Okay hear me out. After watching the KARMA trailer, I can’t stop thinking about Changbin as an underground boxer. He’s all tough and quiet, throwing punches like he’s trying to outrun something heavy. Maybe he’s doing it for the money, to protect someone, or just because it’s the only thing that makes him feel in control.I was thinking it’d be interesting if someone(reader) outside the ring slowly starts to get through to him,maybe a medic who patches him up after fights, or someone who stumbles into his world and doesn’t back down. They have this push-and-pull dynamic, emotionally conflicted because neither of them is really ready for a relationship, even though the tension is there.Also, I thought it could also be fun to throw in a boxing “rival” who’s into her too and tries to steal her away, just to make things messier.(This is a little extensive but I couldn’t bring myself to actually think about the plot so I hope your amazing brain makes use of this.)
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Pairing: Boxer! Changbin x Medic!femReader
Word Count: 4399
Summary: By day you’re a doctor, but by night you stitch together the broken bodies of underground fighters in Seoul. That’s where you meet Seo Changbin, a boxer whose fists and silence have made him a legend. Yet under your care he begins to soften, to share pieces of the boy who once dreamed of music. As you patch his wounds and stand against his demons, you two grow closer than either of you thought possible.
Warnings/Tags: Physical violence (boxing/underground fights, beatings), blood and medical procedures (stitches, wounds), forced labor / exploitation / threats / intimidation by a trainer, emotional trauma and references to death (an off-screen friend’s fatal injury), slow af burn (wait for chapter 2😂😭), boxer!changbin, medic!reader, comfort, angst
A/N: Loved working on this. There will be a second chapter next week🖤 I hope you guys enjoy it. Thank you for your request 🎀-anon🖤
Seoul’s nights had their own kind of heartbeat. Somewhere between the flicker of neon signs and the narrow alleyways too dark for law to crawl into, it throbbed. A muffled rhythm of fists meeting flesh, the roar of voices demanding blood and victory, the bills exchanging hands faster than morals could keep up. The underground boxing rings were never advertised, but everyone who needed to know knew. Smoke hung thick in the air, beer spilled sticky onto concrete floors, and the crowd pressed shoulder to shoulder around the crude square made of ropes. Here, rules bent until they broke. No gloves, no rounds, no mercy. Just fists, sweat, and survival. And yet, despite the chaos, one constant had begun to emerge. You.
A doctor by day, threading needles through torn skin under sterile lights, patching up children with fevers or men with bad backs. But once the sun fell, you became someone else. Not quite legal, not quite criminal, a quiet fixture in the boxing world. Fighters found their way to you after matches, bloodied and bruised, limping into the cramped backroom you had claimed as your own. Word had spread quickly: the woman who didn’t ask questions, who stitched wounds cleaner than anyone else, who never judged. You were fast becoming indispensable.
Which was exactly why you were there tonight, leaning against a scarred wooden table cluttered with gauze, disinfectant, and sutures, waiting for the inevitable knock on your door. The crowd outside roared louder, signaling the next fight. You peeked through the small crack of the backroom door, catching sight of him for the first time.
Seo Changbin. Even among the sea of fighters, he stood out. Broad-shouldered, compact, built like a wall that moved with terrifying speed. His reputation preceded him — one of the best in the underground circuit, a man who took down opponents twice his size, fists like hammers, eyes like steel. People bet heavy on him, knowing he rarely disappointed.
The bell clanged, sharp and ugly, and the fight began. You watched, unable to look away. His movements weren’t wild, but precise. Every punch had weight, every step purpose. He absorbed blows to deliver harder ones back, his body swaying with the rhythm of the fight. But even the best bled eventually. A hook slipped past his guard, catching him hard along the cheekbone, splitting skin. Blood welled, fast and hot, painting his face as the crowd howled for more.
It ended not long after. His opponent collapsed in a heap, lungs wheezing, unable to rise. The ringmaster lifted Changbin’s arm in victory, but you could see it: the way he touched his side, subtle but telling, the crimson streak down his jaw.
