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Heartbeat Paradox

Summary:

Escaping a dark future, 24-year-Old Izumi Midoriya makes a single change to the timeline that changes everything.

Now, 15-year-old Izumi Midoriya attends UA High School with memories of a different life messing with her head, including nightmares of the upperclassman with a scar over his eye, a brother who now has a powerful quirk, and feelings for her punk rocker classmate. Nothing will be the same for her again.

Notes:

Just a little heads up, I'm using the spelling for characters that's on the MHA wiki. Some characters like Iida are keeping their original spelling, though. I hope you enjoy.

Any feedback would also be greatly appreciated. I'm doing this with no Beta Reader, too. :)

Chapter 1: Prologue

Notes:

(See the end of the chapter for notes.)

Chapter Text

Izumi Midoriya darted between the rubble of the buildings, using float to avoid unstable pieces. It wasn’t the first time she had gone about this game of Cat and Mouse over the last 8 years. But it was the final time.

 

Arriving at what appeared to be a desolate car park, she knocked on a piece of scrap metal 3 times. How long had they been here now? 3 Months? Half-a-Year? She could barely recall. 

 

As she waited for someone to answer, she looked up at the grey sky that had never left since her fateful battle with Shigiraki 10 Years ago. The world was only a mess because she had failed. She hadn’t gotten through to Tenko in time, and All for One now reigned supreme as the Ultimate Demon Lord.

 

The memories of her failures echoed in her mind so much that she couldn’t even remember the last time she had gotten a full night of sleep. She couldn’t even remember the last time she had snuggled close with one of her loved ones.

 

Thankfully, before she could get lost any further in her musings about the world, the metal scrap was pushed out of the way. The jagged hands of Kirashima, her most manly of friends, wrapped around the corner of the metal.

 

Come on, Midoriya, we don’t have much time!”

 

His voice was almost as sharp as his body. Every word tore into her like thousands of knives. Of course, he didn’t mean it; he was just worn down like everyone else.

 

It was a never-ending nightmare that they were trapped in, but a nightmare that would hopefully end soon.

 

The pair walked down the corridors of their secret lair in silence, the corridors getting more cramped as they went down. Secret lair…it made them sound like villains. Scourging around, surviving on scraps, challenging society. In some ways, they were. In others, they were revolutionaries.

 

After a few minutes, they arrived at a medium-sized square room that just about fitted their remaining friends. A quick scan showed her Shoto, Sero, Mina, Kendo, Tetsutetsu Tetsutetsu, Hawks, Iida, Ochako and Tokoyami.

 

Kirashima softened his quirk and squeezed her hands “Nejirie and Rock Lock are out causing a distraction. We should hopefully have enough time to finish this, thanks to their sacrifice.”

 

Sacrifice

 

They weren’t even trying to pretend like it was something else happening now. Shoto approached them with concern on his heavily scarred face. 

 

“Did you get it?” 

 

She put a hand up to his face and ran a finger along a scar “I did.” 

 

Tightly she was pulled into a deep hug; something that still felt foreign to her from Shoto all these years later “Then the day has come.”

 

Sero ran over, his mask covering his face. “If you’ve got the items, then we need to get them ready for this. The sooner we can silence this dark world, the better.” The bag she was holding onto was snatched from her grasp and taken into a small back room.

 

None of them knew if their plan would work. How could they? But they had to try. It was the only thing they could do at this point…at least the only thing that didn’t include submitting themselves to All for One. Something that they would all rather die than do.

 

Shoto let go of her and started to walk towards the entrance before turning to face Izumu once more. “Remember you’ve got one shot. Save all of our friends.” 

 

Just like that, the Half Hot - Half Cold quirk user vanished from her sight for what would be the final time. 

 

In the past, in times like these, Izumi would consult the previous users for support. However, with their big plan needing everyone's strength, they had remained quiet over the last several months. It was a lonely existence, but they followed it as they wanted their plan to succeed.

 

The next couple of minutes were filled with heartfelt farewells. Hugs and tears were passed around the room; meanwhile, Izumi could only stare at the other room with worry. Soon she was left in the room all alone, her former classmate…her friends…no. Her family was leaving to defend them for as long as possible. 

