"Your New Favorite Hero" | Bakugo Katsuki x Female Reader
Pairing: Katsuki Bakugo x Female reader
Summary: Haru Bakugo, a energetic six-year-old, is picked up from school by his grandma Mitsuki, who reveals that his parents are at the hospital because his mama just gave birth to a baby sister. Excited, Haru rushes to the hospital where he meets his new sibling for the first time.
Content: fluff, family fluff, domestic fluff, toddler pov, big brother feels, hospital birth (not described), soft bakugo, protective husband, proud parents, wholesome family moment, mild language, pure tooth-rotting fluff, no angst
a/n: this was a draft was too cute not to be posted so here yall go<3
The afternoon sun filtered through the windows of Aldera Elementary School’s first-grade classroom, casting warm golden patches across the colorful rug where little Haru Bakugo sat cross-legged with his classmates. At six years old, Haru was a miniature storm of energy, spiky ash-blond hair that refused to be tamed no matter how much you brushed it that morning, sharp crimson eyes exactly like his father’s, and a grin that could light up the whole block. His uniform was already a little rumpled from recess, the sleeves rolled up because “heroes don’t need long sleeves, Mama,” he’d declared while you helped him dress.
Today had been a good day. They’d practiced basic quirk control in the school’s safe training yard, Haru’s tiny palms sparking with miniature explosions that popped like fireworks when he got excited. The teacher, Miss Aizawa (no relation to the pro hero, but she always laughed when kids asked), had praised him for keeping them controlled. “You’re getting so strong, Haru-kun,” she’d said, ruffling his hair. He’d puffed out his chest, already imagining telling Papa all about it when he got picked up.
But when the final bell rang and the other kids bolted for the door, Miss Aizawa called his name softly. “Haru-kun, your grandma is picking you up today instead of Mama or Papa. She’ll be here in just a minute. Pack your bag nicely, okay?”
Haru blinked, tilting his head. Grandma? That was weird. Mama always picked him up on Tuesdays because Papa had patrol until late. He shrugged it off, stuffing his hero-themed notebook into his backpack with the little All Might keychain you’d bought him last month. “Okay, sensei!” He waved at his friends and skipped toward the pickup line outside, sneakers squeaking on the linoleum.
Mitsuki Bakugo was already waiting by the curb in her sleek black car, leaning against the door with her arms crossed and that familiar loud, confident smirk on her face. Her ash-blond hair was pulled back in a stylish ponytail, and she wore a bright red blouse that matched the fiery personality she’d passed down to both her son and grandson. The second she spotted Haru, her whole face lit up like a firework.
“There’s my little explosion boy!” she boomed, scooping him up into a hug that smelled like expensive perfume and the faint trace of nitroglycerin from the hand lotion she still used out of habit. Haru giggled as she spun him once before setting him in the booster seat in the back. “Buckle up, kiddo. We’ve got places to be.”
Haru clicked the belt into place, kicking his legs happily. “Hi, Grandma! Where’s Mama? And Papa? Did Papa catch a big villain today? I made the biggest boom at school, bigger than last week!”
Mitsuki slid into the driver’s seat, adjusting the rearview mirror so she could see his excited face. The car smelled like fresh leather and the strawberry candy she kept in the glovebox just for him. She started the engine, pulling away from the school with a gentle rumble. For a long moment, she didn’t answer, just smiled that soft, knowing smile she saved for family moments like this. Her hands gripped the wheel a little tighter, but her voice stayed warm and steady.
“Haru, sweetie… Mama and Papa aren’t home right now,” she said, glancing back at him in the mirror. Her tone was gentle, the kind she used when she was about to drop something big. “They’re at the hospital.”
Haru’s little eyebrows furrowed. He stopped kicking his legs. “The hospital? Is Mama sick? Did she get hurt fighting a bad guy with Papa?” His voice wobbled just a tiny bit six-year-olds had big imaginations, and in a world full of heroes, hospitals meant scary things sometimes. But Mitsuki’s laugh was bright and reassuring, cutting through the worry like sunshine.
