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It all started with a mid-tier villain named "The Inverse," whose quirk was less about destruction and more about sheer, annoying inconvenience.
They were cornered in a narrow alleyway in the Shizuoka Prefecture. Katsuki was already mid-air, palms popping with pre-ignition heat, while Shouto was sliding in on a ramp of ice to cut off the escape.
"Don't you two ever get tired of being so consistent?" the villain shrieked, throwing a glowing, translucent pulse of violet energy at the ground between them. "Let’s see how you handle a little emotional honesty!"
The blast didn't hurt. A sudden intake of breath felt like a momentary shiver that rattled their teeth, and then there was nothing. The villain was apprehended, mostly by Katsuki’s sheer temper, but the aftermath was immediate and confusing.
They stood by the police cruiser, the blue and red lights painting their hero costumes in artificial flashes as they attempted to provide their official statements to a very confused sergeant.
The air between them changed when Shouto turned his head. His dual-colored gaze catching the faint line of a scrape high on Katsuki’s temple where a piece of flying masonry had grazed him during the struggle. Without a second thought, Shouto’s hand drifted upward, his thumb grazing the raw skin with a touch so light it was almost a whisper, checking the depth of the wound with a focus that bordered on clinical. Katsuki frowns, not at the touch, but the minor sting underneath when Shouto's fingers brush against his skin.
"It’s a scratch, Katsuki. You’re okay," Shouto murmured, his voice retaining its usual steady cadence even as a familiar, stubborn pull of protectiveness tightened like a knot in his chest.
The Inverse quirk, however, was finished with subtlety and began to manifest their internal states with startling physical clarity.
On Shouto’s side, the controlled, flickering flame he usually held in check vanished, replaced by a radiant heat haze that began to roll off his shoulders in invisible waves. It wasn't the searing heat of a combat-ready fire, but rather the heavy, stifling physical manifestation of a warm heart that rapidly turned the immediate area into a tropical microclimate.
The nearby police officer, caught in the center of the sudden thermal bloom, began fumbling with his tactical vest and unbuttoning his shirt, wheezing out a desperate question about whether it had suddenly become 35°C in the middle of a Shizuoka autumn.
Katsuki’s reaction was equally transformative. As his face flushed with the heat of a standard defensive blush, his typical sweat-fueled explosions failed to ignite. Instead of the scent of nitroglycerin and the sound of popping sparks, a gentle, silent flurry of pristine white snow began to drift down from his spiky hair, coating his shoulders in a soft powder.
Katsuki tilted his head back in shock, his eyes widening as a single, perfectly formed snowflake landed directly on the bridge of his nose.
"What the hell is this?!" Katsuki barked, his voice rising in pitch, but the more he tried to summon his trademark rage and the more embarrassed he became that Shouto was witnessing him literally sparkle in the street, the more the Inverse quirk thrived.
The calm flurry suddenly caught a violent draft, and within seconds, the wind in the narrow alleyway picked up into a tiny, localized blizzard that swirled fiercely around the two of them, burying the police cruiser's hood in a layer of frost.
The transition from the open alleyway to the cramped interior of the hero transport vehicle was an error of meteorological proportions. As the heavy armored doors hissed shut, sealing them into a space no larger than a walk-in closet, the quirk found its perfect laboratory. The vehicle, designed to withstand ballistic impacts and high-grade explosives, was utterly defenseless against the anomaly developing in the backseat. The police officer driving was conflicted, unsure if he should be sweating or shivering.
The air inside the cabin didn't just warm up. It curdled into a thick, palpable humidity. Shouto sat with his hands folded in his lap, his expression as placid as a mountain lake, but the heat rolling off his left side was now pumping out the equivalent of a tropical rainforest. He was looking at the way Katsuki was pouting. The line of his jaw and the frustrated crinkle between his brows, and the more he admired the view, the more the thermometer on the dashboard began to climb toward staggering, scalding heat.
Opposite him, Katsuki was a localized weather disaster. Trapped in a mobile greenhouse with a literal human space heater, he felt exposed, seen, and dangerously understood. His standard "I’m not blushing. You’re blushing" defense was failing him entirely. Instead of the smell of nitroglycerin, the interior of the car began to smell like the first crisp morning of winter. His internal panic acted as a coolant, and a layer of crystalline frost began to crawl across the bulletproof windows, turning the transparent glass into opaque, flowered patterns of ice from the inside out.
"Stop it," Katsuki hissed, his voice sounding muffled by the thickening atmosphere as a literal icicle began to grow from the edge of the rearview mirror like a stalactite. "Stop...feeling things, Shouto! You're making it a goddamn sauna here! I feel like a fucking swamp."
Shouto didn't even flinch at the outburst. Instead, he tilted his head, watching a bead of condensation roll down Katsuki’s cheek. "I can't turn off how I feel about you, Katsuki," Shouto said with a devastating, reasonable calm that lacked any of his usual social filters, "Plus, you're creating flurries because of me."
The result was instantaneous and physical. Katsuki’s heart gave a violent, traitorous thump against his ribs, and the Inverse quirk responded to his spike of sheer, embarrassed affection with a structural failure of the cabin's climate. A massive, heavy thump of packed snow dislodged itself from the car's ceiling, falling directly into Katsuki’s lap and burying his support items in a freezing drift. He had literally snowed himself in because Shouto’s bluntness had caused a momentary lapse in his emotional defenses.
"I hate this shit!" Katsuki yelled, though he made no move to brush the snow off. "I hate every single part of this honesty quirk! Hey, cop! Speed the fuck up."
