Izuku jingled his keys into the lock, talking about homework he had to do with Iida and Ochako as the three stepped over the door frame into the Midoriya household for the first time since they’d become friends.
Izuku had always rejected the idea of going to his house with his friends. The three would usually study at Iida’s because his family could afford having guests round. The two friends didn’t question why the boy was so adamant to go to Iida’s all of the time but respected his decision.
Until that day, when Izuku had finally asked the two if they’d like to come to his house to study, they obviously agreed.
So there they stood in the hallway of the Midoriya home.
Izuku chucked his All Might themed keys into a bowl on the hallway table and took his shoes off, slipping on a pair of slippers and went to get his guests a pair.
“Welcome.” He said confidently, a shaky smile on his face as he placed two pairs of slippers on the floor for his friends to wear.
Ochako watched an older woman come from the other end of the hallway; she had a nervous smile on her face.
“Ah, you must be Izuku’s friends!” The woman said, bowing. “My name is Inko; it’s nice to finally meet you both.”
Iida and Ochako repeated back what the woman said and her grin widened.
A shock of blonde went past their sight and Iida let out a manly yelp as Miroriya was tackled into a hug. Izuku was kneeling on the floor, obviously expecting the youngster to give him a welcoming hug.
The two best friends stared, Ochako nervously laughed; he must’ve meant the older woman…
“Hey buddy. Did you have a good day with Nan?” Izuku said, detaching the blonde energy ball from his body.
Ochako and Iida stood, mouths hung open.
“Yeah it was real fun! We made cookies, I made you one. Come, come look!” The boy said; already grabbing Izuku’s uniformed sleeve and dragging him to the kitchen where a counter full of warm cookies lay…
“Ah, Kinumi say hello to Iida-san and Ochako-san.” Izuku said, stopping the boy from giving him his own personally decorated cookie. “Politely…” He added as he saw the pout forming on the young boys face.
The blonde, looked up with a sharp and very familiar smile and held up a confident hand to wave up at the guests. “Hi Iida-san, Ochako-san!” Izuku smiled, praised him for being polite and took one of the cookies from the plate, not expecting it to be so hot.
“No-no mamma. This one is yours. I painted it to look like your hero costume. See it’s got green and black on it.” The blonde boy around five years old said, snatching the cookie in Izuku’s hand and placing another, unrecognisable, cookie in his hands.
Iida scrutinised it, looked at the blob of green in his friends hand from behind his shoulder and scoffed. Ochako only stared at the spiky locks of the child who was dancing around Izuku as he bit into the badly decorated cookie.
“It’s good Kinumi and you did a good job with my hero costume design.” Izuku said, appeasing the child’s dancing so he could gloat at the praise.
Iida scoffed, the design didn’t look anything like Midoriya’s costume…
What Iida did not expect was for a cookie to be passed to him from the blonde boy. His critical red eyes bore into the seniors. “Mumma told me Ing- Ingenum was coming here so I made you one too; can’t you see the silver and blue?” The sweet gesture from the child shot an arrow into Iida’s practical heart and he took the cookie. He examined the glub of white (not silver…) icing on top of the cookie and smiled.
A practically red (not pink) iced cookie was placed into Ochako’s petite hands. “Ah, who’s this?” She asked, seeing the excited expression on the boy’s face disappear. “Are you blind? It’s you.” The kid said with a scowl on his face.
“Kinumi…” Izuku said; tone of voice low in warning. “That’s no way to speak to a guest…” Izuku went to Ochako’s side. The more the blonde kid scowled the more she grew fearful, he looked awfully familiar…
The freckles dusting his cheeks were similar to Izuku’s own but the eyes and hair were completely different. The kid was blonde and had amber eyes for Christ sake…
“Izuku wha- mumma?“ She began, giving her friend an odd look.
Izuku swallowed the remainder of his cookie dryly. “Well, that was kind of the reason I didn’t want anyone coming here.”
Awkward silence filled the kitchen apart from the five year old who was trying to bash into Izuku legs, strangling his calves with his legs.
“You probably have a lot of questions…” The freckled boy said, scratching at his cheek in nervousness.
“We’ve been friends for almost two years, how long have you hidden this-“Ochako whispered in a less than friendly tone, pointing at the kid when she said ‘this’ causing the boy to growl at her and try to slap her hand away.
“Say that to my face!” He said, finally catching her hand and biting her. Izuku separated them with a frown.
