Chapter Text
Katsuki may not have had Danger Sense like Izuku, but he’d been in this business long enough to get a sense: a sense of foreboding, like a too-cold breeze along the back of his neck, that told him shit was about to go down.
Today that sense was less whispering faintly in his ear and more buffeting him with the force of a tornado. He wasn’t a gambling man, but if he was, he’d bet his own ass that some serious shit was going to go spectacularly sideways at some point today.
He shifted his weight slightly. Up here on the roof of this shopping mall, he had a golden view of the train station and the busy intersection beside it. There was some national event wrapping up at the convention center today, and so the streets were even more jam-packed than usual as the travelers all made their way home after a long week of conventioning about whatever-the-fuck. The surge of new and overcrowded and overtaxed scents put Katsuki on edge like nothing else could on a day like this.
Not that the heroes weren’t prepared, in case things did go to shit. About five different Tokyo agencies were on call in this area today, including Best Jeanist’s, all working together to patrol every station, plaza, and hotspot until the crowds from this event finally went home.
No trouble on the streets so far this week, or today for that matter. But far from reassuring Katsuki, that only increased his anxiety. It was barely 2pm, after all. Plenty of time in the afternoon left for him to win his bet.
He heard the faint, familiar thrum of static rush up from behind him, and then Izuku was skidding to a stop beside him on the roof, leaving streaks of lightning behind him like brief afterimages after a camera flash. Katsuki side-eyed him, as the breeze wafted him in the familiar surface-scents unique to Izuku: like a forest at dusk, with the woodsy smell of pine needles crushed underfoot, laced with traces of cool mint tea. Soothing. Katsuki actually had to resist the faint urge to flare his nostrils and breathe more of it in. Most day-to-day surface-scents made Katsuki’s nose twitch, but Izuku’s smelled… well. Kinda fucking nice, actually. Not that that was much a surprise. Izuku’s personality was a literal Ray of Sunshine even in the darkest times – no, especially in the darkest times – so ‘course he would smell as good as one.
No, what was surprising, still to this day, was that Izuku was a Prime Alpha. Somewhere under his sunny personality, Izuku was hosting the metaphorical cage of a giant, monstrous direwolf.
Meanwhile, here was Katsuki. He’d been pegged as a Prime Alpha from day one by literally everyone. But when he’d finally presented way too late, fresh out of graduation from UA… well. Just days away from starting his new Sidekick contract at Best Jeanist’s agency, and his body had decided to present as the one secondary gender that society didn’t want to be a hero.
Fucking Prime Alpha-Omega bullshit.
“Hey, Kacchan,” Izuku greeted him. “Here to sub you out.”
Katsuki shook his thoughts away and glanced at the clock tower above the square. “Still got another three minutes.”
“You can go early, if you want?” Green eyes crinkled behind his mask. “I’m good to start my shift.”
Katsuki just shook his head again, one swift jerk of a motion. He shot another glance at the clocktower; beneath it, the timetables for the incoming trains had been delayed another three minutes.
Izuku followed his gaze. After a beat, he pulled out a couple of buns from one of his pockets. “Here for the long haul, then. Want one?”
“You’re gonna rot your teeth,” Katsuki warned him, “if that’s all you ever eat on patrol.”
Izuku only shrugged. “Suit yourself.”
“Tch.” Katsuki reached over and snatched the second bun from Izuku’s hand, ignoring the smile Izuku was fighting not to show in return. He popped open the bag, gaze returning to the streets below. “Danger Sense going off at all?” He asked, scanning a large group of people disappearing down the stairs to the underground subway. They were clearly tourists, judging by the sheer amount of selfies they were taking with ordinary-ass shit like the subway signs. And they were richly dressed tourists at that. Katsuki could almost smell the brand names and pricey perfumes and colognes from here.
There was a faint pop as Izuku opened his own bun. “Not really.”
“That’s not a no,” Katsuki pointed out. He took a bite of the bun, and the sweet taste of chocolate – his favorite flavor – poured over his tongue.
“Hmm.” Izuku chewed through a mouthful of his own bun – anko – and said, slowly, “I’m not getting any Danger Sense, just… just a regular sense, you know?”
Katsuki acknowledged this with a dip of his head. “Yeah. I know.”
They watched the streets in silence for a few minutes. The end of Katsuki’s patrol shift came and went, and still he lingered. He was supposed to return to his agency for a break, but that cold feeling was breathing down his neck harder than ever, so he texted his patrol group his status, tucked the bun wrapper away, and stayed right there on the roof.
He zeroed in on the intersection as a new color – yellow – saturated his vision: a long line of school buses were driving up to the streetlight, and just now stopping at the red light. Coming from a field trip at the national history museum down the street, most likely. All of the surrounding traffic slowed down and spaced out around them out of courtesy, giving the longer vehicles more room for their upcoming wide turns.
