Age difference is Y/n being 3 years older. (19)
Her Father's quirk is enhanced senses (the human senses are heightened for a selected period of time, but the selected period of time will be the same period of time for the consequences such as constant migraines and loss of sleep).
A few days later...
Y/n had been visiting Shigiraki until the fateful day she saw the police and heroes trying to assess the situation, a no go, Y/n was about to leave when she saw Shigiraki or at lease an outline of him in an alleyway out of the corner of her eyes before disappearing.
So for the other few days she met Toya at Sekoto peak until he finally introduced her to his family, which was only Rei so he could basically use Y/n as an excuse why he's sneaking out, Rei was still suspicious but she was happy that Toya had a friend.
Until that was when Shoto was finally born, Y/n knew that Toya would have a bad day so that night, when her parents slept, she went out to see him, and comforted him with some chilled yogurt, she could see he was crying.
"They don't listen! That man is so-!!! How can he just not even see that I have the potential of surpassing all might!" Said Toya as Y/n nodded listening carefully.
"At least you always understand me and listen, unlike my brother, sister, even mom." Said Toya as Y/n was eating some yogurt, nodding along.
5 years later......
8 years old and Y/n was now looking after Izuku and Bakugou as their official babysitter, Bakugou wanted to be independent of Y/n but even though he claims to be independent, he still clings to her, wanting her praise and attention.
"And you claim to be independent, cute." Said Y/n as she poked his forehead receiving some backlash from him.
"H-hey!! I can be alone!! In fact I'm leaving!" Huffed Bakugou as Y/n chuckled at him stomping away in a cutesy manner, meanwhile Izuku cling to her and wanting head pats.
"Who can resist that fluffy hair? Of course! I will be a fool if I DIDN'T!" Said Y/n as she yelled over to Bakugou who turned slightly to see Izuku receiving all of the attention, in an instant he ran back and demanded the attention.
"What's the magic word?"
"......please?.." Asked Bakugou as he turned away with embarrassment of stooping so low.
But Bakugou was calmed down by Y/n's hand combing through his hair. That is until Y/n got a notification from Toya, asking to meet up for quirk training.
"I got to go meet up with a friend, oh look Bakugou your friends are here!" Said Y/n as two kids approached, Bakugou and Izuku were happy that their friends were here, but Y/n knew better, Izuku was being bullied and he didn't even know it.
"I'll be right back, alright. Don't do anything dangerous." Said Y/n, the boys nodded and Y/n gave Izuku and Bakugou one more head pat before rushing away to see Toya.
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"You need to focus more quickly, remember your body is built to withstand the cold climate, make sure that fire is controlled!" Said Y/n as Toya was controlling his blue flames as Y/n held a giant stick.
When Toya was done, Y/n poked his head with the stick.
"Toya....." Said Y/n as she poked him with the stick.
"Stop poking me!!!" Said Toya as he put out his flames on his hair.
"We are gonna have a long time training you, and I have thought about an idea for your hero costume!" Said Y/n as she opened her backpack and got out her sketchbook.
Toya looked at her sketchbook to see what was basically a cool looking jacket with boots and pants.
"What's with the oversized Jacket?! I would look ridiculous!!" Said Toya.
"Give me that! Toya, this costume could withstand the heat of your flames and I imagine that it could cool you down with air conditioning added in, this could benefit you!!" Said Y/n as she poked him with the sick until he finally grabbed it and threw it away.
"Finally Toya, I thought you would never do that." Said Y/n as Toya did a blank face at her, Y/n snickered menacingly.
"IM GONNA KILL YOU!!!! GET BACK HERE!!!" Yelled Toya as Y/n began sprinting away, dying of laughter.
After playing with Toya, Y/n left to go back to Izuku and Bakugou, bringing back some dango.
Only to see Bakugou was about to use his quirk on Izuku who was terrified.
"Katsuki." Said Y/n as she walked closer as she held the bag of sweets, Bakugou looked and knew he screwed up.
"What are you three doing to Izuku?" Said Y/n as she tilted her head as they let Izuku go, the midoriya cling to Y/n's leg and cried.
After giving a scolding, y/n was about to tell his mother when Izuku pleaded not to tell his mom, Y/n reluctantly agreed, but didn't look at Bakugou, disappointed in him.
But she ended up giving him the dango after Izuku was still pushing to forgive Bakugou.
They went back to Y/n's home and she was reading some poetry about justice while Izuku and Bakugou were watching all might defeating villains left and right.
6 years later....
Y/n was in school her hair all tied up and studying more on quirk laws and investigations on crimes that had been documented. Until her teacher called her up to the front of the class.
"Wonder what that quirkless did this time..."
"Shhh! This gonna get good."
"Shut up! She'll hear you!"
Y/n got up to the front and looked at the teacher, wondering if she was getting something that could make her grades and achievements all paid off.
"Y/n you have received an internship from the Police agency, you can skip the process of high school to join it full time because of your IQ scores, or you can stay and finish your grade." Said the teacher, everyone looked shocked, even Y/n was a little taken aback, sure she knew that she received the highest scores but now this?!
"I am sure that this class will miss you."
'Yeah they'll miss me, because I help them with homework.' Thought Y/n as she saw the panicked expression of her classmates.
"Can I have the first option?" Asked Y/n.
"Sure there is a car waiting for you outside to take you to your internship." Said the Teacher.
'Gotta love the anime logic in this world.' Thought Y/n.
"Can't believe it...."
"A quirkless really beat us?!"
"Sayonara!" Said Y/n as she walked out of the school to see a police car already outside.
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"I'm sure you are wondering why we, the police force, offered an early internship to someone your age." Said the police officer, Y/n nodded.
