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The training session at Ground Beta had been a grueling exercise, but for Shouto, the focus had shifted entirely away from the simulated villains.
It started with the way the sun caught the sweat-slicked line of Katsuki’s jaw as he propelled himself through the air. Every explosion was a strobe light, illuminating the determination etched into his features.
Shouto found himself lingering a split second too long on the way Katsuki’s hero suit strained against his shoulders or the way his breath came in huffs that Shouto could practically feel against his own skin even from yards away.
By the time they reached the cooling-off period, Shouto was operating on autopilot. His ice was sluggish, his fire flickering with a lack of intensity that he couldn't quite master.
"What the hell is wrong with you?" Katsuki’s voice sliced through the humid air of the service corridor.
Shouto blinked, realizing he had been staring at the pulse point in Katsuki’s neck for a solid thirty seconds. "Nothing."
"Bullshit," Katsuki snapped, stopping dead in his tracks. He spun around, his eyes narrowed and sparking with genuine confusion. "You’ve been trailing me like a lost dog all afternoon. You missed three openings in the last drill because you were too busy looking at…what? My boots? The back of my head? Spit it out, Half-and-Half."
Katsuki stepped closer, his bravado masking a flicker of uncertainty. He wasn't used to Shouto being quiet. He was used to the challenge, the icy stoicism, or the occasional blunt remark. This heavy, weighted silence was new, and it made the hair on the back of Katsuki’s neck stand up.
"You're acting weird," Katsuki muttered, his voice dropping as he searched Shouto’s face for a sign of a prank or a hidden injury. "Are you concussed? Did you take a hit to the head when that wall came down?"
Shouto looked at him and saw the smudge of dirt on Katsuki’s cheek and the way his blonde hair was plastered to his forehead. The confusion in Katsuki’s crimson eyes was so earnest it made Shouto’s chest ache with a sudden possessiveness.
"I’m not concussed," Shouto said, his voice dropping an octave. He took a step forward, closing the gap until the heat from their training suits began to mingle. "I just realized I haven't been paying enough attention to the right things."
Katsuki recoiled slightly, his brow furrowing. "The hell does that mean? The 'right things' are the villains, you moron. We’re supposed to be heroes, not—"
"Kacchan? Todoroki?"
The sound of Midoriya’s voice echoing from the far end of the hallway acted like a physical jolt. Katsuki’s eyes widened, his instinct to avoid a lecturing session overriding his confusion.
"Great. The nerd's here," Katsuki hissed. He looked over his shoulder toward the end of the hallway where the sound of Midoriya’s endless mumbling and Iida’s chopping hand motions were getting louder. "If they see us standing here like a couple of idiots, we’re never gonna hear the end of it."
Katsuki started to move, ready to bolt toward the opposite stairwell, but a firm hand caught his wrist. The touch was suddenly searingly hot on one side, bracingly cold on the other.
"In here."
Shouto didn't wait for an argument. He stepped back, pulling a heavy metal door open with his free hand. It was a maintenance closet, barely larger than a phone booth and stacked high with industrial-sized mops and crates of floor wax.
Katsuki blinked, his brow furrowing in genuine confusion. "The hell? A closet? Just tell ‘em to get lost, Half-and-Half. Why are we hiding like—"
"Get in, Katsuki." Shouto’s voice was uncharacteristically low, lacking its usual airy detachment.
Before Katsuki could snap back with a retort about being ordered around, Shouto maneuvered him inside. The space was so cramped that Katsuki stumbled back, his shoulder blades hitting the far wall with a dull thud. Shouto followed him in, the door clicking shut behind them with a finality that made the air feel twice as heavy.
The darkness was absolute.
"What is wrong with you today?" Katsuki’s voice was a harsh whisper, vibrating in the small space. He couldn't see Shouto’s face, but he could feel the radiating heat from the boy’s left side. "First you’re staring at me all through training like I’m about to sprout a second head, and now you’re dragging me into a cleaning closet. If you’re sick, go to Recovery Girl and stop acting like a creep."