Minutes later, your door creaked open. He stood there, slightly hunched, the ferocity of the ring replaced with a hesitant silence. Up close, he was different. Not the beast the crowd had screamed for, but a young man. His lashes were long, his jaw sharp even under the swelling bruise, and his lips pressed tight as though he wasn’t used to asking for help.
“Sit,” you said softly, gesturing to the chair. He obeyed without a word, his shoulders tense as though he’d rather be anywhere else. You cleaned the cut on his cheek first, dabbing gently as he flinched. He didn’t speak, didn’t complain, just watched you work with dark eyes that seemed far too serious for someone his age.
“You’re lucky it’s not deeper,” you murmured, threading the needle. “Could’ve used stitches, but you’ll get by without them. Keep it clean.”
Silence. Then, a faint hum of acknowledgment.
Your gaze drifted to his torso, where the fabric of his shirt clung damp with sweat and dark stains of blood. “Lift your shirt,” you instructed.
For a moment, he hesitated. Then, with a reluctant motion, he obeyed. Your breath caught before you could stop it. His body was as powerful as his reputation suggested, muscle carved into muscle, but what struck you more were the bruises blooming across his ribs, already turning a sickly purple. “Does it hurt to breathe?” you asked, pressing lightly. He winced, the first sound he’d made — a low hiss between clenched teeth. “Thought so. Might be a cracked rib. Nothing I can fix here, but I can wrap it to help you move until you decide to see a real doctor.”
His lips twitched, almost a smile, but not quite. “You’re real enough.” His voice was deeper than you expected, but quiet, like he didn’t use it often.
You focused on wrapping his torso, careful with every tug and tie. You were too aware of him — the heat of his skin under your hands, the way he kept still, respectful, almost shy despite his world of violence. When you finally tied the bandage off, you glanced up. He was watching you, eyes unreadable. “All done,” you said gently, forcing a smile to your lips. “You’ll live.”
For the first time, his expression softened. His gaze flickered down, and he whispered, “Thank you.” It was so quiet you almost missed it.
You smiled, the kind that reached your eyes this time, and waved him toward the door. “Go on. They’ll want their champion back.”
He stood slowly, giving you one last glance before stepping into the shadows of the hall. The crowd’s roar swallowed him up again, but the echo of his quiet gratitude stayed behind, humming warm in your chest.
-
It wasn’t the last time you saw him. In the weeks that followed, Changbin came back to your little backroom more than once. Sometimes with blood on his knuckles, sometimes with bruises swelling dark against his ribs, sometimes barely scratched at all. But each time he came, he sat in the same chair, shoulders stiff and words few, letting you patch him up like it was routine.
If anything, the silence between you became its own kind of language. You learned the way his jaw clenched when disinfectant stung, the slight twitch of his fingers when your hands lingered too long over a bruise, the way he dipped his head just enough to murmur a quiet “thanks” before leaving.
It was after his third fight since your first meeting that the silence cracked. You were swabbing a cut above his eyebrow, concentration narrowed to the thin line of blood, when he asked, his voice low: “How’d you end up here?”
You blinked, caught off guard. Usually he said nothing beyond the bare minimum. Meeting his dark eyes, you hesitated — but there was something in them, a quiet pull, that made you answer. “About a year ago,” you began, setting the cotton aside, “I lost a good friend to one of these fights. He collapsed in the ring. They called it exhaustion, but it wasn’t. He bled out internally, and no one here knew how to stop it. No medic, no help. Just people screaming for the next fight while he…” Your throat tightened, but you forced yourself to finish. “I swore that wouldn’t happen again. Not if I could do anything about it.”
His breath hitched, barely audible. For a second, he wasn’t the stoic fighter in front of you but just a man remembering something he wished he could forget. His jaw flexed, his gaze dropping to the floor. You knew then that he remembered. That he had seen it too. “What makes you stay in such a horrible place?” he asked, voice rougher than before.
