TOTAL INSECURITY .
⌗ pairing: {established relationship} katsuki bakugou x jealous! reader
⌗ trigger warnings: jealousy, insecurity, self-doubt, emotional distress, anxiety, miscommunication, crying, negative self-talk.
⌗ anon request: hello! I was wondering if you could make a story where y/n is getting jealous over katsuki getting close to another girl classmate? like basically him and another girl in class 1-a start training and hangout a bit and reader starts getting a bit jealous and insecure, basically a comfort fic. i’d really appreciate it cause i’m kind of in a mood today 🥹
⌗ a/n: thx for requesting this!! uh, i decided to use a random Japanese generator name thingy because i didn’t want to use any of the actual mha girls. and yes, I am doing requests. I JUST CAN’T FIND PHOTOS.
the first time you noticed her, she was standing at the front of class 1-a with that nervous smile transfer students always wore. emiko tanaka—her quirk was something called "energy sync" that let her match and amplify others' abilities temporarily. aizawa had explained it in his usual monotone, but you'd been more focused on the way katsuki's eyes had lingered on her demonstration.
"interesting," he'd muttered, and something cold had settled in your stomach.
you'd been dating katsuki for six months now. six months of his rare soft smiles, of him walking you to class with his hand in yours, of quiet moments where his guard dropped completely. you thought you'd gotten past the worst of your insecurities, but watching emiko successfully sync with his explosions during their first paired training session brought them all rushing back.
"she's really good," kirishima commented, watching as emiko's borrowed explosions created a perfect crater in the training ground. "her control is insane."
"yeah," you managed, throat tight. "really good."
katsuki was grinning—actually grinning—as he helped emiko up from where she'd been knocked back by the recoil. when was the last time he'd smiled like that during training? when was the last time he'd looked at you like that? you tried to remember, but all you could focus on was the way his hands lingered on her arms as he steadied her, the way she looked up at him with those bright eyes full of admiration.
over the next few weeks, it became routine. emiko would pair with katsuki for combat training, their quirks complementing each other perfectly. she could handle his explosive power better than anyone else in class, and he seemed to thrive on having a partner who could keep up. you watched from the sidelines during training, paired with whoever was left, trying not to notice how natural they looked together.
you told yourself it was just training. professional. but then you started noticing the little things.
the way katsuki would wait for her after class, both of them heading to the gym for extra practice while you walked back to the dorms alone. how he'd explain techniques to her with unusual patience, his voice lacking its typical harsh edge. the inside jokes that developed between them—references to their training sessions that made her laugh and him smirk with satisfaction. how she'd save him a seat at lunch sometimes, or bring him notes from classes he'd missed.
you found yourself studying them during meals, watching how comfortable they'd become with each other. emiko would steal food from his plate without him threatening to explode her face off—something that had taken you months to achieve. she'd tease him about his study habits, and he'd actually laugh instead of shouting. worse, she understood his ambitions in a way that felt similar to you, nodding along when he talked about being the number one hero, asking questions that showed she actually listened.
"you're being ridiculous," you whispered to yourself one evening, watching through the gym windows as they worked through a complex combination attack. emiko was practicing syncing with his explosions while moving, and every time she succeeded, katsuki's face would light up with genuine pride. but when she stumbled and katsuki caught her, steadying her with hands on her waist, both of them laughing breathlessly from the exertion, you couldn't stop the tears that blurred your vision.
you turned away before either of them could see you, but not before you heard emiko say, "thanks, katsuki. you're an amazing teacher." the warmth in her voice made your chest ache.
the breaking point came during a weekend study session. you'd been looking forward to spending time with katsuki, had even picked up his favorite snacks from the convenience store. but he'd gotten a text from emiko about needing help with a hero law assignment.
"rain check?" he'd asked, already reaching for his jacket. "she's struggling with the case studies, and you know how brutal those are."
you'd nodded, forced a smile, told him it was fine. but as you watched him leave, something inside you cracked. he used to help you with hero law. he used to be the one you could count on for study sessions and quiet conversations about your dreams. you remembered sitting in his room for hours, him patiently explaining legal precedents while you struggled to understand the complex cases.
now he was rushing off to help someone else, and you were left wondering if you were being replaced. the snacks sat unopened on your desk, mocking you.
the next few days passed in a blur of forced normalcy. you smiled when katsuki kissed you good morning, laughed at his jokes, pretended not to notice when he and emiko would disappear for their training sessions. but the doubt was eating at you, whispering cruel things in the quiet moments.
she's stronger than you. more compatible with his quirk. she doesn't flinch when he shouts, doesn't need the gentle handling you sometimes require. she's everything you're not.
you started avoiding the gym, finding excuses to skip group training sessions. when katsuki asked why, you'd claim you were tired or had homework. the lies tasted bitter on your tongue, but you couldn't bear to watch them together anymore, couldn't stand seeing how effortlessly she fit into the space you'd thought was yours.
mina noticed first, cornering you after class one day. "hey, what's going on? you've been weird lately."
"nothing," you'd deflected, but she saw right through you.
"it's about bakugou and the new girl, isn't it?" she'd said gently, and your face must have given you away because she sighed. "oh, honey."
"it's stupid," you'd whispered, but mina shook her head.
"feelings aren't stupid. but you should talk to him instead of torturing yourself like this."
but how could you? how could you tell the person you loved that you were terrified of losing him? that every interaction he had with emiko felt like a knife in your chest?
you were so lost in your thoughts that you didn't notice katsuki approaching until he dropped into the seat beside you at lunch.