Katsuki reached out, intending to shove Shouto’s chest and find the door handle, but his hand landed on the rough fabric of Shouto’s hero suit. Beneath it, he felt the thrum of a heart racing far too fast for a "calm" person.
"Katsuki," Shouto’s voice was right against his ear, his breath hitching.
"What?" Katsuki’s voice was smaller now, his confusion finally turning into electric tension.
"I wasn't staring because you were doing something wrong," Shouto breathed. In the dark, his hand found Katsuki’s elbow. A soft, deliberate brush of fingers that sent a jolt straight through Katsuki’s spine.
Katsuki froze. He’d expected an insult, a technical critique, or even a challenge to a spar. He hadn't expected the slow, agonizingly careful way Shouto’s fingers began to trail upward, claiming the skin of his arm.
"I was staring because I couldn't look at anything else."
The confusion in Katsuki’s mind didn't stand a chance. It dissolved in an instant, replaced by a heat that had nothing to do with Shouto’s quirk and everything to do with the way he was currently being pinned against a stack of towels.
The closet smelled of stale floor wax and the metallic tang of Katsuki’s own rising heat. It was a cramped, suffocating space. The kind of place where every breath felt shared and every movement was a gamble.
Katsuki’s back was pressed hard against the metal doorknob, the cold brass digging into his spine, but he barely felt the discomfort. All his senses were hyper-tuned to the boy standing inches away. It was a terrifying paradox: Bakugou Katsuki, the man who was meant to be the absolute apex, the one who took what he wanted and yielded to no one, was vibrating with a vulnerability that felt like a physical weight.
All it took was one touch.
It started as a soft brush of fingers against his elbow. A feather-light contact that shouldn't have meant anything. But as Shouto’s hand trailed higher, sliding up his thigh with a slow, agonizing deliberation, Katsuki felt his composure dissolve like sugar in a storm. His resolve, usually a fortress of iron and ego, shattered like glass hitting a marble floor.
Shouto’s eyes bore into him, dual-colored and maddeningly steady. There was no mockery in that gaze, only a quiet, burning intensity that made Katsuki feel like he was being dismantled piece by piece. Shouto’s touch was gasoline on an open fire. It didn't just warm him; it consumed him, blurring the edges of his own identity until he didn't know where he ended and where Shouto began.
The power dynamic had shifted, and the realization was daunting. Katsuki marveled at how easily he’d fallen. He’d spent his whole life building walls, perfecting his blast, and ensuring he was untouchable. Yet, here he was, completely helpless because of a few inches of skin contact.
He couldn’t imagine this with anyone else. The thought of another person’s hands sliding up his shirt or another set of lips leaving a mark on his skin made his stomach turn with a sudden, violent possessiveness. This specific tension belonged to them. He wanted it all to himself, a secret war fought in the dark of a supply closet.
“What are you thinking about?”
Shouto’s voice was a low vibration that settled in the marrow of Katsuki’s bones. His breath was hot against the sensitive skin of Katsuki’s neck, a precursor to the sudden sensation of teeth gently nipping at the hollow of his throat.
Katsuki’s head hit the door with a soft thud. His hands, which usually sparked with lethal precision, were trembling as they found purchase in the fabric of Shouto’s uniform. He tried to summon a snarl, a biting insult, to regain some semblance of control, but all that came out was a broken huff of air.
The air in the closet had grown thick, the oxygen seemingly replaced by the electric weight of their proximity. Katsuki’s lungs felt tight, every inhale a struggle against the scent of Shouto. That clean, crisp winter air mixed with a slow-burning heat that was uniquely his.
“You’re...mine.”
The words didn't come out with his usual explosive bravado. Instead, they were shredded and dragged through the gravel of his throat. Katsuki’s pride, usually a towering monument, was currently a ruin. He felt exposed, his skin oversensitive to the point of agony, and yet he couldn't stop reaching.
“I want to...own you,” he managed to finish, his voice cracking on the final word.
It was a confession that should have felt like a defeat. To want to possess someone so completely was to admit they had a hold on you that you couldn't shake. It was a truth laid bare in the dark, and the vulnerability of it made his heart hammer against his ribs like a trapped bird.