 

One Final Time.

 

Glancing at the clock, she decided it wasn’t worth trying to recover much more energy. If they didn’t do this tonight, then they were either dead or trying to survive for another month. That might as well have been death anyway.

 

Approaching the room, A deep breath escaped her lungs, and she entered the room that would hopefully stop this dark world from ever being created. Giant Machinery took up a majority of the room with a large metal arch put together from scrap metal being held together by Sero’s tape. 

 

The arch was then connected to large pylons with at least 50 car battery cables on each one of them, which were all connected to two large batteries that were being charged up by Kaminari, who was well past his limit.

 

Yet her friend refused to give and kept giving more. The agony on his face was pushing past his fried brain, returning to him being fully aware of what was going on.

 

Near him, Yaoyorozu was lying on a thin mattress, looking deathly ill. Her ribcage showing through her skin, Deep bags under her shallow eyes, short hair that was greying and no muscle or fat to speak of on her entire body.

 

Yaoyorozu was the linchpin of all of this work. She was creating all the mechanical parts that needed to be new and fresh. She was the one who had created this entire lair that they were residing in. Kneeling next to her, Izumi pulled out a KitKat and said: “Here you go, Momo…eat up.”

 

Each bite was tiny, but the creation hero managed to eat the entire bar and open her eyes “Hey Zumi…you made it back in time.”

 

“Would be pretty lousy if I didn’t. How are you feeling?”

 

“Like someone with a steamroller ran over me.”

 

A light chuckle escaped Izumi’s throat. The sound was foreign to them all now, but it felt nice.

 

Bringing the mood back down, however, Izumi let out a quiet “Do you really think this is going to work?”

 

Yaoyorozu's onyx eyes stared right into Izumi’s emerald ones, and she said firmly, sitting up slightly, “You can’t have doubt now, Zumi. Remember why we’re doing this. All the work that we’ve put into this. All the people we lost. It has to be worth it.”

 

That was enough to reassure Izumi slightly, “You're right…Sorry. I think I’m just getting memories of all the times that Hatsume’s gadgets blew up in our faces back in first year.”

 

Kaminari chucked nearby them as Yaoyorozu cupped Izumi’s hand “I’m sure this baby of hers will work. After all, it’s a group project.”

 

“Damn right it is!” Hatsume screamed from the far end of the room as she finalised tinkering with the machine, as Sero helped her tape everything together. 

 

Finally, Izumi looked at the final hero in the room, Star and Stripe. Dressed in a simple white tank top and green cargo pants, she looked like All Might on the day that Izumi had first met him. If Present Mic were here, he would be talking about symmetry or something English-related, but that didn’t matter right now.

 

“You doing okay, Cathy?”

 

The former No.1 Hero from the States tiredly stuck her thumb up. “Just preparing to say goodbye to this muscular form.” 

 

Just like that, the room went silent as Hastume finished her work. The Silence was both unnerving and comforting. The oxymoron of it providing a small bit of humour, even if none of them laughed. How long they sat in this silence, Izumi couldn’t tell, but the longer it went, the more her nerves rose again.

 

“It’s done!”

 

Everyone jolted up to look at Hatsume, who turned around to face them. “The Portal is complete. We’ve got one chance at this.” 

 

Hatsume approached Izumi and said, “Izumi, when we start this process, you're going to need to focus. You're our greatest and only hope.”

 

A nod was the only thing that could suffice as Hatsume turned to talk to Kaminari. Izumi pulled out a picture from her pocket of the culture festival. It was taken the night after their big performance, and Kyoka had fallen asleep on Izumi’s shoulders on one of the couches in the dorms of Height Alliance. The picture had been taken by Shoto, who was trying to experience some hobbies, and he called it ‘cute’.  It was just before everything went to hell, so she didn’t have any other photos of her heart-pounding purple-haired beauty.

 

With a small kiss on the photo, she placed the photo away and said with as brave a voice as she could, “Are…Are we ready?”

 

Star stood up with a groan “I’m ready when y’all are.”