"Your pulse is elevated," Shouto noted, reaching out to brush a stray snowflake off Katsuki’s shoulder, which only caused the humidity to spike another five percent. "It’s very endearing, love."
* * *
The agency director hadn’t even bothered to finish their formal incident report. They didn’t need a quirk-diagnostic tool to tell them that the building’s HVAC system was currently fighting a losing battle against a pair of twenty-something emotional disasters. One look at the break room—which featured tropical condensation dripping from the ceiling tiles while intricate frost patterns aggressively reclaimed the surface of the 75-inch flat screen—was enough to seal their fate.
"It’s a workplace safety hazard, Dynamight," the director had said, their voice muffled by the thick fur hood of a heavy-duty parka they’d scavenged from the emergency winter-rescue locker. They were shivering visibly as the ambient temperature in the hallway swung wildly between sweltering and bone-chilling within the span of a few meters. "You’re creating a localized tundra every time you get embarrassed, and Shouto is effectively a high-output industrial heat lamp. Go home. Both of you. Nap. Decompress. Don't come back until the meteorological instability is resolved."
Katsuki erupted out of the building, his boots crunching through a layer of freakish, unseasonal slush that seemed to follow his footsteps across the agency’s polished marble lobby.
"I am not a damn safety hazard!" Katsuki roared, though his fury was undercut by the fact that a fresh, powdery dusting of snow was currently swirling around his head like a halo, reacting to his indignant pride. "I’m the fucking Number One Hero in training, and I don't decompress! I win! I don't have feelings that need to be evacuated!"
"You're glowing again, Katsuki," Shouto observed, stepping out into the sunlight behind him.
As Shouto walked, the air around him shimmered with a visible, lazy distortion of a golden heat haze that felt like a warm embrace. Every time his gaze lingered on the back of Katsuki’s neck, the humidity spiked, turning the crisp Shizuoka air into a heavy, floral-scented steam.
"Fuck off!" Katsuki snapped, spinning around with flushed, red cheeks. But as he looked at Shouto—who was standing there with a look of such calm, devastatingly honest affection—the quirk hit a new peak of atmospheric pressure. A sudden, violent gust of freezing wind whipped between them, momentarily blinding a nearby group of sidekicks with a flurry of white.
"I only 'snow' because you won't stop looking at me like I'm something worth looking at!" Katsuki yelled, the words bypassing his brain and leaping straight from his chest. "It’s annoying, and it makes my heart feel like it’s vibrating, Shou!"
Shouto blinked, his own heat haze intensifying until the pavement beneath his boots began to steam. "That was very brave of you to admit. I feel like my internal temperature rose another five degrees because of your honesty."
"Hurry the fuck up!" Katsuki trekked toward the parking lot, a miniature blizzard trailing behind him like a stubborn cape. "We’re going to the apartment!"
As he spoke, a particularly violent mini-blizzard swirled aggressively around his blonde spikes, caught in a localized draft created by his own rising blood pressure. A single, stray snowflake drifted down and landed right on the bridge of his nose, making him look less like a top-tier pro hero and more like a very angry, very expensive Christmas decoration.
"Katsuki, wait up," Shouto called out, trailing exactly three paces behind with a steady, unbothered stride.
On the surface, Shouto was the picture of clinical calm, but his internal thermostat was telling a much more compromising story. As he looked at the back of Katsuki’s neck again, he noticed the way his ears were tipped with a frustrated, flustered pink that he usually only saw in the privacy of their home. Shouto felt a wave of pure, concentrated fondness wash over him.
The result was a total collision. The air around Shouto began to shimmer with a heat haze, radiating a warmth so intense it was visible to the naked eye. The snow that Katsuki was producing didn't even have a chance to hit the ground near Shouto. It evaporated into a fine, ethereal mist the moment it entered his 30°C radius.
"You're steaming," Katsuki barked, spinning around to find himself staring into a wall of warm vapor. "You’re making a goddamn fog bank, Shou! I can't even see the street signs!"
"I can't help it," Shouto replied, his voice soft and devastatingly sincere. "The more I think about how much I love you, the hotter it gets. You’re literally making it winter because you’re embarrassed, and it’s very endearing."
"Shut up!" Katsuki yelled, the wind around him picking up until it was nearly a whiteout. "Stop having thoughts! Just...walk in silence and stop making it humid!"
Katsuki spun around in a sharp motion, his hair accessories whipping violently in a localized wind that had no business existing on such a clear autumn day. Especially since he was trying to get them back to the apartment they’d shared for over a year.
"Stop...stop doing that!" Katsuki roared, his voice bouncing off the brickwork of the narrow street.
"Doing what?" Shouto asked, blinking with a calm, wide-eyed innocence that only made the situation more volatile.
"The heat! You’re radiating like a damn space heater, and it’s making my skin crawl!" Katsuki shouted, thrusting an accusatory finger toward Shouto’s chest. As he did, the quirk manifested a physical betrayal. A single, perfect, and intricately crystalline snowflake drifted off the tip of his finger and settled gently on Shouto’s cheek.
Katsuki’s eyes widened in horror as he realized his own body was broadcasting his flustered state. He tried to jerk his hand back, but he saw Shouto standing there, who was looking devastatingly handsome and completely unaffected by the chaotic storm swirling around them. It made Katsuki’s heart perform a traitorous little flip in his chest.
The reaction was instantaneous and structural. A massive, literal snowdrift, having accumulated on a nearby shop awning from Katsuki’s previous outburst, suddenly lost its grip and dumped several pounds of freezing powder directly onto his head.
"You're snowing again, Katsuki," Shouto noted softly, his voice barely a murmur. He reached out and stepped firmly into Katsuki’s personal space, causing the quirk to shift into high-intensity overdrive.