A low, huffed breath that might have been a laugh brushed against Katsuki’s ear.
“From someone in your position, that’s funny.”
Shouto’s voice was smooth, a stark contrast to Katsuki’s state. His hand didn't stop its ascent, sliding farther up under the hem of Katsuki’s shirt. The calloused palm grazed the sensitive skin of his stomach, and Katsuki let out a sharp, choked gasp. His spine pressing so hard against the door that the metal groaned. He was holding himself up by force of will, his muscles coiled and trembling.
Shouto was teasing him by playing with the explosive temper of the class’s most volatile student as if he were nothing more than a flickering candle. It was a power play, and Katsuki was losing. The realization was terrifying, but beneath the fear was a rush of pure, unadulterated adrenaline. Being defenseless was a new kind of high.
“You’re mine, too,” Shouto continued, his tone shifting from playful to something much darker and much more possessive.
He moved with a slow, predatory grace, trailing a path of searing kisses down the line of Katsuki’s jaw. Each touch felt like a brand, a permanent mark that claimed territory. Katsuki’s eyes drifted shut, his head falling back against the door as he let out a shuddering breath.
“I’ll belong to you,” Shouto whispered against his skin, his teeth suddenly grazing the junction where his neck met his shoulder, “if you belong to me.”
Then, he bit down.
It wasn't a nip this time. It was a firm, grounding pressure that sent a lightning bolt of sensation straight to Katsuki’s core. His knees finally betrayed him, buckling under the weight of his own desire. He began to slide down the door. His strength evaporated, but he never hit the floor.
Shouto’s other arm hooked firmly around his waist, pulling him flush against a chest that felt like a furnace. He held him there suspended, caught, and utterly claimed.
Katsuki fisted his hands into the front of Shouto’s shirt, his knuckles white. He was a hero who was supposed to win every fight, but as he clung to the boy holding him upright in the dark, he realized he’d never felt more powerful than in the moment he finally let himself be caught.
The closet felt like it was shrinking, the air displaced by a heat so volatile it threatened to trigger the overhead sprinklers. Katsuki’s head thudded back against the metal door again and again, a punctuation to the wreckage Shouto was making of his composure.
He tried to speak. He tried to summon his pride, but it had been swallowed by the relentless pressure of Shouto’s mouth.
“Marks,” Katsuki gasped, the word barely a puff of air. “There’ll…be marks.”
He could feel them blooming like dark flowers across his skin. Shouto was being thorough. He was marking the hollow of Katsuki’s throat, the sensitive cord of his neck, and the sharp edge of his jawline with a predatory focus.
Tomorrow, the high collar of his uniform wouldn't be enough to hide the evidence of this theft. The entire class would see the blue-black blossoms of Shouto’s hunger, and the thought should have infuriated him. It should have made him blast his way out of this confined space.
Instead, it made his blood sing.
“Shou—”
The name was cut short, stolen right out of his mouth. Shouto leaned in, capturing Katsuki’s lips in a kiss that tasted of salt and desperation. It wasn't soft. It was a collision. A molten, tongue-searing invasion that turned Katsuki’s internal temperature into something lethal. The heat spread, liquefying his bones until the only thing keeping him vertical was the friction of their bodies pinned together.
“Fuck,” Katsuki breathed into the narrow space between their lips, his voice shaking with a terrifying lack of air. “Fuck. What are you…what are you doing?”
Shouto pulled back a fraction, his eyes dark and clouded with a rare, unbridled possessiveness. “Marking my territory.”
Then, he bit down again harder this time, right on the sensitive slope where Katsuki’s shoulder met his neck.
Katsuki properly lost his mind. A white-hot jolt of sensation careened through his nervous system, and he let out a sound he would deny to his dying breath: a wrecked, needy whimper.
The denial was gone. The ego was a smoldering ruin. The undeniable truth was that he belonged to Shouto, not just in this dark corner but in the way his heart only seemed to beat in time with the other boy's and in the way his fire only ever cooled for this specific touch. He was owned, conquered, and claimed in more ways than he could ever count.