“Oh, no, no, nothing like that, my brave little man. They’re there because they have a surprise for you. A really, really good one.” She reached back with one hand to pat his knee at a red light, her rings glinting. “You remember how Mama’s been getting really big in her belly? How she lets you feel the baby kick sometimes?”
Haru nodded slowly, eyes widening. “Yeah… the baby’s been practicing explosions in there. Papa says it’s gonna be strong like me.”
Mitsuki’s grin grew wider, almost mischievous. “Well, the baby decided today was the day to come out and meet everyone. Your mama went into labor this morning, real quick and strong, just like her. Papa rushed her to the hospital, and now… you’ve got a brand-new little sister.”
The car was quiet for a second except for the soft hum of the engine and the distant city sounds outside. Haru’s mouth fell open in a perfect little O. A sister. Not a toy, not a new All Might poster, not even a pet like he’d begged for last month. A real sister. His brain spun with the news, images of tiny hands and maybe her having explosions too, or maybe your soft smile and gentle quirk that always made flowers bloom when you were happy.
“Really? A sister?” he whispered, then louder, bouncing in his seat as much as the belt would let him. “Like… I’m a big brother now? Can I teach her how to make booms? Will she like hero shows? Grandma, drive faster!”
Mitsuki laughed so hard the car swerved a tiny bit before she corrected it. “Whoa there, mini-Dynamight! Hospitals have rules, and your mama needs rest. But yes, you’re a big brother now. And she’s perfect, tiny little thing with your papa’s hair already, from what he texted me. We’ll be there in ten minutes. Just remember: be gentle when you meet her, okay? Babies are squishy and new.”
The rest of the drive was filled with Haru’s rapid-fire questions. “What’s her name? Does she have my eyes? Can I hold her? Papa’s gonna be all soft like when he thinks no one’s looking, right?” Mitsuki answered every one with patience and laughter, telling him stories about when Katsuki was a baby.
By the time they pulled into the hospital parking lot, Haru was practically vibrating. The building loomed tall and clean under the late afternoon sky, cherry blossoms from the trees outside drifting like soft pink snow. Mitsuki parked, helped him out, and took his hand as they walked through the sliding doors. The lobby smelled like antiseptic and fresh flowers from the gift shop. A nurse at the desk smiled when Mitsuki gave your name, and soon they were riding the elevator up to the maternity ward, Haru clutching his backpack like it was a shield.
Room 412 was quiet except for the soft beep of monitors and the tiniest, most delicate cry Haru had ever heard. Mitsuki knocked once, then pushed the door open gently.
You looked exhausted but radiant, propped up in the hospital bed with pillows fluffed behind you, wearing the soft blue gown the hospital provided. Your hair was a little messy from labor, but your eye—those eyes Haru loved because they were yours, lit up the second you saw him. Sweat still glistened on your forehead, but your smile was the biggest, warmest one he’d ever seen.
Katsuki Bakugo sat right beside you in a chair pulled so close their knees touched, one arm around your shoulders like he’d never let go. His hero costume was rumpled from the rush, he’d clearly changed out of it in a hurry and thrown on a black hoodie and sweats, but his crimson eyes were softer than Haru had ever seen them outside the house. In his free arm, cradled against his broad chest like the most precious explosive in the world, was a tiny bundle wrapped in a pink blanket.
“Haru,” you whispered, voice hoarse but full of love. You held out one hand, and he ran to you without hesitation, climbing carefully onto the edge of the bed so he could hug you without squishing anything. “My big boy. Come meet your sister.”
Katsuki’s voice was gruff but thick with emotion he’d never admit to in public. “Tch. Don’t crowd your mom, brat. She did all the hard work today.” But the way he said it was gentle, his free hand coming up to ruffle Haru’s hair exactly the way he always did at home. Up close, Haru could see the new baby clearly: a tiny face with the faintest dusting of ash-blond fluff on her head, little fists curled up, and the softest whimper as she stirred.
Mitsuki hovered by the door, wiping her eyes with the back of her hand. “She’s gorgeous, you two. Looks just like you did, Katsuki, except hopefully with better manners.”
