Chapter Text
AMAIN (adv): with full force
“Young Heroes,” All Might’s voice boomed over their radios, “The exercise begins… now!”
The front door to the building gave way to a sharp, well-placed kick; the plank of wood slid smoothly across the dusty floor to crash to splinters against the far wall. Izuku followed swiftly, hands held up in a rough imitation of a boxer’s guard.
The room was otherwise empty.
“Huh,” he said, raising a hand to scratch at the back of his neck. “I really thought he’d be waiting here for us. Jirou, can you-” He turned back towards his teammate, only to freeze.
Bakugo’s eyes shone with an unholy glee as he launched himself from his position perched on top of the door-frame.
A pulse of deep bass slammed into him from behind, knocking him just off-course enough that he missed Izuku. The dull metal cleats of his boots ground against the concrete floor as he landed in a skid.
He shot a glance at Jirou, then turned his attention back to Izuku. “Business as usual, huh, Deku? Found another girl to hide behind?”
“Oi,” Jirou cut in. “What are you, sexist?”
Bakugo blinked. “What?”
Jirou crossed her arms. “Why’s it matter that I’m a girl?”
Izuku frowned. “That is a good question. It’s not like I’m friends with Mei because she’s a girl. She just really doesn’t like you and is willing to say so.”
Jirou’s mouth twitched. “...you didn’t deny that you hid behind her.”
Izuku touched the tips of his fingers together. “I mean. That part was kinda true. Mei is… very good for hiding behind. Both physically and metaphorically.”
Jirou’s face gained that pinched expression again. “Was… was that a crack at her boobs?”
“Nah, its just that nobody else likes getting into the danger zone; 2.5 meter radius, doubled to 5 if she has a power tool.”
Bakugo rolled his eyes. “Well if Punk Wonder over there wants to run us through Feminism 101 right now, she’s free to go ahead,” he cut in acridly, before smirking. “May as well run down the clock so I win the exercise.”
Jirou clicked her tongue. “Not that it isn’t tempting, but I appreciate the reminder.”
And with a thump of rubber on dusty concrete, she made a beeline for the door to the next room.
Sparks crackled to life in the palms of Bakugo’s gloves as he reached them out behind himself.
Air hissed through Izuku’s pneumatic lines as his luminous visor descended over his eyescreens.
Bakugo shot after Jirou on a trail of smoke and flame. He was faster, but Izuku was closer, so...
> charting intercept course
In this form, Izuku Midoriya was a creature of inertia, momentum, and restraint. He could not simply move his legs as fast as he could; the torque that would create would flip him over before he could finish a step. His center of gravity and raw literal mass meant that there was little room for error within the laws of physics that governed bipedal motion.
When Izuku sprinted towards a point ahead of Bakugo, he did not shoot into full speed. He did not blink out of sight, only to reappear where he needed to be. He simply, sprinted.
And it was art in motion.
Pneumatics for speed, servos for precision, hydraulics for power; the triplex actuators sung a symphony of mathematics that carried Corpus Primus though space, feet cracking concrete to sink centimeters into the floor in the moments its full weight and strength rested against it.
As he approached his target speed, gears shifted and whirred, clicking into position within his legs. Microadjustments ran across his body as HERoS fine-tuned his performance in real time.
1.8 meters before the interception point, Izuku leapt.
Bakugo twisted away from his pursuit of Jirou and brought his arms up to block with his massive grenade gauntlets.
For a single moment, they both hung in the air. Powerless to alter the course of events, forced to wait for physics to see things through.
And then Bakugo– the ever-capable Katsuki Bakugo who had seared a path through Izuku’s childhood with an invincible determination– was drop-kicked with the full force of 612.32 kg of metal and electronics.
He exploded.
Jirou winced as a deafening bang rang through the hallway, followed by a small shockwave she felt even a room away. What the hell were those two doing in there…?
Not important, she reminded herself. It seemed like after that large explosion Bakugo was quieting down his Quirk use, so she took the opportunity to plunge her jacks into the wall and take a good long listen.