As Shouto closed the distance, his left side began to glow with a soft, sunset orange that pulsed with the rhythm of his own rising affection. The temperature within their immediate five-foot circle spiked to a cozy, inviting temperature. It effectively turned the sidewalk into a private, summer-evening sanctuary that felt exactly like their living room on a quiet Friday night.
Katsuki felt the warmth hit him, and the more he leaned into Shouto’s presence, the more his cool defense mechanism triggered in a desperate attempt to maintain his composure. A soft, steady fall of large, fluffy flakes began to blanket both of them, swirling in the heat haze until they looked like they were trapped inside a living, breathing snow globe.
"I hate how much I don't want to move right now," Katsuki muttered, his forehead dropping against Shouto's shoulder as the blizzard around them finally began to settle into a quiet pulse of white.
"I know," Shouto replied, his hand finding the small of Katsuki’s back. "Your heart is beating very fast. It’s making the snow fall in a very pretty pattern."
"Shut up, you damn sap," Katsuki muttered, though his voice had lost its edge, sounding more like the low rumble of a distant, fading storm. He looked down at Shouto’s hand, which was now firmly interlaced with his own fingers, slotted together with a muscle memory that came from months of walking these same streets together.
Where their skin touched, the quirk was having a full-blown midlife crisis. A soft, constant hiss of steam rose from their joined palms as Shouto’s radiant "Emotional Heat" collided with the "Flustered Frost" radiating from Katsuki’s pulse point. It created a tiny, dense, and remarkably private fog that swirled around their hips, effectively shielding their joined hands and vulnerable expressions from the curious stares of the Shizuoka civilians passing by.
"You aren't actually mad," Shouto said, his voice an anchor in the swirling mist. He didn't look away, his thumb stroking the back of Katsuki’s hand in a deliberate movement that only sent the temperature of the fog up another few degrees. "If you were actually angry, it would be a hailstorm. I’ve seen your angry weather, Katsuki. This is...soft. This is a light dusting. You’re happy we have the day off."
"I'm happy you're a damn moron," Katsuki grumbled, though the inverse effect betrayed him instantly. As the words left his mouth, the wind died down entirely, and the snow falling around them transitioned from shards of ice to oversized, fluffy flakes that looked like feathers.
He tightened his grip, pulling Shouto closer so their shoulders brushed. He started walking toward their apartment again, his pace slower this time, no longer trying to outrun the feelings that were literally falling from the sky.
As they walked, they left an unmistakable trail behind them. A narrow, steaming path of melted wet pavement that was flanked on either side by exactly six inches of pristine, sparkling snow. It was a perfect meteorological map of their relationship. A core of intense, radiating heat protected by a high-walled perimeter of ice.
"We're going to have to mop the entire hallway," Katsuki added as they turned the corner toward their complex, his ears turning a fresh shade of pink. "You’re practically a walking sauna and I’m trailing a polar vortex. The neighbors are going to think the water heater exploded."
"I’ll help you mop," Shouto promised, his left side glowing with a content, sunset warmth. "But only if you keep holding my hand. The fog is keeping us centered."
"Whatever, Half-and-Half," Katsuki huffed, though he didn't let go. "Just don't start melting us in the elevator."
* * *
The apartment door hadn't even clicked shut before the entryway was transformed into a microclimate disaster.
Katsuki kicked off his heavy combat boots, his shoulders hunched in a defensive posture that was rapidly losing its battle against the Inverse quirk. Now that they were finally within the four walls of their private sanctuary, the internal floodgates of their world were swinging wide open.
Without the need to maintain the Dynamight persona for the public or the agency director, the overwhelming volume of his affection for his partner began to manifest physically. A thick, silent blanket of snow began to settle over the dark hardwood floor, coating the shoe rack and their discarded mail in a layer of glittering, heavy white that muffled the sound of their breathing.
"I’m making tea," Shouto said, his voice dropping into a private register he only used when the masks were off and the world was locked outside.
As he walked toward the kitchen, the air behind him warmed. The digital thermostat on the wall was spinning like a propeller, the numbers flickering in a desperate attempt to keep up with the localized heat wave. The snow on top of the shoe rack evaporated, and it was as if the frost wasn’t there to begin with. Every time Shouto’s eyes lingered on Katsuki’s messy blonde head, tracing the familiar tension in his neck and the way his hero gear sat heavy on his frame, the temperature in the hallway jumped another visible degree.
Katsuki followed him into the kitchen, his presence preceded by a literal cold front that caused the cabinet doors to creak and the overhead light fixture to frost over. He tried to lean against the counter with his usual practiced air of bored defiance. But, the moment Shouto turned and handed him a steaming mug of tea, the weather gave him away entirely.
As their fingers brushed, a contact that should have been routine after a year of shared mornings, a musical crack of frost raced across the glazed ceramic surface of the mug. The ice branched out in intricate fractals, perfectly mapping out the spike of adrenaline and affection blooming in Katsuki’s chest. Simultaneously, Shouto’s left side responded to the touch by emitting a soft, visible steam that curled around Katsuki’s waist like a warm, insistent ghost.
"You're doing it again," Katsuki grumbled, his voice sounding muffled and distant through the rising, humid vapor. "It’s like being trapped in a damn sauna with an industrial space heater. I can barely see the stove, let alone my own hands."
"And you’re currently snowing in the ginger jar," Shouto countered with a ghost of a smile, pointing his free hand toward the decorative shelf where a miniature, pristine drift had formed over the porcelain lid.