Haru stared, mesmerized. “She’s so small,” he breathed. “Hi, little sister… I’m Haru. I’m gonna be the best big brother ever. I’ll show you how to explode stuff when you’re bigger, and we can watch hero cartoons together, and, and Papa will make you spicy curry like he does for me when you’re old enough, okay?”
The baby let out a tiny coo, almost like she understood. You laughed softly, the sound tired but overflowing with joy, and pulled Haru closer so he could rest his head against your shoulder. Katsuki shifted the bundle carefully, lowering her just enough for Haru to see her face better. “Her name’s Hikari,” Katsuki said, voice low and proud. “Means light. Because that’s what she is, another damn light in our family. You did good, kid. Real good.”
Hikari. Haru repeated it in his head like a hero’s name. He reached out one careful finger and touched her tiny hand. Her fingers wrapped around it instinctively, and Haru’s eyes went wide. “She’s holding me! Mama, look!”
You kissed the top of his head, breathing in the familiar scent of his shampoo mixed with playground dirt. “She already loves you. Just like we do. Today was scary for a minute, but you being here makes it perfect.”
Katsuki leaned in, pressing a rare, lingering kiss to your temple right in front of everyone, grandma included. “You were incredible, dumbass,” he muttered against your skin, the nickname wrapped in so much affection it might as well have been “my everything.” “Pushing out another explosion brat like it was nothing." His hand found yours, calloused fingers intertwining with the gentleness only you and the kids ever got from him.
Mitsuki couldn’t hold back anymore. She bustled over, pulling out her phone to snap a million pictures. “Smile, you sappy bunch! This is going in the family album. Haru, get in there, big brother pose!” Haru puffed up, making a tiny explosion spark in his free hand (just a safe pop, the way the school taught). The flash caught all of you: you cradling Haru, Katsuki holding Hikari like she was made of glass, Mitsuki beaming in the background.
For the next hour, the room filled with quiet fluff. Haru told you every detail of his school day in a rush, voice never dropping below excited. Katsuki grumbled about the hospital food but fed you bites of the bento Mitsuki had brought, making sure you ate every grain of rice. “Gotta keep your strength up, idiot. Can’t have you passing out before we get home.” You teased him right back, calling him “softie” under your breath, and he only blushed and told you to shut up while kissing your knuckles.
Hikari fussed once, and Katsuki was on his feet instantly, rocking her with that same rhythmic sway he used when Haru was a newborn. “Yeah, yeah, I know. World’s loud. But you got us now, kid.” Haru watched, mesmerized, then climbed into your lap again, resting his head against your chest the way he did when he was smaller. “Mama… can we take her home tomorrow? I wanna show her my room and my All Might posters.”
“Soon, baby,” you murmured, stroking his hair. “The doctors want to make sure she’s super strong first. But we’ll be home before you know it. And Papa’s taking time off patrol so he can help with everything.”
Katsuki snorted from across the room, but his eyes were warm. “Damn right. No one’s blowing up my family time. Not even villains.”
As the sun dipped lower outside the window, painting the room in soft oranges and pinks, the four of you, five, now settled into a peaceful hush. Mitsuki eventually slipped out to grab coffee and give you space, promising to return with more pictures for the grandparents’ group chat. Haru’s eyelids grew heavy against your shoulder, the long day catching up to him, but he fought sleep just to keep staring at Hikari’s tiny face.
You caught Katsuki’s eye over the baby’s head. He looked at you the way he had since the day you met, like you were the only person in the world who could make the great Dynamight melt. “Love you,” he mouthed, no words needed because you already knew. You mouthed it back, heart so full it felt like it might burst the same way his quirk did.
Haru sighed happily in his half-sleep. “Best… surprise… ever.”
And in that quiet hospital room, with the beeps and the soft baby breaths and the love that filled every corner, it really was. Your little family, loud, explosive, and perfectly yours—had just grown by one more perfect light. Tomorrow you’d go home, start new routines, navigate sleepless nights and sibling giggles and Katsuki’s terrible attempts at singing lullabies.
But right now, in this moment, everything was exactly as it should be: warm, safe, and overflowing with the kind of fluffy, unbreakable joy only your Bakugo boys (and now your Bakugo girl) could bring.
Credit for divider: @kodaswrld @mikeykuns @cursed-carmine
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