 

Kaminari, along with Sero, helped Momo to her feet. Izumi approached them, brought her friends into a tight hug and then got into position in front of the arch.

 

Hagure was at her keyboard typing rapidly; Izumi could only imagine the amount of code being written by the inventor's fingertips as they all got ready. Kaminari placed himself by the batteries once more; meanwhile, Sera was applying more tape to the contraption to hold it together. This jump would put the machine under so much stress that it would be a miracle.

 

Behind her, Star picked up two large cables and said, “From this moment onwards, I, Cathleen Bate, can act as a conduit and enhancer for the power required to power this device so that it works.”

 

The rule went into place at the sacrifice of her All Might-level stature. Not that she wasn’t still incredibly buff for a 40-odd-year-old woman. “Once I activate my next order, we will have only a couple of minutes before He arrives. Hatsume, it’s time to start the process. Yaoyorozu tell the rest of them to be ready. Izumi, it’s time.”

 

A neck twist and nod was all that Izumi could give her before Star placed a hand on her spine “From this moment, Izumi Midoriya can use this device to access her own timeline along with her quirks timeline with the purpose of saving Tenko Shimura and stopping this cursed world.”

 

The power surged through Izumi’s body, and all of the other users appeared before her as Banjo said, “Alright lass, we’ve got this.”

 

Through gritted teeth, she managed to respond, “It’s so much more than we’ve ever had to handle before.”

 

Behind the ghostly projections of her predecessors, the portals started to form, green swirls forming in the arch as electricity ran through the cables and table, through Star and as Kaminari poured even more electricity into it.

 

En then spoke, “That’s why we were here to help ease the burden.”

 

Before Nana finished, “So that we can right the wrongs of the past once and for all.”

 

The others nodded just in time for a loud explosion to shake the entire room…no, not just the room, the entire earth.

 

He was here.

 

No doubt her friends were confronting this great evil while she stood here worthless, waiting for a portal to open up so that she could run away. Just doing the small jumps made her feel like a coward who had failed, and here she was jumping decades into the past literally to escape this man…who would also be there when she got back.

 

The portal began to form into a proper shape just in time for His voice to echo through the halls of the lair. “Izumi Midoriya, it’s pointless to run any longer. Your fellow heroes were no match for me. It’s time for you to give my Younger Brother back to me, dear little sister. Let’s stop with these foolish games.”

 

Yoichi started to shiver and stare at the device, and Izumi could have sworn that she heard the 1st say as he clenched his hands together, “Please work.”

 

Then, just at the last second, as there was a loud bang on the door, the portal formed a solid crack through it. Her timestream was waiting just up ahead. She started charging forward as her friends called out, “Do your best!”

 

Her hand slipped into the time crack just in time for ALL FOR ONE to break the door down with one of his many quirks and to hear him yell, “No! I won’t let you escape me again, little brother!” 

 

However, it was too late for her mortal enemy to stop her as her entire body phased into the timestream. With one day on her mind, the day that Tenko Shimura’s quirk revealed itself for the first time.


24 years earlier.

 

Toshinori Yagi snapped awake, his breathing heavy as a great storm raged outside. It wasn’t the first time since he had gained One For All that he had a restless night like this,  and he was sure it wasn’t going to be the last. Watching the bolts of lightning strike across the sky, he was reminded deeply of his dream.

 

It started the same as always, his Master sending him away as she went to challenge All For One, and like always, he defied reality and went back to save her, and together the two of them, along with Gran Torino, defeated the Demon Lord.

 

However, this time, curiously, was different. Another person that Toshinori was unfamiliar with appeared. Yet despite being unfamiliar with this woman, he also felt like she was a kindred spirit. 

 

Snapping himself away from the memories of his dream, he forced himself to look at his clock; It was 5 am, Not much point in trying to get back to sleep at this point, he was going to have to get up in half an hour anyway to start getting prepared for another day of hero work.

 

His large muscles flung him from his bed, and he pulled on an overly large dressing gown to cover his body. The coffee machine poured him some much-needed caffeine while he continued to look at the storm outside. As he watched, he could have sworn he saw a bolt of Green Lightning crash through the sky and hit the ground.