Shouto didn't pull back. Instead, he stepped even closer, intentionally crossing the threshold and entering the very eye of Katsuki’s localized storm. The temperature in the six-inch gap between their chests fluctuated wildly, a chaotic battle of thermodynamics that hissed and popped in the quiet of the kitchen.
"The villain thought this would be a devastating inconvenience," Shouto said, his voice dropping into a resonant tone that always made the frost on Katsuki’s shoulders melt into damp patches. "He thought making our internal filters physical, making our emotions visible to the entire prefecture, would...what? Embarrass us? Drive a wedge between us because we couldn't hide how we felt?"
Shouto set his own mug down on the counter with a quiet clack and reached out, his warm, glowing palm cupping the side of Katsuki’s face. The contact was electric; a fresh flurry of oversized, crystalline flakes erupted from the air above them, only to be instantly vaporized into a sweet, warm mist by the radiant heat of Shouto’s skin.
"He didn't realize," Shouto continued, his mismatched eyes locking onto Katsuki’s widening crimson ones, "that I've spent years wanting to show you exactly how much space you take up in my head. This isn't an inconvenience, love. It’s...honest. It's us."
Katsuki’s breath hitched, and for a second, the blizzard stopped. The air in the kitchen went perfectly still, the only sound being the heavy thud of two hearts trying to sync up. Then, the Inverse quirk hit its absolute peak.
A massive, heavy blanket of snow dislodged from the ceiling, burying the kitchen island in a foot of white, while the thermostat on the wall finally gave up and went blank as the room hit a sweltering, tropical temperature.
"I still hate you," Katsuki whispered, though he leaned his weight into Shouto’s hand, his eyes closing as the frost on his eyelashes turned to dew. "I hate that you're always right, and I hate that I’m literally burying the kitchen in snow because I want to kiss you."
"Then kiss me," Shouto replied, his left side pulsing with a brilliant, sunset-orange light. "And let the weather do what it wants."
Shouto reached out, placing both hands on the counter, effectively pinning Katsuki in. The heat rolling off Shouto’s left side was intense, now a radiating heat that felt like a sunbath on his skin. Katsuki didn’t wait for a second invitation. He reached out, his gloved fingers tangling in the front of Shouto’s hero suit to pull him in, and the moment their lips met, the temperature quirk triggered a total atmospheric collapse.
The kiss wasn't just physical contact. It was a head-on collision of two opposing weather fronts. Shouto’s heat surged, his left side glowing with a brilliant orange that turned the air in the kitchen into a thick, tropical haze. At the same time, the sheer, panicked intensity of Katsuki’s affection sent the barometric pressure in the room plummeting.
A bolt of static electricity danced between their joined lips, smelling of chilled metal and burnt sugar.
Outside their immediate circle, the apartment was a war zone. A gust of freezing wind swept through the kitchen, swirling the knee-deep snow into a vortex that rattled the cabinet doors. But in the center of the storm, it was perfectly, devastatingly, sweltering and perfectly, devastatingly cold. Katsuki leaned into the heat, his eyes fluttering shut as the frost on his eyelashes melted into teardrops of condensation.
Shouto’s hand moved from Katsuki’s cheek to the back of his neck, his fingers radiating a steady, pulsing 38°C that acted as an anchor against the blizzard. He kissed Katsuki with a slow, honest deliberation that stripped away the last of the blonde’s defenses.
The kiss finally broke with a lingering, humid friction, leaving both of them breathing in short hics. Katsuki stood there, dazed, his eyes unfocused and a rare, soft vulnerability clinging to the corners of his mouth. He looked like he was floating somewhere between a blackout and a breakthrough, his hands still anchored firmly in the fabric of Shouto’s hero suit as if letting go meant falling upward into the storm.
"Katsuki," Shouto whispered, his voice vibrating with a quiet, grounding gravity. "Look at the floor."
Katsuki blinked, his gaze dragging downward, his brain struggling to process the structural changes to their kitchen.
Around Shouto’s feet, the intense, radiating heat of his affection had carved a perfect, clear circle of melted water into the white landscape. But around Katsuki’s feet, the snow was nearly ankle-deep, and it was sparkling. It wasn't the harsh ice Shouto has used to pin villains to walls or propel himself through the sky. It was a soft, ornamental powder that caught the kitchen light in a thousand tiny, iridescent points from Katsuki’s overflowing affections for Shouto.
"You only snow like this when you’re happy," Shouto noted, his mismatched eyes wide with a soft sort of wonder that made Katsuki’s pulse spike. "I’ve spent years guessing based on the curve of your mouth or the way you cook my favorite meal. But right now? I can see exactly how much you love being home with me."
Katsuki’s face became a violent, unmistakable crimson. He tried to summon a proper, terrifying Dynamight snarl, but the quirk was a merciless judge. As he opened his mouth to deny it, a heavy, fluffy clump of snow dislodged itself from the stationary ceiling fan and fell directly onto his shoulder with a soft, mocking thwack.
"Shut up," Katsuki hissed, though the bite was gone, replaced by a raw, breathless honesty. He reached out and grabbed the front of Shouto’s shirt again, his knuckles white as he pulled him back into his personal space. "And you? You’re a walking forest fire. Every time I even look at you, you turn the fucking kitchen into a tropical resort. You’re obsessed with me, Shou. It’s pathetic."
"It is," Shouto agreed easily, his expression shifting into that rare, devastatingly open smile. He leaned down until their foreheads touched, the heat from his skin turning the snow on Katsuki’s shoulder into a gentle, rising mist. "It’s completely pathetic. I think I’ve been at a steady 38°C since we left the agency."
"You're a disaster," Katsuki breathed, his eyes closing as he leaned into the warmth, the blizzard around them finally settling into a pulse of white. He moves a hand away to brush his shoulder of snow but it does little to help.