“He looks like Bakugou…” Iida filled, earning every one’s eyes. “-just an observation.” He added quickly.
Izuku snatched the boy off of his friends hand and sighed, placing the kid on the floor and warning him if he did anything mean again he’d be put in time out which earned him a groan and pout.
He silently set up the kettle on the heater and made his friends tea. Inko had disappeared somewhere in the dining room so she left them to chat in the living room.
The two UA students sat stiffly on the comfy sofa and watched the five year old climb onto Izuku’s knees. He placed his hands around the boy’s neck and snuggled into his shoulder.
“What’s going on Deku-kun?” Ochako started when she saw the boys breathe evening out as he slept.
“Kinumi was born five years ago on January 8th… I was in middle school and had to take time off to study at home whilst carrying.” Izuku answered, changing Kinumi’s position so he was more comfortable.
“Carrying?” Iida’s repeated.
“I didn’t- we- I thought he loved me.” He said, a pained expression crossed his face and he scrunched his eyebrows together, clutching Kinumi tighter waking him up.
“Middle school? ‘He’?” Iida calculated.
“Bakugou…” Ochako finished.
Izuku nodded silently, forcing a smile at his son.
“I don’t think he knows. He was only told I took time off because of stress, they didn’t give him a reason. He came round and demanded to see me but mum didn’t let him in. She wanted to kill him after I told her what happened.”
“And what happened?” Ochako said, earning an elbow from Iida.
“I don’t want to talk about it with Kinumi here. He doesn’t know who his father is and for good reason. He’s becoming more like Kacchan day by day as you saw…”
“He’s as vicious as Bakugou, that’s for certain.” Ochako said, shaking her bitten hand.
“Bakugou?” Surprised eyes locked onto the child who spoke. “Who’s this Bakugou, did he hurt mumma?”
“Ah, Bakugou is only a classmate of ours. He’s like you in a lot of ways.” Izuku answered, avoiding the obvious fact he was keeping secrets from his son.
“He sounds like an ass. I love you mumma.” The child said, cupping Izuku’s face with sweaty hands.
The two friends, new to the family of Midoriya’s/ Bakugou’s?
Found that they liked the kid.
Months passed. Ochako and Iida visited more often and Kinumi opened up to them. After one of the attacks on their school, apartment buildings were built. The UA students were moved into them permanently and Izuku worried for Kinumi, who he couldn’t see as much with all of his exams coming up.
The times Kinumi would visit would be in secret and he liked to imagine he was a spy sneaking past the teachers under his nan’s coat.
That was until one day, he got lost…
His Nan had scolded him for moving when she was walking through the dorms, he got upset and he sprinted away from her, running down the UA dorm corridors. He heard his Nan shouting after him before she ran in the opposite direction.
He’d been told by his mother not to run around the dorm grounds otherwise he could get lost and lost he was…
Every corridor he went down looked identical to the previous and he found himself going in circles.
He passed a water tank that looked suspiciously like the one he had walked past fifteen minutes ago until he found a room filled with a sofa and a TV!
His eyes lit up at the size of the big screen and he walked towards it in awe.
Footsteps bought him out of his thoughts and he turned to see a guy with spiky red hair walk into the room. He was covered in sweat and had a bandana around his forehead.
He noticed the blonde kid immediately.
“Hey…little guy?” Kirishima said, not sure what to do. He’d never seen anyone’s brother in the dorms before. Though he could admit the boy look similar to Bakugou.
“Did you get hit by a quirk Bakugou?” He smirked. “Man, you were a cute kid!” He said, reaching forward to cradle the boy in his arms, alarming Kinumi of stranger danger, he aimed a kick to the boy’s balls and it hit its mark perfectly. The red head dropped the small child and watched the boy run away.
“Oi Bakugou, wait!” The pained man called after the boy.
“What the fuck are you doing shitty hair?” Said man appeared, shocking Kirishima.
“Wait then who was that?!” He rushed after the child, hot on his tail he hardened all of his body in case another kick was to come.
He grasped the collar of the kid and dragged him back, kicking and screaming in his arms. Bakugou stared at him curiously through a scowl.
“You thought that was me.” The explosive boy said, laughing until he saw the kids face properly.
And it was true; the kid did look like him. Identical hair, eyes and foul scowl.
“Mumma!” The kid cried, eyes shedding tears.
Kirishima grimaced at the kid’s hands on his hardened arm. He could feel them heating up, even stronger than Bakugou’s own explosions.