 

Hmm, green, that was the colour of hair that the woman from his dream had; long, unkempt green hair that went down to the bottom of her back, Emerald green eyes that looked like they once glowed with optimism that had been stifled. Scars littered her arms and legs, as if she had been damaged by a quirk ill-suited to her body.

 

Then there’s what she said: “Everything is about to change, No.8. Are you ready for a brighter future, Toshinori Yagi? All Might?”

 

Placing his mug down after chugging the entire caffeinated drink, he rolled his arms. He could leave this mysterious woman to haunt his dreams, or he could look into it. Normally, letting things come when they were ready was his style, but there was something about this lady which urged urgency. If anybody could track down this mysterious woman from his description, it would be Tsukauchi.


Izumi gasped as her feet touched the ground; it felt like her entire body had been disassembled and reassembled a thousand times over in mere seconds. But it had worked. She had escaped the rotten future that she lived in.

 

Right this very second, she was a small baby, only a matter of days or weeks old, about 100 or so miles away. The distance between her and her baby counterpart would hopefully be enough to stop her from forming into her younger self's soul too quickly. That’s why they had chosen Tokyo after all; not only was Might Tower here, but it was also where the Shimura household was. 

 

Just trying to get her breath was hell. Every breath hurt. Is this what Kachan felt like on that day when he faced down AFO? Or what All Might lived through every single day after their fated battle? They were far stronger than she could ever believe.

 

One foot at a time was the only way that she was going to get through this. Ignore the pain; it was temporary compared to the suffering that she had just escaped. 

 

“One for All: Full Cowling: Float!”

 

The energy coursed through her body, and sparks of green electricity shot from her body, and she launched herself into the sky. If she hurt this badly now, then she needed to reserve as much energy as possible.

 

Nana appeared on her shoulder “How are you holding up, 9th?”

 

“I’m holding together. Do you remember where your son’s house is?”

 

“I do. According to your friend Iida’s research, the house was only a couple of miles away from All Might’s HQ, so if we get there, we should be able to find our way better.”

 

“Right.”

 

Pushing her arms behind her, Izumi forced her body forward with Air Force. Every snap of her fingers made it feel like she was breaking all of her bones all over again, like when she had first inherited One for All. She had forgotten what that pain felt like.

 

Unfortunately for her, her strength was fading faster than she hoped, and instead of landing gently next to All Might’s tower, she crashed into the trash bin next to it.

 

“Okay, Nana, where to next?”

 

Then she noticed All Might in his ghostly form was standing there too, “Heya kid, just go and ask my receptionist where to go. It will save us some time.”

 

Then, just like that, he faded back into her. Was it the proximity to the building that had dragged him out? She hadn’t seen his form outside of group meetings for years.

 

Picking herself off the ground and clearing a piece of banana skin off her tattered hood, she entered Might Tower and was greeted by a large sign that read:

 

WELCOME TO THE ALL MIGHT AGENCY. WE STRIVE TO HELP. NOW GO BEYOND, PLUS ULTRA!!!

 

Then underneath the sign was the reception, and although she couldn’t see the receptionist, she could hear his voice as they spoke to the police officer in front of her, and it took everything she had not to choke up.

 

“Good morning, Detective Tsukauchi. I’m assuming Master All Might called you in for you to be here this early? He’s got a wicked sense of humour when he wants to.”

 

“That's right, Nighteye, I’m surprised you're in so early in the morning. It’s barely 5:30.”

 

“Master All Might needed someone on duty overnight, and the rest of the team had already gone home. I was more than happy to stay late and help out.”

 

It was Nighteye. She had never seen him so young. He must have been fresh out of school or even still in it at this point. All might must have known when he sent her in here that Nighteye was going to be here. Why else would he have faded back into her so quickly?

 

The detective walked away, and Izumi was soon face to face with one of her former mentors. The tall, Langly man stretched out one of his langly fingers and motioned for her to approach. His hair was entirely green, so he hadn’t dyed any of it yet to match All Might, but she could see his All Might slippers on one of his feet from his crossed legs.