"We're a disaster," Shouto corrected softly. "But at least the weather is consistent."
The effect was instantaneous. Where their foreheads met, the inverse forces collided with the kinetic energy of a weather front hitting a mountain range. The radiating heat from Shouto’s quiet, steady devotion and the chill from Katsuki’s flustered adoration cancelled each other out, neutralizing into a perfect, lukewarm mist that clung to their skin like a humid summer night.
They stood there in the center of their ruined kitchen. Half-submerged in a glittering white landscape, half-shrouded in a heavy veil of steam and breath. The only sound was the rhythmic hiss of the kettle and the soft, intermittent thump of snow sliding off the cabinets.
"The villain was a total fucking idiot," Katsuki muttered, finally letting his eyes slip shut. The snowfall around his shoulders slowed, transitioning from a frantic blizzard into a lazy, drifting flutter of oversized flakes. "He thought showing the entire world how we feel would make us weak. He thought if people saw the cracks in the number one spot, we’d be easy to break."
"He didn't realize that the cracks are where the light gets through," Shouto said, his voice dropping into that resonant, soul-deep tone that always made Katsuki’s pulse skip. His hand slid upward, his fingers tangling in the damp, blonde spikes at the nape of Katsuki’s neck. His palm radiated a heat that felt less like a quirk and more like a promise, a steady, unyielding temperature that anchored them both. "He gave me a map, Katsuki. I don't have to wonder anymore if I’m pushing too hard or if you need space. I have to look at the weather."
Katsuki let out a huff that was almost a laugh, a sharp exhale that sent a single, perfect snowflake dancing into the air before it landed and dissolved on his own eyelashes.
"Fine. You've got your map, you damn genius," Katsuki grumbled, his hands tightening on Shouto's suit as he leaned his full weight into the warmth. "But let’s get one thing straight. If you tell anyone that I sparkle or flutter or whatever the hell this is when I'm happy, I’ll melt your entire collection of limited-edition soba bowls. Every. Single. One. Got it?"
"Understood, Katsuki," Shouto replied, his left side pulsing with a sunset ombre light that made the frost on the windows turn into a golden dew. He leaned in, pressing his nose against Katsuki’s, the room temperature climbing a blissful, defiant three degrees. "Your secret is safe with me. Though, for the record? The sparkle is my favorite part."
"Quiet, you damn sap," Katsuki breathed, the snow around them finally settling into a soft, quiet dust. "Just...stay right there."
The kitchen was a disaster zone, a chaotic cross-section of a mountain peak and a tropical greenhouse. Every time Katsuki’s heart gave a traitorous, fond little thud against his ribs, another flurry of pristine white flakes drifted lazily from the ceiling, burying the linoleum and the base of the refrigerator in a silent, sparkling powder.
Katsuki stood by the kitchen island, clutching his coffee mug like a tactical weapon, his knuckles white against the ceramic. He looked down, his scowl deepening as he shifted his weight, trying to maintain some semblance of his heroic dignity while standing in a literal snowbank. A soft, wet squelch echoed through the quiet room as the moisture finally won the battle against his wool fibers.
"Shou," Katsuki growled, his voice dropping into a low, dangerous purr that usually signaled a very specific kind of domestic frustration. "The fucking snow is making my socks soggy. Do something about it before I blow the floorboards into the next ward."
Shouto, who was currently radiating a gentle, consistent warmth that smelled faintly of toasted cinnamon and the expensive tea Katsuki bought him for his birthday, looked over from the stove. He didn't point out that the snow was entirely Katsuki’s own fault. A physical, undeniable receipt of how much he liked being home and out of the public eye. He didn't mention that the quirk was merely acting as a translator for the affection Katsuki usually kept locked behind a scowl. He sighed, a sound full of devastatingly patient affection that made the humidity in the room spike another three percent.
"I've got it, Katsuki. Stay still."
Shouto walked over, the air shimmering with a visible heat haze around his left side that turned the falling snow into a fine, ethereal mist before it could touch his hair. He sank to one knee on the kitchen floor, right in the middle of a four-inch drift, the cold powder melting instantly into a clear, steaming pool around his leg.
A thick, white mist hissed upward as the ice turned straight into steam, the kitchen vanishing for a moment in a dense, opaque cloud of their own making. Within seconds, the floor was bone-dry, the moisture effectively vaporized by the sheer intensity of the radiant heat Shouto was pumping out. Even the dampness in Katsuki’s socks had been baked out by the localized radiator effect, the wool fibers fluffing back up as they were hit with a blast of dry, heated air like a blow dryer.
Katsuki let out a long, shaky exhale, his toes curling instinctively against the now-toasty tiles. The sudden transition from freezing slush to a heated floorboard sensation was enough to make his knees go a little weak, though he’d sooner die than admit it.
"Better," he muttered, clutching his coffee mug with both hands and looking anywhere but at the man kneeling at his feet. His gaze fixated intensely on a magnetic timer on the fridge, his pulse finally slowing from a frantic gallop to a steady, heavy thrum.
Shouto didn't get up immediately. He stayed there for a second, his weight shifted back on his heels, his thumbs tracing the line of Katsuki’s Achilles tendon through the fabric of his socks. The touch was steady and grounding, his palms emitting a heat that felt less like a quirk effect and more like a heartbeat.
"Are your feet warm now?" Shouto asked, his voice deep and vibrating through the floorboards. He looked up, his mismatched eyes catching the light of the overhead lamp, looking far too content for someone currently kneeling in a puddle of evaporated snow.