You tilted your head, studying him. “That’s my question for you. Isn’t this a horrible environment to you as well?”
Pain flickered in his eyes. It wasn’t obvious, but it was there — quick and raw, before he managed to push it down again. He gave a small, bitter huff of a laugh, shaking his head. “It is. It only destroys people.”
You set the needle down and frowned, searching his face. “Then why are you here?”
For the first time since you’d met him, his body stiffened in a different way. His lips parted, but he shook his head firmly, like slamming a door shut. “I shouldn’t talk about that.”
Your brows furrowed. “Are you…kept here against your will?” The question hung heavy in the air. He didn’t move, didn’t speak — just stared at the floor, silent for what felt like forever. The tension twisted in your chest, but you didn’t push. You simply waited.
Finally, his eyes lifted to yours, something unreadable swimming in the dark of them. His voice was quiet, careful. “What are you doing in two days?”
You blinked. “I’m off work. Why?”
He hesitated again, then reached for the scrap of paper you always used for notes on medicine and care. Pulling a pen from your table, he scribbled down an address, his handwriting quick and slanted. When he handed it back, his fingers brushed yours, deliberate or not you couldn’t tell. “Come by. After my training.”
You looked at the paper, then at him. “What for?”
He didn’t answer. Just pushed himself up from the chair, still moving a little stiffly from the blows he’d taken. His gaze lingered on you for a long moment before he finally muttered, “You’ll see.” And then he was gone, leaving only the faint smell of sweat and antiseptic in the room, and the scrap of paper burning warm in your hand.
-
The gym was tucked into a side street, its windows fogged from the warmth inside. You hesitated at the door, the low hum of a speed bag thudding rhythmically against leather guiding you in. Inside, Changbin was in the ring. He moved differently here; not for an audience, not for the roar of gamblers, but for himself. Focused, every punch measured against the silence. Sweat ran down his temple, his muscles taut beneath his shirt as he ducked and swung, breathing rough but steady. You leaned against the wall, watching.
He noticed you the moment he paused to unwrap his hands. A flicker of something passed through his expression — surprise, then something softer, almost relieved. With a brief nod, he disappeared into the locker room, leaving you alone with the smell of chalk and leather. When he came back, hair damp from a quick shower, he lingered by the doorway before walking toward you. His eyes met yours, hesitant but earnest, and then he smiled shyly. “Hey,” he murmured. “Do you…want to grab dinner? There’s a place nearby.”
Your brows lifted. “Oh? So this was a date all along?”
Color rushed up the curve of his ears, creeping to his cheeks. He looked away, muttering, “You wanted answers. That’s what you’ll get.”
You couldn’t help but grin, nodding as you fell into step beside him. Dinner ended up being simple street food — tteokbokki and skewers, hot enough to burn your tongue, eaten straight out of their paper wrappings as you walked toward the Han River.
By the time you found a bench overlooking the dark sweep of water, the city lights glinting off its surface, he’d grown quieter again. He sat beside you, elbows resting on his knees, food container balanced loosely in one hand. “You can ask now,” he said at last, his voice low, almost lost to the breeze.
You turned toward him. “How did you end up in all this?”
For a long while, he said nothing. Then, slowly, he began. “Back when I was a teenager, I had this huge fight with my family. I was stupid, angry…I thought running away would fix things.” His jaw tightened. “I wandered the streets for days. No money, no place to sleep. And then I met him. My trainer.” He paused, staring at the river. “He gave me food, a roof, clothes. Said all I had to do in return was fight for him. Become his champion.” A bitter laugh escaped him. “Didn’t realize back then what that really meant.”
Your chest ached as he went on, each word heavier than the last. “I can’t get out now. Every fight, nearly all the money I make goes straight back to him to cover ‘expenses.’ The apartment, the training, the meals. I can’t leave the house without depending on him for something, which only means more debt I have to fight off. It’s a cycle. And he knows it. That’s why he keeps me close.” His voice broke softer at the edges. He stared down at the ground, food forgotten in his hands. “I gave up hope a long time ago. This is just what my life is.”