The first things she heard were Midoriya’s servos and motors and whatnot whirring and making their mechanical noises, paired with the ever-present low whine of whatever the hell was powering him. Nothing useful.
Deeper. A distant refrigerator unit, her own breathing, water running through pipes, old lights humming and flickering in that way that she’d had no choice but to grow accustomed to. Nothing useful.
Deeper. Air whispering through vents as the metal oh-so-quietly groaned and creaked at the temperature differentials. The omnipresent thrum of electricity, spread throughout the building but concentrated in particular rooms… Nothing useful.
Deeper. Down, beneath the low rasp of Bakugo’s breathing as rubble shifted around him and the smallest of zaps as electricity jumped micrometers in the loose-but-within-tolerance connection in Midoriya’s right shoulder and the crunch of tiny pebbles of concrete gravel under her shoes. Down beneath the creaking of wood and the settling of stone and the noise filtering in from the openings in the building and the way the gentle breeze still whistled across the edges of the ruined house for those with the ears to listen-
There. It was a few floors up, but she found the rustling of cloth, a ratcheting wrench, and the telltale ticking of the bomb.
Jirou turned her head to look directly into the lens of a camera and smirked.
And in that same spot, a sharp inhale.
Bingo.
Bakugo slowly climbed out of the soot-stained remains of the wall he’d been blasted into, lifting his ruined right gauntlet to his face to pull at the straps with his teeth.
Izuku stared in disbelief. “You cannot be serious right now. Is that- are those things sweat tanks? That’s- that’s so stupid! Why would you do that?”
“It was your fucking idea, asshole.” Bakugo defended, tossing the destroyed hunk of metal to the side.
“When I was six!” Izuku howled. “You- I- You can’t use a tank of nitroglycerin as a guard surface, Kacchan!”
“Yeah, I think I just figured that one out,” Bakugo spat, face going red for a different reason than usual. “Now are you gonna keep being a pussy, or are you finally going to grow a pair and-” he paused. “Oh, shit, I’m seeing it too now. Uhhh, why don’t you man up and- nope, still kinda misogynist.”
Izuku watched in bewilderment as Bakugo floundered.
After a few moments, the blond growled in frustration. “Ugh, this is a goddamn waste of time.” He clenched a fist and pointed it at Izuku, desperately trying to ignore his own blush. “FUCKIN’, FIGHT ME!”
Izuku looked down at the soot and scratches on his legs from dropkicking Bakugo, then looked back up into the furious red eyes. “Was that somehow not what we were doing?”
Bakugo simply roared wordlessly and charged at him.
Izuku’s eyes tracked his opponent’s form closely, paging through his Hero Notebooks in another tab to find the correct entry. Bakugo was, despite everything, the one person on this Earth that he would say he knew the best. His habits, his preferences, his unerring instincts… and his patterns.
And everything pointed towards this next attack being a right hook.
So Izuku lowered his stance, widening his legs for better leverage while preparing to catch the punch- only for Bakugo to juke out of the attack, slipping behind him to slam an armored knee straight into his back.
The blond boy clicked his tongue in derision, lightly stepping away as Izuku turned to face him again. “I’m not gonna do an attack if I can see that you’re ready for it, dumbass. Take this seriously.”
Izuku nodded, rolling his shoulder with a series of clicks before settling into a low boxer’s stance.
With a series of pops and crackles Bakugo spun into the space directly in front of him, swinging the single remaining gauntlet towards his head at a blistering speed. That… could be a problem, if Bakugo was willing to blow himself up just to get a meaningful hit in. Izuku swayed backwards, letting it pass in front of his face.
He stepped forward in an attempt to make up the distance, only for his face to meet Bakugo’s boot in a vicious spinkick.
He stepped back and raised his guard up, and with another bang Bakugo was in the air in front of him, hands raised into his own guard.
Izuku’s hand shot out in a right straight, only for his opponent to flex his hands and use another explosion to launch himself straight… down?