"Yeah. They're fine. Get up, you're being weird," Katsuki snapped, though there was no heat in the words. Only a desperate attempt to regain some semblance of his usual prickly exterior. He nudged Shouto’s shoulder with his shin, a gesture that was supposed to be a dismissal but ended up feeling more like an invitation.
Shouto finally rose, the air shimmering around his left side as he stood. "I'm not being weird," he said simply, closing the distance until their chests were inches apart. "I'm being thorough. I don't want you catching a cold because I made you flustered."
Shouto stood up with a deliberate, fluid grace, a small, triumphant smile tugging at the corners of his lips as he surveyed the literal winter wasteland they had made of their kitchen. He didn’t pull away immediately. Instead, he leaned into Katsuki’s personal space, pressing a brief, lingering kiss to the very corner of Katsuki’s forehead. A spot he knew was particularly sensitive to the heat.
"I'm glad," Shouto whispered, his breath a warm, humid puff against Katsuki’s skin.
The kiss was the absolute final straw for Katsuki’s internal barometer. His face went from its usual pale, combat-ready composure to a vibrant red in a literal heartbeat. His heart hammered against his ribs with the force of a percussion grenade, and the quirk responded to that surge of raw affection with the localized fury of a high-altitude mountain blizzard.
PLOP.
A massive, heavy mound of fresh, perfectly white snow dislodged itself directly from the crown molding of the ceiling. It fell with a wet, heavy thud, burying Katsuki’s feet back up to the shins in an instant.
Squelch.
The sound was unmistakable. The definitive, miserable squelch of expensive socks surrendering to an icy fate for the second time in ten minutes. Katsuki looked down at his ruined footwear, the steam rising from the snow where it touched his heat-radiating ankles. He looked back at Shouto, who was already radiating a fresh, shimmering wave of amused heat that smelled like a sun-drenched afternoon.
"Shou," Katsuki warned, his voice cracking slightly as a fresh flurry of snowflakes tangled in his eyelashes. "I'm going to kill you. I'm going to blast you into the middle of the Pacific. Fix it again."
Shouto didn't even flinch at the threat. He reached for the kettle, his shoulders shaking with a rare, silent laughter that caused the kitchen's ambient temperature to climb. The steam from the sink and the snow from the ceiling were beginning to create a thick, domestic fog that blurred the edges of the room.
"It's going to be a long day, Katsuki," Shouto noted, his voice full of a devastatingly calm affection as he started making the tea. "But I think I have enough internal battery to keep your feet dry for at least another six hours. Provided you don't keep getting flustered."
"I am NOT flustered!" Katsuki roared, which immediately triggered a second, smaller snowdrift to fall directly onto his head, dusting his blonde spikes in white.
"The weather report says otherwise," Shouto hummed, pouring the water. "But don't worry. I’ve always liked the snow."
* * *
The bedroom door stood open like a portal to a failed science experiment, the cool air from the hallway hitting a wall of humid, pressurized heat that made the doorframe literally groan.
Inside, their king-sized mattress was currently the epicenter of a localized weather front. Because the bedroom was their ultimate safe space, the quirk had an absolute field day with their shared history. A thick, sparkling layer of frost had climbed up the expensive oak headboard like a fleet of frozen ivy. The duvet looked less like bedding and more like a pristine, snow-covered hill in the Swiss Alps.
Meanwhile, the air in the room was so thick with Shouto’s subconscious, sleepy affection that the wallpaper was starting to peel at the corners from the sheer humidity. The ceiling fan was struggling to rotate through the dense, tropical mist, its blades slick with condensation that smelled faintly of Katsuki’s peppermint shampoo and Shouto’s cedarwood soap.
Katsuki stood in the doorway, arms crossed tightly over his chest to keep the inner shivers from manifesting another flurry. A single drip of melting frost hitting the hardwood floor punctuated the heavy silence.
"No," Katsuki said, his voice flat, final, and dangerously close to a growl.
Shouto leaned against the doorframe next to him, tilting his head with a look of genuine, misplaced architectural appreciation. "It looks...cozy. In a remote winter cabin sort of way." ""We could burrow under the frost."
"It looks like a swamp, Half and Half." Katsuki pointed an accusatory finger at the expensive Italian linens currently being colonized by a miniature glacier. "Shou, we paid a fucking arm and a leg for this bed. I’m not going to fuck it up with permanent water damage or localized heat warping. If you start radiating in your sleep because you're having a good dream and I start blizzarding back at you, we’re going to wake up in a literal indoor lake."
Shouto sighed, the air around his left shoulder shimmering with a visible heat that felt like a warm hearth. "You're right. The manufacturer's warranty on memory foam probably isn't rated for inverse quirk saturation or extreme thermal cycling."
"Damn right it isn't." Katsuki turned on his heel, his soggy socks making a pathetic, rhythmic squish sound on the hardwood that completely undermined his authoritative tone. "Change of plans. Let’s sleep in the living room. The leather couch is waterproof, and we can hunker down on the rug."
"The rug is wool, Katsuki," Shouto noted, trailing after him as a fresh flurry of snowflakes drifted from the hallway ceiling. "It’s going to be a very damp morning."
"I don't care," Katsuki barked over his shoulder, his ears turning a bright, tell-tale crimson. "As long as you keep your internal heater at a steady heat, I might actually get some sleep without snoring on my own face."
They constructed a tactical fortress next. Katsuki dragged out the heavy-duty, reinforced sleeping bags they usually reserved for high-altitude rescue missions. The ones specifically engineered with quirk-resistant fibers to withstand extreme temperature fluctuations without melting or shredding.
"Get in," Katsuki ordered, shoving a sub-zero-rated, industrial-grade bag toward Shouto with enough force to suggest he was bracing for a siege.