You swallowed, heart twisting. “But why don’t you go to the police? They’d see this for what it is.”
He snorted, shaking his head. “And tell them what? That I’ve been boxing illegally for years? That I let myself get tied up in this?” He rubbed his face with one hand, weary. “Doesn’t work that way.”
“You didn’t really have a choice,” you said firmly. “You were a kid. You were forced into this.”
At that, he finally looked at you, his dark eyes catching the shimmer of city lights. A muscle in his jaw flexed as he sighed. “I’m not a kid anymore, am I?” His voice was quiet, resigned. “Doesn’t change the fact that I’m still here.”
The river rolled on in silence, the night air heavy around you. And though you didn’t know how yet, you felt the weight of his words settle in your chest — a promise to yourself that if he had given up hope, you wouldn’t.
-
The days after your night by the river weighed differently. You carried his words with you, the way his voice had sounded when he said he’d given up hope. It haunted you more than you expected.
And yet, he kept coming back. Another fight, another round of bruises. By now, you’d grown used to seeing his shadow darken your backroom doorway, shoulders hunched, expression guarded. Tonight, though, he was worse off than usual. His lip split, his ribs badly bruised, one eye nearly swollen shut. You clicked your tongue softly, motioning him into the chair. “You let him hit you too many times.”
His voice came out dry. “Guess I’m not invincible.”
“You never were,” you countered, tugging on gloves. “You’re human. And that means you’re allowed to break sometimes.”
For a while, there was only the sound of cotton against skin, antiseptic stinging wounds, his occasional hiss of pain. But when you wrapped his ribs, your hands brushing too close to his bare skin, he spoke again, quiet, like he hadn’t meant to. “You asked me why I don’t leave.” His eyes stayed fixed on the wall, jaw tight. “It’s not just the money. It’s him. My trainer. He took me in when no one else would. Sometimes I hate him. But I also,” His throat bobbed. “I don’t know who I am without this.”
You froze for half a second, tape half-wrapped around his torso, before finishing the bandage. “You’re Seo Changbin,” you said firmly. “Not just a fighter. Not just a champion in some ring. You could be anything, if you weren’t shackled to him.”
He gave a humorless laugh, low and sharp. “Anything? Like what? I’ve spent half my life throwing punches. That’s all I know.”
“You know more than you think,” you said, tilting your head at him. “You think you’re trapped, but I see someone who hasn’t even tried to imagine something else. You say you gave up hope, but that doesn’t mean it’s gone.”
His eyes finally met yours, and for a heartbeat, the hardness cracked. He looked young. Tired. Vulnerable in a way he’d never let the crowd, or even his trainer, see. “You make it sound so simple,” he muttered.
“Simple doesn’t mean easy,” you replied softly. “But nothing changes unless you believe it can.” He looked away again, lips pressing together, and you let the silence stretch, knowing he needed it. When you finally stepped back, gloves stripped off, you gave him a small smile. “All done. Try not to let anyone punch you in the face next time.”
A huff of air left him, not quite a laugh, but close. He stood, moving carefully, his hand brushing the bandage at his ribs. “Thank you,” he said again, the same quiet gratitude you’d first heard from him weeks ago. But this time, there was something heavier underneath it. Something like a plea. And as you watched him disappear back into the shadows of the underground, you knew you couldn’t just let him give up on himself.
-
It wasn’t after a fight this time. You were closing up your clinic for the night, slipping your coat on, when a sharp knock rattled the back door. You opened it expecting one of the usual fighters, but instead, Changbin stood there, swaying on his feet. His face was pale, lips pressed thin, and when he stepped inside the light you saw blood soaking through his shirt, fresh and ugly. “Changbin—”
“Not a fight,” he cut in quickly, almost defensive. His voice was rough, strained. “Not the ring.”