"you're being weird," he said without preamble, red eyes studying your face. "what's wrong?"
"nothing," you replied automatically, stabbing at your rice with more force than necessary. across the cafeteria, you could see emiko sitting with some of the other girls, occasionally glancing over at your table.
"bullshit." his voice was low, meant only for you. "you've been avoiding me for three days. did i do something?"
the concern in his tone almost broke you. this was katsuki—your katsuki—who noticed when you were upset, who cared enough to ask. but then you saw emiko approaching from across the cafeteria, and the doubt came rushing back.
"i'm fine," you insisted, standing abruptly. "i just... i need some air."
you felt his eyes on you as you left, but you didn't turn back. you also didn't see the confused look he exchanged with emiko when she asked if you were okay.
that evening, you were sitting on your bed, staring at your homework without really seeing it, when someone knocked on your door. you knew that knock—sharp, impatient, but not aggressive. katsuki.
"we need to talk," he said when you opened the door, and his expression was serious enough that you stepped aside to let him in.
he sat on your desk chair, turning it to face you as you perched on the edge of your bed. for a moment, neither of you spoke. you could hear the sounds of your classmates in the hallway, muffled conversations and laughter that felt worlds away from the tension in your room.
"are you breaking up with me?"
the question hit you like a physical blow. "what? no! why would you—"
"because you've been acting like you can't stand to be around me," he interrupted, running a hand through his hair. "and i can't figure out what i did wrong."
the raw vulnerability in his voice made your chest ache. this was what your insecurity had done—made the person you loved most think he was losing you.
"you didn't do anything wrong," you said quietly. "i just... i've been stupid."
"about what?"
you took a shaky breath, fingers twisting in your lap. "about you and emiko."
katsuki's eyebrows shot up. "me and—what the hell are you talking about?"
"you've been spending so much time with her," you continued, the words tumbling out now that you'd started. "training together, studying together, and she's so good with your quirk, and you smile at her in ways you haven't smiled at me in weeks, and i just—" your voice cracked. "i started thinking maybe you realized you'd be better off with someone who could actually keep up with you."
the silence that followed was deafening. you couldn't bring yourself to look at him, couldn't bear to see confirmation of your fears in his expression.
then you felt the bed dip as he sat beside you, his hand covering yours.
"look at me," he said softly, and when you reluctantly met his eyes, they were intense but gentle. "you really think i'd rather be with her?"
"i don't know," you whispered. "maybe? she's stronger than me, her quirk works better with yours—"
"stop." his hands came up to cup your face, thumbs brushing away tears you hadn't realized were falling. "just stop."
he leaned forward, pressing his forehead against yours. "you wanna know why i've been training with her so much? because aizawa paired us up for the upcoming exercise, and i didn't want to look like an idiot in front of the whole class. you wanna know why i help her with homework? because she asked, and i'm not a complete asshole, despite what everyone thinks."
his thumbs traced across your cheekbones. "but you wanna know what i think about when i'm with her? i think about how she's not you. how her laugh doesn't make my chest feel warm, how she doesn't know that i like my coffee with too much sugar, how she's never seen me have a nightmare and stayed up all night to make sure i was okay."
"katsuki—"
"i'm not done." his voice was firmer now, more like the katsuki you knew. "she's a good training partner. hell, she's a good person. but she's not the person i want to come home to. she's not the person i think about when i'm falling asleep, or the person i want to tell when something good happens."
he pulled back slightly, forcing you to meet his eyes. "she's not you, and she never could be. you think i care about quirk compatibility? about who's stronger? i fell in love with you because you're you—because you see good in people, because you believe in me even when i don't believe in myself, because you make me want to be better than i am."
"but you seem so happy when you're with her," you protested weakly.
"i'm happy when i'm getting stronger. when i'm working toward being the best hero i can be. but you know what makes me happiest?" he leaned in, pressing a soft kiss to your forehead. "coming back to you afterward. telling you about my day, hearing about yours, just... being with you."
the last of your defenses crumbled. "i'm sorry," you breathed. "i'm so sorry, i just—"
"got scared," he finished, pulling you into his arms. "i get it. but next time you're feeling like this, talk to me, okay? don't just disappear on me. i can't fix a problem if i don't know it exists."
you nodded against his chest, breathing in the familiar scent of his cologne mixed with something uniquely him. "i love you," you murmured.
"love you too," he replied, pressing a kiss to the top of your head. "more than you know."
you stayed like that for a long moment, wrapped in each other's arms, before katsuki spoke again.
"for the record, though, your quirk works perfectly with mine too. remember last month when we took down that simulation villain together? that was all us, no borrowed power needed."
you pulled back to look at him, finding that familiar smirk on his face. "you're never going to let me live this down, are you?"
"nope," he said, popping the 'p'. "my partner got jealous over a training buddy. it's pretty cute, actually."
"shut up," you laughed, pushing at his shoulder, but he caught your hand and brought it to his lips.
"make me," he challenged, eyes twinkling with mischief.
so you did, leaning in to kiss him properly, pouring all your love and relief and apologies into the gesture. when you finally broke apart, breathless and smiling, you felt like yourself again.
"so," you said, settling back against his side, "tell me about this training exercise you're so worried about."
and as he launched into an explanation of the complex scenario aizawa had planned, complete with dramatic gestures and colorful commentary about your classmates' weaknesses, you realized something important: this was what you'd been missing. not the explosive training sessions or the patient tutoring, but this—the quiet intimacy of sharing daily life with someone who chose you, again and again.
emiko was a good training partner. but you were katsuki's everything, and he was yours.
that was more than enough.
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