But as Katsuki’s fingers dug into Shouto’s shoulders, he felt it. The slight tremor in Shouto’s hands and the thundering pace of a heart against his own chest. Shouto wasn't the calm victor he pretended to be. His fingers, though gentle as they trailed soft kisses over the marks he’d made, were vibrating with an impatience that matched Katsuki’s own.
They were both drowning. They were a pair of idiots, trapped in a cleaning closet while the rest of the world went on without them, burning themselves alive in a fire they’d started together.
Katsuki pulled Shouto’s face back to his, his eyes narrowed but gleaming with a fierce, redirected pride. If he were going down, he would be taking Shouto with him.
“Don't stop,” Katsuki hissed, his grip tightening. “If I'm yours, then you’re goddamn well mine. Finish what you started.”
“Not here,” Shouto rasped against Katsuki’s lips, the words vibrating with a restraint that sounded physically pained. “Someone will come back for a mop. Or Iida will start a search party.”
Katsuki let out a frustrated half-growl, half-groan, but he didn't argue. He couldn't. His knees were still trembling from the bite on his shoulder, and the idea of being walked in on by Deku or Kirishima while he looked this undone was the only thing capable of clearing the fog in his brain.
They moved through the corridors like ghosts, or perhaps like predators. Katsuki kept his head down, his jacket zipped all the way to his chin to hide the blooming heat on his neck. Every time their shoulders brushed in the narrow stairwell, a fresh spark of adrenaline shot through him.
When they reached the heights of the 3-A dorms, Shouto didn't hesitate. He turned the knob, pulled Katsuki inside his room, and clicked the lock with a definitive snap that echoed in the quiet space.
Shouto’s room was a sanctuary of traditional tatami mats and the scent of clean cedar. But, the peace of the aesthetic was immediately shattered by the way Shouto turned on him.
He didn't say a word. He walked into Katsuki’s space, his dual-colored eyes dark with a hunger that he had finally stopped trying to mask.
Katsuki backed up near Shouto’s futon. He felt a momentary flash of his usual defiance, the urge to shout, to reclaim the lead, but it died the moment Shouto’s hands found his waist again.
“You said to finish it,” Shouto reminded him, his voice low and steady. He wasn't teasing anymore. The playfulness from the cloak had been replaced by a heavy, grounding sincerity.
“I didn't stutter, Shouto,” Katsuki barked, though his voice lacked its usual bite. He reached up, his shaking fingers tugging at the collar of Shouto’s uniform. “You want to own me? You want to mark me? Then do it. But don't think for a second I’m going to lie here and just let you easily.”
Shouto leaned down, pressing Katsuki back onto the futon. The change in setting didn't dampen the intensity; it only gave them more room to burn. Shouto’s hand slid from Katsuki’s waist to his chest, feeling the explosive rhythm beneath his ribs.
“I know,” Shouto whispered, his lips grazing the mark he’d left on Katsuki’s jaw earlier. “That’s why I want you. Because you never go down without a fight.”
Katsuki’s eyes flared, a smirk finally tugging at the corner of his mouth despite the heat rising in his cheeks. He wrapped his arms around Shouto’s neck, pulling him down until there was no air left between them.
“Good,” Katsuki hissed. “Then give me everything you’ve got.”
The shift from the cramped energy of the closet to the quiet stillness of Shouto’s room was jarring. The scent of clean cedar and traditional tatami mats usually acted as a grounding force, but tonight, the air felt charged with a different kind of electricity.
Shouto’s hands, one warm and one cool, slid beneath the hem of Katsuki’s shirt, tracing the ridges of his ribs with an almost reverent touch. Katsuki let out a broken gasp as he was pressed back onto the futon. The change in position was a physical manifestation of his surrender. He was flat on his back, looking up into Shouto’s dual-colored eyes, feeling the weight of the other boy settling between his thighs.
The kisses weren’t soft anymore. They were hungry, deep, and punctuated by the sensation of Shouto’s teeth finding the sensitive skin of Katsuki’s collarbone. Katsuki arched off the mats, his fingers curling into the sheets as a white-hot jolt of pleasure careened through his nervous system.