A series of pops exploded from the kids hand and he screamed in pain, alerting everyone on the ground floor of his presents.
Mina appeared out of the kitchen with Sero and Kaminari, curious and pained expressions on their faces as the kid cried.
Majority of class 3A joined soon after, trying to console the child.
“Mumma!” He continued to cry, repeating it over and over again hoping someone would understand.
Meanwhile on the other side of UA Ochako begrudgingly got up from her afternoon nap and got in the lift, she pressed the button to the kitchen and the doors opened a second later.
The scene of most of her class in the common room was a surprise until she noticed a familiar bundle of blonde; the cries emanating from his mouth were horrible. There was blood dripping from his hands and she noticed the man who Izuku didn’t want to find out was right next to the boy, obviously staring at his face.
The people around the boy questioned why they looked so similar to which Bakugou shouted at them.
“Kinumi!” Ochako said, earning the boys attention.
“Ochako-san!” He said, running up to her. She hugged him closely and bought him towards the kitchen, washing the blood off of his hands. They were burnt. His quirk must’ve manifested from his father… his came late- just like Izuku’s.
The rest of 3A minus Kinumi’s own family was missing as well as Iida. She pulled out her phone and dialled the one who Kinumi was screaming for.
He answered on the second dial and she explained the situation.
The front doors to the dorm slammed open and a very puffed out Izuku came through the common room, he pushed everyone out of the way before he saw his son.
“Mumma!” The blonde said, much to Katsuki’s horror.
The two embraced in front of everyone in class 3A, uncaring of the stares.
“You don’t understand how worried I was! Don’t leave your nan’s side ever again.” Izuku scolded, pinching the child’s ear.
His eyes caught onto his hands and he looked at Bakugou.
“What happened?” He asked Ochako.
“Kirshima found him in the common room.” She filled, making Kirishima gain the eyes of the class.
“Ah, I thought Bakugou got hit by a quirk or something. He kicked me in the balls and then made a run for it. I caught him and he set explosions on me!”
“Explosions…” Izuku sighed, already starting to bandage up his boys hands.
“I didn’t know you had a brother Izuku-“ The dumbass Kaminari said, a smile on his face.
“He called him mumma, you dumb shit.” Katsuki added, scowling.
Izuku bought Kinumi towards the sofas and sat down with him on his lap.
The class followed, surrounding the pair tightly.
“Come on guys, give them space…” Ochako said, earning a glare from everyone.
“How come he looks so much like Bakugou?”
“Where’d he come from?”
“Who is he?”
“Is he yours and Bakugou’s secret love child or something?”
Izuku looked at the every single person who asked a question and deliberately ignored them in order to talk to Kinumi who was still trying to calm down from being in shock for so long.
“Kinumi- you know you said you always wanted a cool quirk right?” Izuku said, earning everyone’s attention with his soft voice. Bakugou’s ears perked up at the double meaning to the question. “You have one now.”
Kinumi whined a loud- “But it’s not like mumma’s!”
Izuku smiled, swallowing dryly and sweating from what he was about to admit. “No, you have gained your fathers quirk.”
Safe to say the class exploded- with even more questions and a few seconds later exploded with the use of Katsuki’s actual quirk.
“What’s the meaning of this Deku?!”
Unbelievably the blonde had managed to control his quirk by avoiding Izuku and the kid- he simply obliterated everything around the two.
“Kacchan.” Izuku warned, green lightning etching along his body, ready for a fight. He curled his arms around Kinumi until he felt the boy fall out of his arms.
Sparks flew from Kinumi’s hands and he made pained noises as each explosion was set off. “Don’t you dare hurt my mumma- I’ll kill you.” A sadistic smile came through the pained expression and Izuku sighed- just like his father…
“You meaning to tell me this weak ass kid is mine?”
“Middle school-“ Izuku muttered, Katsuki froze and his palms stopped exploding.
Kinumi continued with his explosions however and Izuku wondered why he kept it up- it must be using his energy…
“Oi kid- imagine it getting lower. The explosions- imagine they’re going out.” Katsuki awkwardly said. He knelt down in front of the boy and grabbed his still exploding hands. Katsuki closed his palm over the boy’s small hand and the explosions stopped. “Deprive them of oxygen and they’ll go out as well…”
Izuku could’ve told Kinumi that but he was too in shock that Kacchan had spoken to the boy, even after finding out what he was to him.
“Deku- this isn’t over.” Katsuki said, coming up from his position on the floor and turning around- walking off towards his dorm room.