 

“How can I help you, Ma'am?”

 

Ma’am? By the quirks…she was older than Nighteye right now. That felt deeply wrong. This 17-year-old wouldn’t even make it to 35 in her timeline, but hopefully, if she succeeded today, he would live a long and full life and make up with All Might in the future.

 

“Oh… erm…Hi there, erm, I’m new to the city, and I’m looking for a friend's house, but my phone died, and I’m completely lost as to where I am. I was wondering if you could help me?”

 

“A civilian needing help, in those clothes? I highly doubt it.”

 

Izumi threw her hands up into the air “I am a Pro. I’m just on holiday and have none of my communication gear. I only threw my spare outfit on cause I don’t want to ruin my good clothes.”

 

The man leaned forward, his long neck creeping towards her as he studied Izumi up and down before he flopped back in his seat “Okay. So do you know what your friend's address is called?”

 

“I believe it’s something like Shimura Manor or something?”

 

“Hmm, let me see, I can look up a list of people called Shimura on the database; that should help. Can you just confirm for me the name of one of your friends' family?”

 

Nighteye was testing her. If she didn’t say a name, it would come off as suspicious, like she was trying to launch an attack against the family. She would say Tenko, but it would also be creepy and suspicious if she said a kid's name. That was when Nana came in clutch and rested a hand against her shoulder “Kotaro”

 

“Kotaro Shimura.”

 

The lanky man typed and said, “Ah, here we go. Is this the address you're looking for?” 

 

Turning the computer around, he showed her the image of a house, and she recognised it from the time she had managed to enter Tenko’s consciousness. “That’s it.”

“Brilliant, well, to get there from here you go…”


10 Minutes Later

 

Izumi was grateful to young Nighteye for being so thorough in going through the directions because it ensured that neither she nor the predecessors got lost. 

 

Now she was almost at the house just as the sun was starting to rise. The feeling of worry started to build back up in her body, and she felt sick. She could stop everything in just a couple of minutes. Reaching a hand out to a child in need was the essence of being a hero after all.

 

Then she arrived at the house, and it felt like she was back in her own timeline; the house was destroyed. Not quite decayed, but it was clear she had already arrived once Tenko’s broken quirk had revealed itself. Through the rubble, she could see the decayed bodies of the Shimura family. If she could find Chisaki, she might even be able to restore some members of the family if they acted quickly enough. 

 

But right now her focus had to be on Tenko. Floating over the debris, she looked at the back garden where she remembered Tenko to be from the memories she had seen, but there was no sign of the boy. That didn’t mean all hope was lost, however.

 

Moving closer to the ground, she could see a series of bloody footsteps moving away from the house. While horrifying, this might be exactly what she needed to find the poor child. Once she landed on the street, she stopped floating and started to follow the trail of blood. Feelings of resentment for the boy who turned into the man who had killed everyone that she loved started to rise once more. Her dear Kyoka was gone because of this monster. 

 

Drowning out those thoughts was harder than she wished it was, but resentment was a strong emotion, and she had 10 long years to grow such a feeling inside her. 

 

Slowly, the blood trail began to disappear as she neared an underpass. The sound of sobbing echoed in her ears, and suddenly the resentment washed away from Izumi. It was the sobbing of a Confused, abused, lost, and no doubt hungry child; how could she ever hold resentment for a child going through that?

 

Stepping towards the source of the sobbing, she caught a glimpse of the light grey hair of Tenko Shimura, holding his knees, crying his heart out. When she got close enough, the young boy heard her footsteps, and his head darted up.

 

The boy shuffled away “What…what do you want…are you here to punish me?” Her heart broke into a million pieces, and next to her, Nana Shimura started to sob uncontrollably. Gently, Izumi reached her hand out as she said:

 

“There’s no reason to worry anymore, child. Why? Because I am Here to help you.”

 

Tenko looked up, surprised “Help me?” His throat was incredibly raspy, and it made Izumi wonder how long he had been crying.

