Chapter 1: Jealousy Burns Hotter Than Nitroglycerin
The sweat drying on Katsuki’s skin was the only proof he’d been training at all. The agency gym was empty, the digital clock glowing 23:47 in the red dark. He should have left hours ago. Instead, he was perched on a weight bench, phone gripped tight enough to warp the case, watching the replay for the third time.
It was some inane daytime interview. Deku, the Symbol of Peace’s shiny successor, sitting on a pastel couch, smiling that stupid, earnest smile. Talking about unity, about hope. Katsuki’s thumb hovered over the screen, pausing the video just as Deku leaned forward to accept a glass of water from the host.
There. Just there.
A blur of purplish-blue, a faint but distinct smudge against freckled skin, peeking from beneath the crisp white collar of his hero suit. A hickey. His hickey. Bitten into the junction of Deku’s neck and shoulder two nights ago in a frantic, silent clash against the door of Katsuki’s own apartment.
The memory hit him like a physical wave—the sharp, clean scent of Izuku’s shampoo cutting through the ozone and burnt sugar of his own sweat. The choked-off gasp, not of pain, but of raw, shocking want, when Katsuki’s teeth had broken skin. The way Izuku’s body had arched, all powerful muscle yielding, his own hands fisting in Katsuki’s spiky hair to hold him there, to demand more. The frantic, unspoken race that followed, a battle of a different kind, all grasping hands and torn fabric and the slick, hot slide of—
“Looks painful.”
Katsuki jerked, his quirk sparking in his free palm with a sharp pop-crackle. The phone screen went black. He didn’t need to turn to know the shitty-haired bastard leaning in the doorway, a shit-eating grin plastered across his face.
“The fuck do you want, Kirishima?” Katsuki’s voice was gravel, low and dangerous.
Eijiro pushed off the doorframe, walking in with his hands in his pockets, deliberately casual. “Just checking on my bro. You’ve been MIA for two days. Missed the debrief. Again.” He stopped beside the bench, his eyes flicking to the dead phone in Katsuki’s hand. “Healing nicely, is it?”
“Shut up.”
“I mean, it’s pretty strategic placement.” Kirishima’s tone was light, teasing, but his eyes were sharp. “Just under the collar. Easy to hide. Unless you’re leaning forward on national TV. Then it’s just… a hint. For the really observant fans.”
Katsuki stood up, the movement violently abrupt. “I said shut it.”
“Or what? You’ll blow me up?” Kirishima chuckled, nodding toward the bank of security monitors on the far wall, currently cycling through live feeds from the agency’s public lobby. One feed was frozen, paused. It was a still from the same interview, blown up and crystal clear on the 50-inch screen. Deku’s paused, smiling face. The mark on his neck, undeniable.
Katsuki’s breath hitched. He hadn’t even realized he’d routed the feed, hadn’t remembered pausing it. He’d just been staring.
Kirishima saw the trajectory of his gaze. The grin widened. “Yeah. That’s what I thought. So it’s like that, huh? You and the number one. A little possessive game. You mark him up where everyone can almost see, and he… what? Lets you? Wears it like a badge?”
Something primal and white-hot snapped behind Katsuki’s ribs. It wasn’t just the teasing. It was the accuracy. The exposure. The sight of that private, brutal claim displayed for anyone with access to the security server to see. For Kirishima to see and understand.
“SHUT IT, SHITTY HAIR!”
The explosion wasn’t a conscious decision. It was pure, unmediated reaction. A blast of concussive heat and fury erupted from his palm, not aimed at Kirishima, but across the room. It struck the center of the monitor with a deafening BOOM. The screen erupted in a shower of glass and plastic and sparks, the image of Izuku’s face fragmenting into a thousand glowing pieces before going dark, wires spitting and curling like dying snakes.
Silence roared in the aftermath, thick with acrid smoke and the alarm beeping of a triggered fire suppression sensor. Kirishima stood perfectly still, his grin finally wiped clean, replaced by wide-eyed shock.
Katsuki’s hand smoked. His chest heaved. He stared at the ruined monitor, at the destruction he’d caused in a single, uncontrollable second. Not at an enemy. At a screen. At an image.
He’d never felt more exposed.
Without a word, he turned and stalked out of the gym, leaving Kirishima amidst the wreckage and the truth, which now hung in the air, as tangible and charged as the smell of burnt plastic and ozone.
Without a word, he turned and stalked out of the gym, leaving Kirishima amidst the wreckage and the truth, which now hung in the air, as tangible and charged as the smell of burnt plastic and ozone.
The hallway was too bright, sterile. His boots echoed like gunshots. He just needed to get to the roof, to the open air, to fucking scream until his lungs bled. He shoved the stairwell door open with a bang, taking the steps two at a time.
And collided with a solid wall of muscle at the first landing.
“Kacchan?”