Izuku looked down just in time to catch Bakugo brace his arms on the floor and extend his entire body in a two-legged kick directly into his gut with an almost deafening clang.
They locked eyes for a moment as Izuku barely rocked backwards at the blow.
Bakugo flexed his hands once more, but Izuku closed his hand around his opponent’s ankles before he could escape.
He reached for the compartment at his waist that held the capture tape, but when Bakugo made for the pin on his intact gauntlet he abandoned the thought in favor of hurling the boy away as hard as he could. He saw what that thing did on accident, he was not at all interested in seeing whatever it did on purpose.
“Hah!” Bakugo barked, landing on all fours and skidding to a stop on the concrete floor. “That’s what I’m talking about! Where the hell were you hiding this for the past ten years?”
Izuku’s mouth quirked into an odd smile. “...being a robot is a fairly new thing for me, Kacchan.”
Bakugo looked at him flatly. “No shit. I’m not talking about that, dipshit, it’s the fucking- your fucking backbone, Izuku!”
Izuku stilled. Did he just… actually use his name?
“It took you ‘till UA to start fighting back!” Bakugo laughed- laughed! “Waste of my fuckin’ time, I’ll tell ya. Really thought you’d knuckle up sooner, but whatever. At least you finally did.”
Izuku stared at him. “...you spent ten years telling me I was useless, worthless, because I didn’t have a Quirk.”
Bakugo looked back at him with a disbelieving grin. “And you spent ten years not fighting me over it. What’s your point?”
“...you said I could never be a Hero without a Quirk.”
Bakugo rolled his eyes. “It’s like you’ve never heard of trash talk! Are we gonna go over every single insult? I tried a lot of them.”
Izuku looked straight into his eyes. “Why?”
And Bakugo… smiled bashfully. Scratched the back of his head. “Ah, well… if you were really gonna be a Quirkless Hero, you were gonna have to get used to fighting back, ya know? Like, a… take no shit, throw down with the haters kinda deal. The point’s kinda moot now that you got that whole robot thing going, but that was the idea.”
“And… why couldn’t you just say that?”
Bakugo blinked at the venom in the question, but shrugged. “That shit’s embarrassing! Besides, you knew we promised to be Heroes together. Why the hell would I go back on that?”
He had no idea how much it had hurt. He hadn’t meant it to. It all… hadn’t been on purpose.
It should have been a relief; Kacchan had always believed in him. This was what he’d always wanted! Izuku should have been able to shrug, laugh it off, and get his oldest friend back.
But for some reason, the thought evoked nothing but a terrible roiling in a stomach Izuku no longer had.
Because Katsuki Bakugo didn’t know what he’d done.
He hadn’t even thought to look.
And a constellation of starburst scars burned across Izuku’s skin, regardless of the fact that the body that had them was six feet in the ground.
Mei Hatsume calmly watched through the cameras as Jirou picked her way through the slapdash traps she’d strewn across the stairwell up. They were doing fairly well, for a pile of things she’d spent, what, thirty-four seconds throwing together? Probably mostly duds, but the Hero team didn’t exactly have the luxury of calling that bluff.
Engineering is hard, okay? Mei was a genius, not a wizard.
"Lady Hatsume…” her fork of HERoS murmured into her ears. “She knows where you are. It would be wise to move.”
“It would be,” the inventress agreed as she pried open a grey box set into the wall. “That’s the smart play. The safe route. But I ask you this, my faithful minion… If the Wright Brothers had decided to play it safe, would we have ever left the ground? If Benjamin Franklin had decided to do the smart thing and, I dunno, not flown a kite in a crazy thunderstorm, would we still have electricity? If Thomas Edison had- well, I guess if he’d stopped fucking with Tesla and come up with his own damn science- wait, no, that’d have been a good thing… ugh, you get what I’m getting at, right?”
"I suppose you mean to say we wouldn’t have aviation or electronics, in those hypotheticals?" HERoS-2 offered.