“Shouto,” he rasped, the name coming out as a plea he’d never admit to.
Shouto moved, his focus entirely on the person beneath him. He was thorough, marking the pale skin of Katsuki’s chest and stomach as if mapping out a territory he intended to keep. When his fingers moved to the waistband of Katsuki’s pants, the blonde’s eyes flared, his chest heaving with the effort to maintain some semblance of control.
“I’ve wanted this,” Shouto whispered against his skin, his voice thick with a rare, raw honesty. “I’ve wanted to see you like this for so long.”
Shouto didn’t rush. He braced his weight on his forearms, his eyes locked onto Katsuki’s with a focus that was borderline predatory.
Slowly, with a steady pressure, Shouto began to push inside after prepping Katsuki's tight hole. Katsuki’s head thudded back into the pillow, a wrecked, high-pitched gasp escaping his throat as his muscles stretched to accommodate the intrusion.
It was an overwhelming invasion of his space, his body, and his pride, and he loved every second of it. He felt Shouto slide deeper, inch by relentless inch, until he was buried completely within him, bottoming out with a heavy, grounding thud that seemed to echo in Katsuki’s very marrow.
"Oh fuck, Shou."
Katsuki let out a dry laugh, though it sounded more like a sob. He wrapped his legs around Shouto’s waist. The friction of skin against skin was like a match to dry brush, igniting a fire that neither of them seemed capable of putting out.
As Shouto’s weight pressed him further into the mattress, the springs groaned softly. The fabric of the sheets felt like ice against Katsuki’s overheated skin, a grounding contrast to the slick, searing heat of Shouto’s body. Every slide of a thigh, every brush of a chest against his own, sent a fresh jolt of electricity through Katsuki’s overstimulated nerves.
Shouto’s touch remained steady and firm, a masterful guidance through the suffocating haze of heat and adrenaline. He moved with a quiet confidence, his hands mapping the curve of Katsuki’s waist and the dip of his hip with an ownership that felt ancient.
It was a conversation without words, a push and pull of power that Katsuki found himself relishing. He had always defined power by who was standing at the end of a fight, but this was different. He was the one being taken, the one being claimed, pinned beneath a boy who usually looked at the world with icy indifference.
Yet, the way Shouto looked at him now with a mixture of worship and starving hunger made Katsuki feel more powerful than he ever had on a battlefield.
To be the sole object of that much intensity was a high he couldn't have imagined. Katsuki’s heels dug into the mattress, his back arching as Shouto’s mouth found the sensitive cord of his neck again, marking him with a persistence that promised bruises by morning.
As the tension reached its peak, the room blurred into a smear of shadow and cedar. Katsuki’s world narrowed down to the hitching sound of Shouto’s breathing and the feeling of being completely, utterly possessed. He could feel the fine tremors in Shouto's muscles, the effort it took for the other boy to keep from shattering completely.
Katsuki fisted his hands into the bi-colored strands of Shouto’s hair, tugging with an aggressive desperation that forced Shouto’s head down. He met him in a kiss that tasted of salt, sweat, and a mutual obsession that had been simmering for months. It was a collision of teeth and tongues, a desperate attempt to swallow the sounds they were both making into the quiet of the dorm room.
In that moment, there was no Class 3-A and no Pro-Hero rankings. There was only the weight of Shouto above him, the mattress beneath him, and the undeniable truth that they had finally burned everything else away.
The silence that followed was heavy, filled only by the sound of two hearts trying to find a shared rhythm.
Katsuki lay there, his skin damp and marked with the evidence of Shouto’s hunger, feeling a hollowed-out peace. He turned his head, looking at the boy who had finally managed to do what no villain ever could: he had conquered him.
“You’re an idiot,” Katsuki whispered, though there was no heat in it.
Shouto pulled back enough to look him in the eye, a genuine smile tugging at the corners of his mouth. “But I’m your idiot.”
Katsuki snorted, reaching up to clumsily swipe at Shouto’s hair. “Yeah. You better be.”