 

“That’s right. Are you hungry? It looks like you’ve been out here all night.” She reached into her pockets and pulled out a small breakfast bar “Here you go.”

 

Reaching her second hand out, she offered him the bar, and it was snatched from her hands and within seconds, he was stuffing his face with it. Even from the small bit of food, he looked a little better.

 

He then asked, “My family is hurt…I don’t know what happened.” 

 

“I saw. It looks like your quirk had a violent awakening. But Deku is now here to help you. If you let me, we can take you to some very safe people, and you can eat a buffet, find out about your quirk, be safe, and we can potentially help your family. But only if you're willing to grab my hand and come with me?”

 

It was as if Tenko had never seen true compassion before, and her shattered heart continued to break. No Wonder AFO had been able to influence and darken his heart so hard. He was a broken, lonely child who just needed someone to reach out and save him.

 

Unclurling her hand to let him grab it, she braced herself for potential decay, but it never came. His fingers wrapped around hers, and she was fine. Hatred was what made his quirk activate, and he had no reason to hate her.

 

Helping him to his feet, she lifted him, holding one arm under him and allowing him to wrap his arms around her neck. “Everything’s going to be okay, Kiddo. Do you mind telling me your name?”

 

Tenko…I’m Tenko Shimura.”

 

“Well, it’s nice to meet you, Tenko. I’m Izumi. Now let’s say we get out of here, hold on tight.”

 

Launching back into the air with Nana’s Quirk float, she activated Black Whip to hold onto Tenko better and started to make her way to the nearest police station. As he floated, she looked over and saw a look of amazement on the young boy’s face. The Look of terror and anger vanished as he floated up in the sky. The boy was born to have a flying quirk, and that monster All for One had stolen it from him.

 

The further they went, the more the grin on the boy grew, and his eyes shrank to normal size. Hopefully, if she got him under All Might's or Gran Torino’s care, this boy would be safe from that monster for good.

 

Arriving at the local police station, they gently landed. People were now out and about, staring at her and Tenko, worried before scurrying away from them.

 

Tenko asked sadly, “Is it me that they're running away from? Is this my punishment?”

 

Placing him on the ground and crouching to be on the same level as him, cupped his cheeks, wiping away a small part of the dried blood. “Nobody is punishing you, Tenko. You’ve been through something traumatic…something that tore your quirk open. They're probably running away from me; I look quite villainous with my current costume. Now we’re going to go in here, get some people to talk to you and then get you cleaned up. Okay?”

 

He nodded, and she ruffled his head and gently took his hand. Izumi was finally saving the crying child that she had seen within Shigiraki’s mind all those years ago, and she wasn’t going to let him go now.

 

Entering the police centre, she was quickly greeted by a concerned receptionist who leapt from her desk, “Oh my god, Ma’am, are you two okay? You both are covered in blood.”

 

With a smile that would have made Lemillion proud, she said, “I’m fine, officer, but young Tenko here has had a rather dangerous quirk awakening. Could somebody help clean him up, and could someone get Detective Tsukauchi here ASAP and tell him to bring Toshinori Yagi and Sorahiko Torino with him, and tell him it’s regarding Nana Shimura?”

 

“Of course.” 

 

The woman scrambled for the phone; meanwhile, Izumi bent down and said to Tenko, “In a few minutes, someone is going to take you to get tidied up and changed into fresh clothes. But don’t worry, I’m going to be in the building. I’m just going to start sorting things out for you, and then when you're done, you can come and join me. Okay?” 

 

That ended with Tenko hugging her tightly until a young cat officer entered and took him away.


When Toshinori Yagi heard his friend mention his Master’s name, he wanted to rush over to the police station. Especially as this person knew his and Gran Torino’s real identities. Nobody outside of this room knew his real name. 

 

However, as Tsukauchi suggested, they waited for Gran Torino to arrive at Might Tower before they acted on anything else. After all, Sensi Sorahiko knew Nana Shimura better than All Might, having been one of her closest friends from their school years until Nana’s death about 20 years ago.

 

Once Gran Torino arrived, All Might carried his friend and mentor to the police station, where they landed within seconds. His fists were tight, and it was only when Gran Torino said “Toshinori. Calm your jets.”