“Hell no!” Mei laughed, fingers tracing over the circuit breaker switches. “You think mankind would have stayed in the dark? Kept both feet on the ground? Nah, I’ll tell you what would be different.”
She splayed out her fingers and in a single motion shut off the power to the entire building. The room went pitch-black for a single long second, before emergency power kicked in and cast the room in a low, red glow.
“It’d be some other crazy bastard they went and put in all the books!”
A deafening clang rang out through the room as Corpus Primus blocked a vicious kick on its forearm, before stepping back out of range of the follow-up. A hand was held out, and a burst of flame bloomed into being. The android pushed through it heedlessly, using the smokecloud to close distance with its opponent and get inside his reach, but with a few well-placed backblasts its opponent managed to reclaim the space he needed.
Izuku watched through the cameras of Corpus Primus with a formless sense of distance lurking at the edges of a perception that didn’t quite translate into sight. He saw as his oldest friend rival opponent rained blow after blow on the unyielding metal of its chassis, read the status updates on his slowly deforming soot-stained plating, noted the internal temperatures rising as the heat of explosion after explosion worked its way through the cool titanium that made up its being.
And he felt nothing.
“Oi! Izuku, you lazy fuck! Stop just standing there and actually fight me!” Kacchan Katsuki Bakugo roared. “I know your bitch ass is on auto-dodge or some bullshit like that!”
The fight had gone on long enough that they’d adapted to one another; Bakugo had figured out exactly how much force he needed to put into his hits to at least threaten at dealing damage, and HERoS had enough combat data that dodging those hits was possible.
The timing was punishing; his opponent was simply fast in a way that Corpus Primus’ physics simply did not allow. He had mobility, jetting around the room on bursts of flame to attack from any angle he pleased, where Corpus Primus had to wait for him to enter its range.
[Uncertain; I hesitate to agree with your opponent, but actually fighting him seems to be the way forward. Unless, of course, you had some plan otherwise?]
Izuku mentally let out a long, low sigh before mentally commanding Corpus Primus to draw its capture tape from the hip compartment.
Each participant in the exercise had been given three; one per enemy team member, and a single extra. The tape itself was incredibly resilient, made from a material similar to Eraserhead’s Capture Scarf- although significantly less reactive. They wouldn’t be able to send out loops of the stuff to wrap Bakugo up at range; it’d have to be up-close and personal.
Corpus Primus lightly tested the tensile strength, pulling it taut between its hands.
Bakugo held position just out of range, watching it warily.
Corpus Primus moved towards him as quickly as it could.
Bakugo… ran straight into reach? Ducked past the outstretched tape that wasn’t ready for him to deliver a Quirkless open-palm strike to Corpus Primus’ chest? Slipped away as it finally recovered and tried to trap him with the tape?
Corpus Primus and Bakugo slowly circled each other, one holding forward the capture tape and the other bare hands. Izuku squinted in confusion at the video readout, trying to piece together what was going on. Was he… was Bakugo taunting him? Not even using his Quirk? Was this to show that he didn’t need- no, no, that way led to madness. Bakugo was fucking with him.
“You know, Izuku? There was a while a few years ago when I went to a bunch of martial arts dojos. Dropped ‘em all because they kept acting like I was some kind of villain brat or something- But I picked up a few things, so if you’re not gonna actually try you may as well play training dummy for me, yeah?” He held out a hand and gestured for Izuku to come at him.
Metal groaned as Corpus Primus complied.
Jirou stepped cautiously into the dark room, more out of a wariness for traps than any attempt towards stealth. Hiding was pointless when her opponent had doubtlessly watched every step of her approach over the cameras, and she knew it would be too much to hope that the power would have knocked out Nedzu’s surveillance.
"Step into my parlor, said the spider to the fly…" Mei Hatsume’s voice crackled to life on the intercoms, echoing from a dozen difference points at once. "I’m afraid you won’t find what you’re looking for in here, little Hero."