"Yes, I would like to know." Said Y/n.
"Because you score higher than average and even interviewing your parents, your results showed all the same, you have potential of being a detective and not just a detective, a great defender of justice." Said the officer as he turned the corner and near the station.
"Like a he-" Said Y/n only to be cut off by a serious smile by the police officer as he nodded.
"A Hero indeed, but your training here will not be easy." Said the officer.
"I'll take my chances." Said Y/n as she looked at the station before another officer opened the door.
"Let's go L/n." Said the officer as Y/n was brought into the station.
People will soon hear of L/n Y/n the great detective of them all! Y/n was quick to study under the police agency for a few years before she knew it, 16 years old and she already surpassed her seniors.
But now when she returned home, it was dark, Y/n knew something was up, when she turned on the lights she saw cake and a banner.
"HAPPY PREMONITION!!!" Said her mother and father.
"You really didn't have to do this." Said Y/n.
"No you deserved it!" Said Izuku as he got out of his hiding spot.
"Tch! Here." Said Bakugou as he held out a small gift box.
"Seems like the kacchan I knew is not here, where is he???" Said Y/n as she looked around, Bakugou raged at her while she put up a thumbs up.
"There he is!"
"Get the hell away from me!!!"
After having some cake, Y/n was back out doing detective work, she was surprisingly on the news as being the youngest of in the police force, after that people were now recognizing her brilliance.
But her being quirkless was like a revelation, seriously? All they ask her is her quirk really just enhanced intelligence, really bitch? She's quirkless not brainless!
But now and again she's paired up with a pro hero for a case they need done, and she is poked with the same stupid question, are you really quirkless?
But Y/n felt a deep pain, that no one could ever imagine that a quirkless human being could have the intelligence for solving a hard case, Y/n wanted to show everyone that it didn't matter, quirkless, hero, villain, everyone is human.
So instead of having a forced smile, Y/n always appeared tired and forever in an annoyed scowl in the presence of anyone. Even when news reporters or even heroes plead for a smile, Y/n still kept her expression.
"Why do you appear so mad, when you show me and kacchan a smile?" Asked Izuku as Y/n was eating with him during a visit at school.
Y/n put down her chopsticks and looked at him with a soft smile.
"Because Izuku, I must show them that Quirkless people are too heroes." Said Y/n with a grin, Izuku blushed at her grin and happily nodded, he will never give up as long as Y/n was with him and giving him a thumbs up.
Ringing!*
"Detective L/n, what's the situation?" Said Y/n as she picked up the phone.
"Sorry to interrupt your visit, but we have a situation with a villain! He currently has hostages inside a hosu company building, and he's demanding......" Said the person only to trail off.
"Well? Continue, don't give me info if I don't know what he wants!" Said Y/n.
"It's You he wants, he said he would kill the hostages if you don't come!" Said the person, Y/n's eyes widened a bit, but it was then forced into a glare.
"I'll be there in 10 minutes." Said Y/n as she hung up, getting ready to leave.
"What's happening (n/n)?" Asked Izuku as his face turned into a worry.
"Threat happening down in hosu, said the villain is demanding my presence." Said Y/n as she walked away, Izuku feared for the worst but Y/n only pat his head.
"I'll be back before you know it, I am full of surprises y'know?" Said Y/n as she hugged Izuku before running away, Izuku's only hope was to have a quirk so he could never have to watch his friend go.
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Y/n drove quickly with her motorcycle, she was known to know Japan like the back of her hand, now the news reporters were surrounding her, asking questions.
Y/n only ignored them, knowing how annoying news reporters were in her past life.
She was dragged out of the swarm of news reporters and was escorted by one of the pro heroes, fat gum.
"Are you alright?" Asked Fat Gum.
"Yeah, nothing like a crime scene waiting to happen gets me pumped." Said Y/n as she walked towards the building, pulling out a gun, before dropping it.
"What are you doing?" Asked a hero.
"Getting rid of my weapons of course, besides I only need handcuffs." Said Y/n before walking into the building, opening the doors.
"DETECTIVE!-" Said a hero only for Y/n to shut the door.
Y/n looked at the building, nothing out of the ordinary, but she felt watched, she looked around to see a cockroach, pointing in her way, like it was watching her.
"So you want me to follow you?" Asked Y/n, the cockroach skittered away and stopped for a moment signifying a yes.
Y/n followed the insect until she saw a person or the figure, a lump of insects crawling over eachother reminding her about a certain creature in a certain scp foundation.
She saw people huddled in a corner, scared and looking like they will throw up.
A hand appeared out of the lump, shaped by bugs, then another, until the bugs disappeared into flesh revealing a masked man.
Y/n was about to move when the man pointed to the people, their back necks showed a few scorpions ready to sting them.
"Drop the handcuffs."
Y/n dropped them with little hesitation, the man quickly retrieved them and then out of the corner of her eyes a few bugs crawled up making her face lit up in realizing something only to feel a sting.
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The heroes saw the doors opening to see people putting up their hands scared for their lives and crying.
As the police officers brought them away, the heroes quickly ran into the building, only to see that Y/n was gone, only a pair of handcuffs were left.
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Y/n was blinded and she couldn't hear a thing, only muffled voices.
Maybe this was the end, she thought, accepting the end she bowed her head and awaiting the final swing of the axe.
A hand lifted her head up to look at them, or tried to, she felt a breath, a few more muffled noises before another touch in the face, before a terrifying pain broke through, everything hurts, Y/n broke out a muffled cry.
"Don't worry dear, it only hurts for a little bit, you may have to get used to your new quirk." Said a voice, it sounded like All for one, Y/n fell, her head bumped against the floor as she jerked her body.
Until she was knocked out.