“Of course, Master.”

 

The three of them entered the police office to hear the receptionist gasp as she saw him, and he gave her his trademark grin that won over nearly everyone. Yet the smile was a hollow one. Who was the person that they were meeting, and what did they know about Nana Shimura?

 

Being led through the corridors of the Police Station, Toshinori noticed his mentor start to tense up more. This was bringing up bad memories for the older man. In fact, it looked like Gran Torino was starting to shrink in stature. Years of grieving were starting to wear away at his body.

 

Then there was the subject of the green-haired woman from his dream. They had only just started discussing it when Tsukauchi had gotten the phone call about this. But from his brief conversation with his new sidekick Nighteye this morning, it did seem that someone resembling this dream woman had entered his building this morning for some reason.

 

Finally, they arrived at a meeting room, and the officer opened the door wide, revealing a Woman with long, unkempt green hair sitting on a couch, with emerald green eyes that held a small sparkle that lit up when her eyes locked on him and Gran Torino.

 

It was her. The Mysterious Woman.

 

Jumping to her feet, the woman said, “Detective Tsukauchi, All Might, Gran Torino. Thank you for coming so quickly.”

 

Then she bowed, and Toshinori could have sworn the woman muttered: “Damn, he’s tall.”

 

Understandably to anyone, Toshinori chose to waste no time once the door shut, and it was just the 4 of them left “Who are you, woman? Who did you know our secret identities? Why did you invoke Nana Shimura’s name?!”

 

The woman put her hands up and said, “Allow me to explain. If you're implying that I’m an agent of All for One’s, then that couldn’t be further from the truth. My name is Izumi Midoriya. Code Name: Deku.”

 

Toshinori was put on difficult footing: “How do you know about All for One?” 

 

A deep breath escaped the woman’s mouth. “Because, Toshinori Yagi, we are both torch bearers of the sacred flame passed on from weilder to weilder in an effort to defeat him.”

 

Couldn’t it be possible? Could it? There was no way this woman could be a wielder of One for All. The woman continued, “The Power of One for All, passed from the brother of All for One down the generations in a desperate hope of survival in the belief that it would defeat All for One. You had the flame passed to you from your Master, the 7th user, Nana Shimura. You are the 8th Holder and the current holder in this time period.”

 

Before Toshinori could lose his cool, his master stepped in, “What are you implying, girl?” 

 

“As I said, my name is Izumi Midoriya. What I didn’t say was that I’m the 9th user. I’m your successor, All Might, and I need your help before I vanish from reality.”

 

Now that was something that none of them expected.

 

“Right, let me explain fully. I’m a time traveller. In this time period, I am technically a Baby, only a matter of weeks or months old. About 14 years in the future, you pass One for All to me. A couple of years later, the world fell into ruins; my classmates and I spent roughly 8 years just surviving, trying to figure out a way to save the world.”

 

Tsukauchi was the one to interrupt her: “You’re a Time Traveller? But how?”

 

“I’ll explain in a moment. All for One reigned supreme over the world. Even with One for All at 100%, along with the quirks of all the previous users, we weren’t able to defeat him. So we decided that the only way to stop him was to stop him from rising from the ashes at all. It involved saving a boy who had his entire life manipulated by this Demon Lord. It took one of our best engineers, a Quirk that had been passed from generation to generation, yet remained the same, and someone with the power to rewrite the rules of reality, but we managed to create a tear in the fabric of Time. After making small jumps to keep ourselves alive for nearly a year, we finally put a plan in place, and I jumped 24 years back in time.”

 

Gran Torino spoke up again, almost like the pair were trying to stop Toshinori from speaking his mind, “Even if we were to believe your story about Time Travel, and mind you, I still don’t. What does this have to do with Nana Shimura? That’s the name you summoned us with, girl.”

 

“It’s because the boy I’m here to save is Nana Shimura’s grandson. Tenko Shimura.”

 

No.”

“No, it can’t be.”