Jirou looked flatly into the darkness, where she could hear the Support Student’s breathing- not to mention the gleam of red emergency light that was caught on the metallic trim of the girl’s over-engineered goggles. “I know you’re in this room, Hatsume. And I can hear the bomb in here too.”
Hatsume pouted. “Drat,” she said, no longer over the intercom. “Well, there goes Plan A. Wanna play rock paper scissors over it?”
Jirou raised a single eyebrow.
“And there goes Plan B. I guess we actually have to do this, huh?”
Jirou didn’t dignify that with a response, and began to make her way into the room. If Hatsume had wanted to slow her down sight had not been the sense to target. It was child’s play to weave through the junk scattered across the floor, the simple acoustics of the room giving her enough to work with.
“Alright, my loyal minion. You know what to do.”
Jirou tensed; did she- no, Bakugo was downstairs and he’d sooner kill Hatsume than let her call him minion. Was there someone else, or-
"Now Playing: Caramelldansen.” The words that drove fear into her heart were delivered by a toneless voice from dozens of places throughout the building, followed immediately by the torment it promised.
The audio fidelity was shit. The acoustics were shit. The speakers were shit, and more importantly they were barely even synchronized, leaving the music to run into itself horribly as it echoed through the ruined halls of the building.
Just a hair’s breadth beneath the terrible music, Jirou heard the click of a power strip- and suddenly her world was a hell of light and sound. The lights of the room blinking on and off at irregular intervals and three floodlights shining across the room from different angles. Microwaves, fans, blenders full of gravel and god-knew-what-else running at full power to turn the mere fact of her existence into a sensory nightmare.
Her eyes watered, but she grit her teeth and rushed in towards Hatsume with her arms up in a guard.
The inventress grinned and reached out, snagging a hefty-looking monkey wrench and twirling it in her hand. Her other brought her goggles down over her eyes.
“Plan C it is!”
Corpus Primus’ teethpieces ground together under the luminous faceplate as it backed away from the 10th exchange with Bakugo with nothing to show for it.
He still hadn’t used his Quirk against it again, and he managed to evade each attempt to capture him almost easily. The shifting of weight required to move the robot body with any level of stability gave the blond all the warning he needed of its intentions. The closest Izuku had gotten was in the seconds between Caramelldansen starting to play and his opponent jumping up to obliterate the nearest speaker.
The song now echoed ominously from the adjacent rooms, but it was better than nothing.
Bakugo looked at him, unimpressed. “Izuku… you’ve gotten rusty, haven’t you? Were all those stalker notebooks all for show or something?”
Izuku looked back at him, irritated. “What are you talking about?”
“That, uh. Quirk Analysis thing you’ve always been super into. I thought it was, like, your thing.”
Izuku glared flatly. “Oh, so now your trash talk is gonna touch on the one thing I like about myself?”
“All’s fair in training and war, Izuku! But, uh. Yeah. I don’t sweat nitroglycerin.”
Izuku rolled his eyes. “Yeah, I know, its a nitroglycerin-like byproduct with a completely different chemical structure that gives it increased stability and efficacy-”
“I don’t sweat explosives,” Bakugo interrupted. “My sweat can explode. That’s my Quirk.”
Izuku’s head tilted. “I don’t get it.”
Bakugo let out a frustrated huff. “Ugh, I don’t have your custom-engineered nerd-words for it, so I’ll just show you the difference. It means that I can do this.”
And Bakugo raised an arm towards Izuku. And his hand opened into… a finger gun? Aimed straight at Izuku’s chest?
...Izuku’s chest. That Bakugo had spent the last few minutes hitting with open palm strikes, without triggering his Quirk, because a normal-sized blast wouldn’t get through his plating.
Izuku’s chest that had, like, twenty hands’ worth of sweat on it now.
Motherfucker.
Bakugo’s eyes shone gleefully as he triggered his Quirk with nothing more than a whispered, “Bang.”
And Izuku went flying backwards.