"Together?" Shouto asked, his voice tilting upward as a sudden spark of amusement hit his chest.
The living room temperature jumped from standard to sweltering in three seconds flat. The condensation on the floor-to-ceiling windows began to run in thick, rhythmic rivulets, effectively blurring out the city lights of Shizuoka.
"Yes, together, you damn walking heart!" Katsuki snapped, though his ears were turning that deep, tell-tale shade of pink that usually preceded a blizzard. "If I’m on the other side of the room, I’m going to wake up buried in a drift. If you’re right here, you can at least melt the evidence before it hits the rug."
As they zipped themselves into a tangled, complicated mess of limbs and high-tech fabric on the oversized Persian rug, the inverse equilibrium finally started to find its center. Katsuki tucked his head firmly into the crook of Shouto’s neck, his damp blonde spikes tickling Shouto’s jaw, while Shouto wrapped his arms around Katsuki’s waist, pinning him close enough to feel the throb of his heart against his own ribs.
For a few minutes, it was quiet. The only sound in the living room was the distant hum of the city and the soft, intermittent crinkle of the high-tech sleeping bag settling over the rug.
"Katsuki?"
"What?" The response was immediate but lacked its usual explosive edge, sounding more like the low rumble of a fading storm.
"It’s snowing on my arm."
Katsuki let out a long, muffled groan against Shouto’s collarbone, his forehead pressing deeper into the junction of Shouto's neck. A light, powdery dusting of snow was indeed falling inside the pressurized seal of the sleeping bag, coating Shouto’s left forearm in fine, glittering white crystals that looked like fallen stars against his skin.
"I can't help it," Katsuki muttered, his voice uncharacteristically soft, muffled by the layers of nylon and Shouto's shirt. "You're too warm. It’s...annoying. It's making my head fuzzy."
Shouto didn't point out that "annoying" clearly meant "comfortable." He didn't mention that the quirk was currently translating Katsuki's peace into a winter wonderland because he felt safe enough to let his guard down. He adjusted his grip, shifting his weight so his left side emitted a steady hum of heat that acted like a localized dryer for the damp wool of Katsuki’s socks.
"It’s okay," Shouto whispered, his own eyes finally sliding closed as the tension of the day evaporated into the humid air. "I like the snow, Katsuki. It reminds me that you're here. That you're not out on a solo patrol or stuck at the agency."
Katsuki didn't complain this time. He didn't snap back with a retort about how here was the only place he ever wanted to be. He let out a final, shaky huff of breath and squeezed Shouto’s hand under the heavy layers of rescue-grade fabric.
As the apartment settled into a deep, domestic silence, Katsuki finally fell asleep to the rhythmic, soothing sound of steam hissing softly where their devotion met in the middle. Outside the sleeping bag, the living room continued to transform into a silent, sparkling tundra, but inside their fortress, it was exactly the right temperature.
* * *
The walk to the agency the next morning was suspiciously, almost unsettlingly, normal.
There was no crunch of supernatural snow under Katsuki’s combat boots, and no shimmering heat haze distorting the morning air around Shouto’s left shoulder. The Musutafu sky was a boring, cloudless blue, and for the first time in twenty-four hours, the pavement stayed dry and gray beneath their feet. Without the constant, swirling visual of their own hearts on display, the world felt strangely quiet, empty of the sparkling white fractals and golden humidity that had defined their apartment only hours ago.
They stood in Recovery Girl’s office, the clinical, familiar scent of antiseptic and strawberry gummies filling the small space. She hopped down from her stool, the wheels of her medical chair clicking against the tile as she tucked her stethoscope away with a professional nod.
"The inverse effect has fully dissipated," she announced, peering at them over the rims of her glasses with a knowing, weary look that suggested she’d seen far stranger domestic disasters in her tenure. "Your biological thermostats have finally reset themselves to their factory settings. No more indoor blizzards, Dynamight. The building’s HVAC system can finally take a breath. And Shouto, you’re back to your usual half-and-half self. Your internal regulation is stable. You’re both cleared for duty."
Katsuki let out an exhale that didn't produce a single snowflake. He shifted his weight, and for the first time since yesterday, his socks didn't make a miserable, squelching sound inside his boots.
"About damn time," he grumbled, though his hand instinctively twitched toward the spot where he’d spent the night gripping Shouto’s shirt. "That villain was a waste of my fucking time. Making me snow like a goddamn snow globe."
They walked out of the infirmary and into the quiet, clinical hallway of the agency. Usually, this was the part where the post-mission adrenaline would kick in, where Katsuki would bark about hitting the gym to sweat out the weakness or Shouto would offer to get lunch at the nearby soba shop.
But as they stood by the elevators, the silence felt heavy, layered with a strange, phantom weight. For the last twenty-four hours, the air between them had been thick with physical evidence. Every spark of affection, every surge of protective heat, and every flustered chill had been laid bare in glittering frost and rolling steam. Now, the atmosphere was just air. Oxygen and nitrogen, unburdened by the weather of their hearts.
Katsuki looked down at his hands, his brow furrowed in a way that wasn't quite an angry scowl. He flexed his fingers, his subconscious clearly expecting a stray, ornamental snowflake to drift from his palm, but there was only the faint, familiar scent of nitroglycerin and the calloused reality of his skin. He let out a huff that didn't produce a single puff of vapor, shoving his hands deep into his hero suit's pockets.
"Great," Katsuki muttered, his voice echoing a little too loudly in the sterile hall. "Back to normal. No more damn soggy socks. No more digging the kitchen out of a snowbank. Finally."