That almost made it worse. You pulled him toward the chair, fumbling for gloves and gauze, heart pounding. “What happened?”
He didn’t answer right away, only winced as you pressed into his side, revealing a jagged cut across his ribs. It was messy, not from a fist but something sharper. “Ran into some guys I shouldn’t have,” he muttered finally, eyes fixed on the floor. “They knew who I was. Knew I couldn’t hit back unless I wanted trouble. So I took it.”
Your jaw tightened. “They attacked you because of the ring?” His silence was answer enough. You stitched him up quickly, your hands steady even though your chest burned with frustration. He didn’t flinch much, just sat there like he was used to enduring worse. When you finally finished, you sighed, stepping back. “This can’t keep happening, Changbin. If your trainer’s putting you at risk outside the ring now—”
His eyes lifted, dark and heavy. “You don’t get it. He owns me. If I don’t fight, I don’t eat. If I push back, I don’t have a roof over my head. And if I lose, I don’t know what he’ll do.”
The words hit harder than any bruise. But before you could answer, the sound of heavy footsteps echoed down the hall. The backroom door slammed open, and his trainer filled the frame — broad, grinning, reeking of liquor and smoke. “There you are,” the man barked. His eyes flicked from you to Changbin. “Didn’t tell me you had your little doctor on retainer.” Changbin stiffened, every muscle in his body taut. The trainer stepped closer, voice booming. “He’s good enough to fight again. Wrap him up, get him in the ring tomorrow. Big bets lined up. Don’t let me down, boy.”
Your stomach twisted. “He’s not ready,” you said before you could stop yourself. “If he goes in with ribs like this, he’ll collapse.”
The trainer’s gaze snapped to you, sharp and mocking. “Didn’t ask for your opinion, sweetheart. He fights when I say he fights. That’s the deal.” He clapped a heavy hand onto Changbin’s shoulder, squeezing hard enough to make him wince. “Be ready tomorrow night. Or you’ll regret it.” And then he was gone, leaving the room colder than before.
Changbin sat there, silent, staring at the floor as if it might swallow him whole. His fists were clenched so tight his knuckles turned white. You knelt in front of him, voice steady but low. “You can’t keep letting him do this to you.”
His eyes lifted, and for a second, you saw it — not just pain, but a spark of something else. Anger, desperation, but also fear. “I don’t know how to stop him,” he whispered.
-
You barely slept that night. The trainer’s words replayed over and over, mixing with the image of Changbin sitting there bloodied and silent, too beaten down to even argue. By the time the sun rose, you’d made up your mind: if he wouldn’t fight for himself, then you’d fight for him.
Between your shifts at the hospital, you dug through everything you could find. Laws about illegal rings. Cases of forced labor. Stories of fighters who’d managed to escape. Every thread was thin, tangled in bureaucracy, but the more you read, the clearer it became — what his trainer was doing wasn’t just cruel. It was criminal.
Still, theory and practice were two very different things. And you knew Changbin. He wouldn’t just walk into a police station. Not while the weight of his past and the fear of consequences kept him chained. So when he showed up after another grueling night, bruised, but alive, you decided to try something different. You stitched him in silence at first, his face turned away, jaw locked tight. When you finished, you didn’t step back. Instead, you leaned against the table, arms crossed, watching him. “You don’t have to keep living like this,” you said quietly.
His eyes flicked to yours, wary. “You think I haven’t tried to imagine something else?”
“Have you?” you pressed. “Really? Because every time I ask, you shut down. You don’t tell me what you want. You just accept what he gives you. A roof over your head, food, and chains.”
His fists clenched in his lap. “What choice do I have?”
“You could leave.” The words came out firm, sharper than you expected. “Walk away. You were forced into this as a kid, Changbin. That doesn’t mean you have to die here.”
He laughed short and bitter, almost broken. “Walk away? And go where? With what money? What skills? What if he finds me?”