Katsuki’s lips quirked up into an almost-smile. After all the weird villain shit he’d seen throughout his years as a hero-in-training, it was always good to see shared moments of chivalry like this.
“Think they’re coming from the history museum?” Izuku idly wondered aloud. “Or maybe the aquarium farther down the – ”
His voice cut off abruptly, and both of their gazes snapped to the shouts rising from one of the paths to the subway. One man and one woman were running up the stairs, the man touting a huge bag over his shoulder. They shoved their way through a crowd of people in suits, knocking several of them to the ground.
In that same second, Katsuki and Izuku had already leaped from their roof and were streaking through the air in pursuit. With a single glance between them, they split up: Izuku went after the man and woman, and Katsuki went after the getaway car that had just pulled up on the side of the road.
The driver saw Katsuki’s explosions through the window, but before he could do more than shriek and move a foot toward the gas, Katsuki zoomed back and forth with quick bursts of his Quirk, and his AP shots popped one, two, all four of its tires, sending the vehicle lurching onto its rims.
Katsuki threw open the car door, searching for any weapons or other people inside. He caught only one fresh surface-scent, belonging to the driver: something like bananas and cream, but soured by the fear emanating from the man in thick waves. No one else, and there were no weapons in sight. That didn’t mean anything, though, when Katsuki had no idea what kind of Quirk this guy had. “Hands out,” he ordered, “slowly, or I pull them out myself.”
The driver stretched out his shaking arms, and Katsuki clasped a Quirk-blocker on his wrist.
Over on the sidewalk, Izuku had his two charges wrapped up securely in Blackwhip, Quirk-blockers strapped to their wrists, and the bag confiscated and restrained. Izuku was just peeking inside.
“Only fancy purses and wallets,” he reported.
Stolen from those rich tourists from earlier, no doubt. Figures. A little of the tension drained from Katsuki’s shoulders. “Call it in,” he ordered Izuku.
“Already am,” Izuku said, fiddling with one of his earbuds and murmuring something in a quiet voice.
In the meantime, Katsuki scanned the crowd and the streets. He could see a few heroes racing toward them from down the block for backup, but the crime was already fully contained. Other than the people in suits who’d been thrown to the floor, and the nosy passerby and even nosier traffic who’d all slowed or outright stopped to watch, there was no other action.
And yet… that sense of foreboding was as cold as ice now against the back of his neck.
That was when he smelled it: a new scent, so strong it drowned out all of the surface-scents of every other person on the sidewalk, drowned out even the soured-banana-cream smell of the driver in his charge. This new scent wasn’t a surface-scent but an under-scent, and it screamed Alpha at the top of its lungs.
Angry Alpha.
Angry, unmated Alpha.
One of the suited extras knocked onto the ground had lost control on his inner beast, and was snarling out at the crowd around him. He wasn’t wearing any scent-blockers on his neck, like a true asshole, and he clearly wasn’t on any suppressants, so his under-scent was pulsing unfiltered through the crowd.
Katsuki felt his inner Prime Omega react automatically to the scent, recoiling away. He tamped down the urge to hiss and spit, to let his Prime Omegan fangs extend and bare them in warning, to warn this potential mate away, to run. With the ease of literal years of training and practice, he shoved those instincts aside. He’d gone his whole career so far without outing himself as a Prime Omega, and he sure as fuck wasn’t about to do it now over this trivial shit.
Katsuki held out his palms, intent to blast his way over the car, get in the Alpha’s field of view, start working to calm him down –
But barely a sliver of a second later, there was a shudder and a horrendous crack – and a fissure spread from the Alpha’s feet and out, crawling across the asphalt and rupturing the street.
No, not just rupturing it – this Alpha’s Quirk was peeling the asphalt up and away like layers of an onion. Katsuki turned his wide gaze over the many, many cars and pedestrians now shrieking and panicking as the street literally crumbled beneath them. The subway ran deep under this street, and Katsuki could glimpse right through the fissure and down a long, long drop to the station far below. Holy fuck.
He and Izuku switched into crisis mode in an instant. Moving so fast he almost blurred, Izuku rushed forward to the Alpha, pinned him to the ground, and slapped another Quirk-blocker on the man’s wrist. Throwing out more threads of Blackwhip, he pushed back both sides of the crowd, keeping them from falling into the rugged crack growing in the sidewalk between them.
In that same second, Katsuki blasted halfway across the street. Even with the Alpha’s Quirk stopped, the edges of the crack were crumbling away under the weight of the cars now teetering over the edge. And the first school bus in line, which had just been turning through the intersection, now slammed on the brakes, but the driver couldn’t stop its momentum in time, and the nose of the bus went slipping over the edge of the fissure.