He kicked at the floor, but there was no satisfying squelch, only the dull thud of leather against linoleum.
Shouto didn't say anything immediately. He was staring at the brushed metal of the elevator doors, his expression unreadable and his left side perfectly, stoically cool. The vibrant sunset-orange glow that had pulsed with his every heartbeat yesterday was gone, tucked back behind the high walls of his professional composure. He reached out, his hand hovering tentatively near Katsuki’s arm from the warmth he’d been anchored to all night before he pulled it back, his fingers curling into a loose fist.
"Yeah," Shouto said, his voice unusually flat, lacking the resonant hum that had vibrated through the sleeping bag. "Normal. The agency is exactly 22°C. It’s efficient."
They stepped into the elevator, the doors sliding shut with a clinical hiss that seemed to emphasize the sudden vacuum between them. Under the influence of the quirk, if Shouto had felt this wave of sudden loneliness, the small space would have hit 30°C in seconds, the air turning thick and humid with his unspoken need.
Now, the digital climate display above the door stayed stubbornly and mockingly fixed at 21°C.
Katsuki shifted his weight, the silence of the descent feeling louder than any explosion he’d ever set off. He looked at Shouto out of the corner of his eye, tracing the line of his jaw and the stillness of his shoulders. It was a secondary inverse effect he hadn't prepared for: he missed the physical receipt. He missed the atmospheric pressure. He missed knowing, with absolute scientific certainty and a flurry of snow, exactly when Shouto was thinking about him.
"You're too quiet," Katsuki snapped. The words were deep, but they lacked his usual explosive heat. They sounded more like a question than a demand.
"I was thinking," Shouto replied as he leaned his back against the chrome railing. He didn't look up, his mismatched eyes fixed on the floor. "It’s harder this way. I realized I’ve grown lazy over the last twenty-four hours. I have to actually tell you that I’m happy to be here with you. I can't let the thermostat do the talking."
Katsuki’s ears turned a vibrant, unmistakable pink in the old-fashioned way, driven by blood and pulse rather than barometric pressure. No snow fell from the recessed lighting. No intricate frost crept across the brushed metal of the elevator doors to map out his racing heart. There was only the hum of the motor and the two of them, stripped of their feathers.
"You don't have to say it, you damn sap," Katsuki grumbled, though his scowl was failing him. He stepped pointedly into Shouto’s space, closing the gap until his shoulder bumped firmly against Shouto’s left side.
It was cool. Solid. Consistent.
"I’m not an idiot," Katsuki muttered, his voice dropping so only Shouto could hear it over the whir of the elevator cables. "I know when you're radiating even if the walls aren't melting. Just...don't stop doing it. The quiet is annoying."
Shouto finally looked up, a small, genuine spark of light returning to his expression. He shifted his weight, leaning back into the contact until the pressure of Katsuki’s shoulder was a steady, grounding anchor.
"I won't stop," Shouto promised. "But I might still buy that waterproof rug as a reminder."
Katsuki let out a huff that was almost a laugh. "Fine. But I’m picking the color."
Katsuki reached into his hero suit pocket, pulled out Shouto’s hand with a gruff, practiced efficiency, and interlaced their fingers. He squeezed hard, not with the tactical grip of a rescue maneuver, but with the kind of grounding pressure that said, "I'm not going anywhere, and neither are you."
"I liked the snow," Shouto admitted softly. His thumb traced the calloused line of Katsuki’s palm, a slow, rhythmic movement that would have sent the elevator into a tropical humidity spike only an hour ago. Now, it was skin on skin, quiet and intentional. "It was nice seeing how much you like cooking for me. I didn't realize that miso soup was worth a two-inch drip."
"I hated the snow," Katsuki lied, the words coming out as a reflexive habit, but his actions immediately betrayed the defense. He pulled Shouto’s hand up, pressing his face briefly into the warmth of Shouto’s knuckles. The scent of cedar and high-grade tea lingered there, a far better atmospheric indicator than any quirk. "But...I guess the sauna thing wasn't the worst. At least I knew you weren't bored with the movie."
Shouto smiled at a rare, lopsided curve of his lips that used to make the digital thermometers in the agency literally explode. "I'm never bored with you, Katsuki. Even when the room isn't in summer heat, that hasn't changed."
Katsuki let out a genuine laugh that echoed in the small space of the elevator. The doors chimed, sliding open to the busy main floor of the agency, but neither of them moved for a second.
"Good," Katsuki said, his crimson eyes locking onto Shouto’s with a fierce, unshielded honesty. "Because if you start acting damn chilly now that the quirk is gone, I'm gonna blast you into next week. No weather report needed to tell me when you're being a bastard."
They stepped out of the elevator together, their shoulders brushing in a coordinated stride. To the rest of the world, they looked like the formidable, composed pro-hero duo the public relied on—steady, professional, and untouchable.
But as they walked through the lobby toward the equipment lockers, Shouto leaned in, his voice a private murmur that bypassed the cameras and the crowds. "I'll try to keep the temperature up, Katsuki. But you might want to check your locker when we get back tonight."
"Why?" Katsuki narrowed his eyes.
"I found a single, sparkling snowflake on my hero cape this morning," Shouto said, his eyes dancing with a quiet, triumphant light. "I think the Inverse quirk left us a souvenir. I put it in a jar in the freezer."
Katsuki’s face went that familiar, vibrant crimson again. He didn't produce a blizzard, and the ceiling tiles stayed perfectly dry, but the way he squeezed Shouto’s hand told the entire story.
"You're a damn sap, Shou," Katsuki grumbled, though he didn't let go. "But fine. We’ll keep it. Just don't let it melt."