You softened your voice, leaning closer. “Then we figure it out. Together. I’m not saying it’s easy. I’m saying it’s possible. And you deserve more than this.”
For the first time, his mask cracked. His eyes shone, not just with pain, but with a longing he seemed terrified to admit. He looked down, swallowing hard, voice low. “I used to think I’d be somebody when I was younger. Before all this. Music, maybe. Writing. I didn’t care as long as it was mine.” He shook his head, bitterness returning. “But that was another life. He’s taken too much for me to go back.”
“Then don’t go back,” you whispered. “Go forward. Start new. Even if it’s small. Even if it’s hard.”
The silence stretched, heavy between you. Finally, he exhaled, a sound halfway between defeat and release. “You make it sound like freedom’s just sitting out there, waiting for me.”
“Maybe it is,” you said, holding his gaze. “But you won’t know until you try.”
He stared at you for a long time, his expression shifting. Then, almost too quiet to hear, he admitted: “I don’t think I can do it alone.”
Your heart clenched, but you didn’t look away. “Good thing you’re not.”
-
It was late, the air heavy with the damp chill of approaching winter. Changbin sat quietly on the chair in your backroom, ribs wrapped, knuckles raw from another fight. You’d grown used to the silence between you two, the way he spoke only when it mattered. This time, you broke it. “How much do you owe him?” you asked softly, wiping your hands on a towel.
His head lifted slightly, eyes narrowing like you’d just cracked open a door he kept locked tight. After a pause, he muttered the number. It was higher than you expected, enough to crush someone twice over. You only nodded, keeping your expression gentle. “Alright.”
His brow furrowed. “That’s it?”
“That’s it.” You gave him a faint smile. “I just wanted to know.”
But after that, he grew quieter around you. Hesitant. It was as if telling you the number had pressed too close to the heart of his cage, and he retreated back into himself. A distance grew, and though he still came after fights, he barely met your eyes. You didn’t push.
Not until a month later. When he showed up again, slumped in the doorway after another brutal match, you guided him inside as usual. But instead of reaching for your medical bag, you pulled an envelope from the drawer and pressed it into his hand.
He blinked down at it, confused, then slid a thumb beneath the flap. The sight of the bills inside made his jaw fall slack. “…What is this?”
“It’s yours,” you said simply. “No strings attached.”
He stared at you like you’d just handed him the moon. “I can’t take this.”
“You can,” you insisted, voice steady. “This is my good deed. For not being able to save my friend, I’ll save you instead.”
His throat worked, words caught there. Then his gaze flicked past you and froze. His trainer was outside, waiting in the hallway, eyes narrowing as he spotted the envelope in Changbin’s hands. Before you could react, Changbin was on his feet, striding out the door. He shoved the envelope at the older man, voice firm though it shook faintly. “Take it. I’m done. I quit.”
For a heartbeat, silence. The trainer looked down at the money, then back up at you, realization dawning like fire. His face twisted, fury boiling over as he rushed toward you, spitting venom. “You think you can buy him out from under me? You think you can take my champion? You’ll regret this!”
You stumbled back, heart hammering, but before he could reach you, Changbin stepped in front, arm braced out like a shield. His glare was cold, his body blocking the man’s path. “She’s not your problem,” he growled. “I said I’m done.”
The trainer’s curses echoed down the hall, but Changbin didn’t move until the man stormed off, swearing under his breath. Only then did he turn to you, shoulders tight, eyes wide with something raw.
That night, you took him home. Your apartment was small, cluttered with books and blankets, but as he stood awkwardly in your doorway, you saw the way his frame sagged, exhaustion finally winning. He wasn’t a fighter here. He was just Changbin — tired, hurt, and free for the first time in years. “Stay as long as you need,” you said quietly, ushering him in.
For the first time since you’d met him, he smiled without hesitation. “Thank you,” he whispered.
And when you closed the door behind him, you knew this was only the beginning...
PART TWO
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