Izuku. Fucking Izuku. In his stupid green hoodie, hair a mess, holding two paper cups of coffee. One of them sloshed hot liquid over Izuku’s wrist, but he didn’t even flinch. His wide green eyes were just concerned, scanning Katsuki’s heaving chest, his smoking hand, his face.
The sight of him, here, now, with that goddamn mark probably still visible under his collar, short-circuited every rational thought in Katsuki’s head. The fury had no target, so it chose the only one it ever truly recognized.
“You,” Katsuki snarled, his voice a low, vicious thing.
Izuku blinked. “Me? What’s wrong? Were you training—”
“Fucking think you’re clever?” Katsuki stepped into his space, forcing Izuku back against the cold concrete wall. The remaining coffee cup crumpled between them. “Strutting around. Letting everyone see. That some kind of fucked-up declaration, you pathetic nerd?”
Izuku’s face cycled from confusion to dawning, frustrated understanding. His own temper, usually so carefully banked around Katsuki, showed in the tight line of his jaw. “Letting everyone see what? What are you even talking about?”
“You know exactly what I’m talking about!” Katsuki’s finger jabbed toward Izuku’s neck, stopping just short of touching the skin he’d bruise. His own pulse hammered in his ears. “You wore that suit on purpose. Leaned forward on purpose. You want them to know? You want them to see what I did to you?”
The air crackled. Izuku’s eyes darkened, not with fear, but with a challenge that made Katsuki’s blood burn hotter. “Maybe I just don’t care about hiding it,” Izuku said, his voice quiet but steady. “Maybe it’s not about them at all.”
That was worse. That was so much worse. It implied something real, something that existed outside of their secret, brutal games. It threatened to name the thing that terrified Katsuki most.
“Fuck you,” Katsuki spat, the words hollow. He couldn’t breathe here, with him. “You’re a walking liability. A distraction. Stay the hell out of my way.”
He shoved past him, shoulder-checking him hard, and took the stairs down instead of up, needing to put concrete and distance between them. Needing to run.
Izuku stared after him, his chest tight. The accusations were gibberish, layered over a truth Izuku could feel but couldn’t parse. He looked down at the smashed cup at his feet, the brown pool spreading. He took a slow breath, then continued up the stairs. He’d been heading to the third-floor analysts’ office anyway.
The door to the agency gym was ajar. A faint wisp of smoke drifted into the hall. Izuku paused, his hero instincts kicking in before his personal ones. Fire? Electrical fault?
He pushed the door open slowly.
The scene was one of contained destruction. One monitor was a shattered, blackened hole in the wall. Tiny cubes of safety glass glittered across the mats. In the center of it stood Kirishima, arms crossed, staring at the wreckage with a deeply perplexed frown.
“Kirishima?” Izuku stepped inside, the door sighing shut behind him. “What happened? Are you okay?”
Kirishima jumped, turning. “Deku! Hey. Yeah, man, I’m fine.” He rubbed the back of his neck, his sharp teeth worrying his bottom lip. “Just… some equipment malfunction. Super intense.”
Izuku’s eyes moved from the specific, explosive damage pattern on the monitor to Kirishima’s uncharacteristically evasive face. He remembered Kacchan’s smoking palm. The fury that seemed to have no source. The coffee dripping down his own wrist.
“A malfunction,” Izuku repeated softly, walking further into the room. His eyes caught on the security system’s main console. The other monitors showed various live feeds—the lobby, the front gate, the commissary. One feed, the source for the destroyed screen, was blank and error-coded.
But the system had a memory cache.
Almost without thinking, Izuku reached over and tapped a few keys, pulling up the last recorded image from that feed before its destruction.
His own face, frozen in mid-smile, filled the adjacent monitor.
He stared. The high-definition capture was merciless. He saw the faint shadow of fatigue under his eyes from a week of poor sleep. He saw the way his collar gaped just slightly from the movement of leaning forward.
He saw the bruise. A lurid, beautiful purple against his skin, clear as a fingerprint.
Heat flooded his face, then drained away, leaving him cold. He understood Kacchan’s rage now. The shattered screen. The storming out. It wasn’t about Izuku showing off. It was about Katsuki being seen. About losing control of the narrative. About someone else knowing.
Kirishima was silent behind him. The tension in the room was thick enough to taste.
Izuku finally turned, meeting his friend’s eyes. Kirishima’s expression had shifted from confusion to a pained, awkward understanding.
“So,” Kirishima said, his voice uncharacteristically gentle. “You and Bakugou, huh?”
Izuku looked back at the ruined monitor, at the digital ghost of his own marked skin. He had no answer that wouldn’t be a lie. The truth was a bomb between them, already detonated.
Kirishima sighed, a long, heavy sound. “Man, he’s gonna be a nightmare about this.”
Izuku finally found his voice, quiet and resigned. “He already is.”