowned in slime?

The scolding from Kamui Woods, Backdraft and Death Arms went on for about fifteen minutes before Katsuki's tenuous hold on his temper snapped and he cruelly pointed out how useless the three of them had been against the Sludge Villain, while he and Izuku had taken care of him for them.

That hadn't endeared him to the three heroes, especially Death Arms, but Kamui Woods, despite his irritation, clearly recognised that while Izuku and Katsuki had illegally fought a villain with their Quirks, they had also been within their rights to defend themselves under the self-defence section of the law. The Sludge Villain had clearly been targeting Izuku and that granted the boy the right to fight back and defend himself, with his friend being granted the same right by proximity. Because of that, he let the two off with a warning and shooed them away before the three heroes joined in on the efforts to gather up the scattered pieces of the Sludge Villain from around the area.

"Tch. Damned extras." Katsuki grumbled. None of the heroes on duty today had graduated from U.A. High, nor were they anywhere near the top of the Hero Rankings in any particular field or had they done anything to impress him personally. Thus, the [Explosion] user had quickly and effectively mentally regulated them to the roles of supporting characters, barely better than background characters due to the fact that they were Pros and thus deserved some acknowledgement.

They were simply beneath his notice or concern, and were thus treated as irrelevant.

"Kacchan, you shouldn't have been mean to them." Izuku said reprovingly. "They were just doing their jobs..."

"Yeah right! You and me did all the heavy lifting for them, Deku!" the blond boy scoffed. "We kicked Slimer's ass without any help from those extras, and now they're just being' pissy because a real main character and his side character showed them up." he stated arrogantly, before looking back at his friend curiously. "And didn't you even get a new gun out of it?"

"Eh? Yeah, I did." the greenette nodded automatically, hands clenching involuntarily. "Given that it was the Sludge Villain's Quirk that I got it from, I can think of a couple of things it could do..."

As Deku started to go into detail about a couple of the more likely possibilities his Quirk could've adapted the villain's Quirk into, Katsuki couldn't help but smirk wildly.

He and his sidekick were going to own U.A. High. And once they'd conquered there, the number one and number two slots were as good as theirs.

Behind the two boys, unbeknownst to them, Yagi Toshinori watched the two with curious eyes. He'd realised that he'd lost the bottles containing the Sludge Villain a short time after he leapt into the air from the building. Cursing his own incompetence, he'd run out of time for his transformed state and searched on foot for the villain. Toshinori had arrived just as the Sludge Villain had followed Izuku and Bakugō up onto the rooftops.

'The power of that blast...if I had to guess, I'd wager it was less than half as strong as a Texas Smash, but it was more concentrated in its area of effect. That's the reason it was able to disrupt that villain to the same extent.' the Number One Pro Hero thought seriously as he watched the two boys. 'The blonde young man with Midoriya wasn't completely wrong; while the heroes were in their right to scold them for recklessness, jealousy also played its part. It's hard for the old generation to accept that the next is going to surpass it so readily. Both boys possess a truly tremendous amount of raw power thanks to their own Quirks, and it's clear both had put in quite the effort to train them as well despite their young age. The amount of potential they both possess is simply enormous.'

Shaking his head, the skeletal version of the Hero All Might started to head home for the day, feeling every bit of the strain on his injured and mangled body. He should have kept the Sludge Villain more secure than stashing the bottles he had been trapped in than simply stuffing both into an overfull pocket! Had it not been for the fact that the Sludge Villain's targets had been capable of defeating him, Toshinori would be guilty of letting civilians be hurt due to his own failing.

'I had thought so before this, but Young Midoriya is indeed one to watch for.' Toshinori thought. 'I'll look him up later in the week. The determination he showed when he faced that villain down...it is very promising.'

Coughing up some blood as he moved, the old hero started to make plans.

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Next Chapter: Offer of an Upgrade

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Izuku's Gun Files!

Gun Name: Air Buster

Original Quirk: Initial Equip

Ammunition: Compressed Air

Magazine Size: 150 Shots.

Stats

Power: 2/5

Range: 4/5

Ease of Use: 5/5

Adaptability: 3/5

Gun Name: Explosion Launcher

Original Quirk: [Explosion]

Gun Based On: Milkor MGL Grenade Launcher

Ammunition: Concentrated Nitroglycerin Sweat

Magazine Size: 6 Shots

Stats

Power: 4/5

Range: 3/5

Ease of Use: 3/5

Adaptability: 2/5