Katsuki could do a lot of things with his Quirk, but lift a goddamn bus or any of these cars was not one of them. “Oi!” He called out to Izuku without looking back, trusting that Izuku would know the rest of what he was asking. And without wasting a second to say or turn or do anything more than that, he propelled himself to the back of the bus and tore the back doors open.
The tilting bus was chock-full of screaming, panicking children, and a handful of teachers and the driver who were doing their best but were on the verge of screaming and panicking themselves. Katsuki popped his Quirk over his palms a few times, drawing their attention. “Everybody out,” he ordered, in as loud and as calm a voice as he could make it.
The teachers rallied around his order, herding the kids up the sloping floor to him, and Katsuki maneuvered them down to safer ground.
Through the front window of the bus, he caught a flash of green. Izuku was using strands of Blackwhip to hold not only this bus and the dangling cars in place but several other cars that had swerved around the bus and skidded to a halt and were now skidding over the fissure edge. But it meant Izuku was stuck there, while he kept the vehicles from dropping into the subway below.
Katsuki zeroed in on his own task, getting the children, then the teachers and the driver to safety as soon as possible. As soon as the bus was clear, he turned to the other cars hanging over the precipice. Screaming passengers were throwing everything from doors to windows to back trunks open, trying to escape their cars as Izuku held them at bay. Katsuki zoomed between them, pulling out extras and half-shoving, half-catapulting them toward safer ground.
In the background, he could hear the shouts of other heroes – the backup he’d glimpsed before had arrived and were helping the rest of the crowd, thank fuck. Katsuki pulled the last extra, an old man with wispy hair and half his teeth missing, from the passenger side of the final car. He carried the old man on his back to the driver, likely his daughter, already rescued and waiting a safe distance away.
“Thank you, Dynamight,” the old man’s daughter cried out, pulling the old man into a hug. “Thank you so much, oh my gods…”
Katsuki didn’t waste time replying, just checked at a quick glance that the old man wasn’t injured – a cut on his hand and a bruise on his elbow, but otherwise he was fine – and then turned back to Izuku. “Clear,” he called out.
Izuku was Floating above the center of the fissure, the fall to the subway station yawning far below him. Strands of Blackwhip were spread out from him like a spiderweb to hold all of the vehicles in place. His mask had slipped a little, and even from here Katsuki could see how hard he was sweating beneath his uniform. Blackwhip could lift more weight than Izuku could himself, sure, but that didn’t mean Izuku didn’t suffer the strain of it. With a heavy grunt, Izuku pushed outward with his hands, and his many, many strands of Blackwhip began sliding the dangling vehicles back up and out of the fissure, filling the air with the audible grind of metal and rubber against the asphalt.
Goddamn. For a single heartbeat, Katsuki was rendered utterly speechless by the sheer strength, and the sheer control over that strength, that Izuku had to be exerting to pull this off. Katsuki’s inner Prime Omegan instincts stirred at the sight, rising and pulsing beneath Katsuki’s skin. Prime Alpha, it whispered, Prime Alpha, and Katsuki felt his senses sharpen, felt his gaze zero in on the sweat pouring beneath Izuku’s mask. In the next heartbeat, he imagined getting closer, closer, pressing his nose under Izuku’s mask, breathing in himself how much better that sweat made him smell –
Fucking Prime Alpha-Omega bullshit, alright, and he did not have time for it. Katsuki forced the useless urges down and got his head back in the game. Twisting away, he searched the streets for the other backup heroes, expecting to see them calming down the rest of the crowd…
…and saw instead, utter chaos.
Because that annoying first Alpha, that asshole Alpha who had decided to travel through a crowded intersection today without any scent-blockers or suppressants, that dumbass Alpha with the overpowered Quirk who had started this whole mess, was still writhing and growling by the subway stairs. Even though his destructive Quirk was blocked, his Alpha wasn’t, and his angry scent and vicious snarls had triggered responses through the rest of the crowded street like ripples in a pond. Even if the rest of the extras around were wearing scent-blockers and were taking standard suppressants like good civilians, day-to-day C-grade suppressants couldn’t hold up against a face-full of angry unmated Alpha and the stress and adrenaline of a literal fissure opening in the goddamn street.
Triggered Alphas were snarling and flashing their claws and fangs at each other, triggered Omegas were hissing at Alphas who got too close or were fleeing or hiding under benches and under cars, and the unaffected Betas were trying in vain to bring their colleagues back to their senses or were running and screaming bloody murder. And it wasn’t just triggered people in the original crowd by the subway stairs, it was the crowds on every side of the intersection, the crowd that had spilled out of the nearby bank to see what was going on, the crowd just coming up from the other stairwell, the crowd Katsuki and Izuku had worked so hard to evacuate from their vehicles…
And to make it all worse, the cherry on top of the shitty fucking ice cream, more Quirks were coming loose, as triggered extras attacked or defended themselves. A street sign was melting like it was made of snow, giant pink bubbles were floating up in front of a dress store farther down the block, and an entire seafood storefront was splattered with what Katsuki really fucking hoped was just green paint.
Katsuki shared one single look with Izuku. He was running through a million strategies in his head, Blackwhip first to separate crowds, or explosions first to get everyone’s attention, or identify the backup heroes first since one of them might have a more useful Quirk for widespread crowd control…
But then he caught sight of Izuku’s expression. Izuku, still Floating above the fissure, had pulled his mask down fully. His face was drenched in sweat, and he was breathing hard enough that Katsuki could see his chest rising and falling from here. But his green eyes were like bright chips of steel. There was a furrow to his brow, a pained slant to his mouth, but his eyes, those were pure determination.
And then Izuku ripped off his S-grade scent patch.
At once, Izuku’s surface-scent thickened, roiled, bloomed with the release and mix-in of his under-scent, something heady, something overpowering, something Alpha: not just the woods at dusk but now the woods at dusk after a thunderstorm, laced with that near-electric smell, the feeling, the aftershocks of lightning strong enough to crack the sky. And beneath it all, that trace of mint still lingered, now thickened by the faintest, faintest swirls of something that marked him not just as Alpha, but Prime Alpha: something dark, and dangerous, like nightshade.
Katsuki had only smelled Izuku’s unique under-scent once before, when Izuku had presented during their third year in UA. But that had been before Katsuki had presented himself. And now, Katsuki knew this to be the single most powerful, most tantalizing scent he’d ever experienced in his entire life.
For one sliver of a heartbeat, that scent, rich and heavy and unmated, unmated, unmated, was all Katsuki could think of. He held out his hands, ready to blast his way to where Izuku was Floating, Prime Omegan fangs sliding down from his gums, a chirp building in his throat to call out to him, be the first to reach him, get his attention, because like hells he’d lose the rights to this scent to any other unmated Omegas in this courtyard –
In the next sliver of a heartbeat, he caught himself. He closed his palms, forced his fangs to retract, and shoved down his own emotions and his surface-scent into the barest, flattest pinprick.
In that same heartbeat, every other head in the intersection swiveled to face Izuku. The surface-scents of many, many, too many other heroes and extras in the courtyard reacted vividly. Several surface-scents mellowed and diminished – Alphas, no doubt – shrinking in the face of this new authority, and the surface-scents of several more others – unmated Omegas, no doubt – sharpened, swelled, sweetened, vying for attention.
Izuku ignored all of it, his own scent still and steady and unwavering and calm. He spoke down to the first Alpha who’d started all of this shit. “Be calm,” he said, and there was the barest, barest hint of a growl in his throat, the brief flash of his now-extended Prime Alpha fangs as he spoke. His voice was just loud enough to reach the Alpha, and yet his words still cut through the entire intersection like he’d shouted. “Sit down.”
That Alphan order and that Prime scent and that faint growl shivered down Katsuki’s spine and pressed, like a physical urge, a need, to bend his knees and lower himself to the floor. He fought that urge with every fiber of his being, even though it was like pushing back against a hand made of steel on his spine. He stayed on his feet through sheer will, as new sweat broke out on his forehead from the effort.
Around the intersection, other knees buckled, most fully, some slightly, as those likely Alphas and unmated Omegas were compelled to comply for different reasons. Izuku hadn’t even been talking directly to any of them, but they still stopped what they were doing, some of them sitting down right where they were on the concrete.
And the original asshole Alpha, bearing the full force of a direct order from a Prime Alpha, calmed completely, body shrinking in on itself, the angry acrid tones of his scent fading away, as he knelt on the ground before Izuku.
Izuku’s shoulders slumped, and his exhale of relief was so strong Katsuki heard it from where he was. “Good,” he said. “Thank you.”
The Alpha – now fully tranquil, gaze a little dazed – beamed, surface-scent brightening like a lamp in the face of this high praise.
“Stay calm, okay?” Izuku said – in his normal voice, now. He reached up to press the S-grade scent-blocker back onto his neck. Despite the calm in his scent, his fingers were shaking. “Please stay calm.”
Izuku’s under-scent faded as the S-grade patch settled in place, leaving behind just the woodsy dusk and mint, and the whole intersection settled. The triggered extras who’d been snarling at each other just moments ago came back to their senses and now shared sheepish looks.
The kneeling Alpha blinked like he’d just come from underwater, slitted pupils rounding back into the normal round human shape. He surveyed the intersection, the destruction, the busload of frightened schoolkids.
"Oh," he said, voice now impossibly small. "Oh, gods."