 

“All for One orchestrated his entire life, stole his quirk and gave him an incomplete destruction one. Last night, Tenko was thrown out for discovering a photo of his Grandmother. The stress from everything activated his quirk, and he accidentally killed his family before his quirk overwhelmed him and he intentionally killed his father, Kotaro Shimura.”

 

The trio were silent, and All Might fell to his knees in shock.


Izumi Midoriya was devastated to see her teacher fall to his knees, but it was the only way the full story could be told without All Might getting trigger-happy. 

 

Gran Torino’s reaction hurt even more… “No, Kotaro wouldn’t…”

 

Izumi looked down at the ground “While you and Nana Shimura made the correct choice for his safety…All for One found him and chose to twist his emotions into resentment for heroes and made him harsh with Tenko, who wishes to be a hero.”

 

It seemed to break the pair of pro heroes. So Izumi carried on, “Make no mistake, this was all in All for One’s plan. He planned on using the Society's reliance on you, All Might, to make people null on helping the child, then he would appear and mould Tenko into his perfect soldier. But that’s why I am here. To stop him from continuing this plan now.”

 

The door opened to the room, and a cleaned-up version of Tenko ran into the room wearing a fresh T-shirt and shorts that reminded her of her own clothes when she was a child with Kachan. “Deku! They gave me a T-Shirt that has All Might on it! I’ve never got to wear something so cool before.”

 

Izumi couldn’t help but grin as she ruffled his wet hair, which was returning to its natural black colour. This child’s soul was not lost yet.

 

“Well, Tenko, you look so much better now. Now if you turn around, you’ll never guess who’s behind you.”

 

The kid turned around and squealed, “Oh my god, you’re All Might…You're really him.”

 

In seconds, Izumi watched as All Might put on a brave face for Tenko “It’s nice to meet you, young man. Your friend over there was just starting to tell us all about you.”

 

“Deku saved me! I was scared and alone, and she reached her hand out to me!”

 

Before Tenko could ramble or get himself worked up, Izumi tapped the couch next to her and said: “How about we all get settled on the couches and we don’t have too much time to discuss them?” Tenko ran over and leapt onto the couch, snuggling into her side.

 

Across from her, the three gentlemen got seated, and it took everything Izumi had not to snicker at the three of them trying to fit with All Might’s massive frame. 

 

However, before she could say anything, Tsukauchi looked her dead in the eyes and asked, “Miss Midoriya, are you okay? Your arm is?”

 

Looking down at her two arms, she noticed that her left arm was becoming cracked and crystallised. The aftereffect of time travel. It wasn’t the first time she had seen her arm like this. Unfortunately, Tenko noticed before she could reassure anyone and said, “Did I do that to you…I don’t want you to go; I don’t want to lose anyone.”

 

She brought him in closer to her and said, “Hey, listen to me, kiddo. This isn’t you. You’re being extremely strong for me right now, so continue to be so, please.”

 

Tenko nodded and turned away from looking at her arm, but she could still see him catching glances.

 

“I’ll be fine, Detective. I’ve got enough time to finish my job here at the very least, but just for all of our comfort, I would like to move all of this along. We need to talk about Tenko’s Guardianship.”

 

Tsukauchi muttered, “Standard process would be for the kid to be placed into care.”

 

Izumi shook her head “Absolutely not. All for One has connections in care homes across the country, and I doubt he will want to let Tenko go. No, I believe it’s best if Tenko here come under either your care, All Might or your Gran Torino.”

 

“Us?” came from both of them.

 

Nodding, Izumi carried on, “Two Major reasons. No. 1, both of you are aware of All for One and the threat he poses. Both of you are in a much better position to protect Tenko. I do not believe for an instant that All for One will accept losing Tenko and will attempt to get him back. No.2 The Pair of you are the closest thing to family he has left. Gran Torino, you knew Nana Shimura better than anyone else, and All Might, you’ve called her your mother before.”

 

That was when it finally clicked for the two of them that what she was saying was the truth. All Might had told only Gran Torino about how much Nana Shimura meant to him. 

 

“No.3 I wasn’t going to do 3, but even if I can bring back some of his family, which there is no guarantee that I can do…He can’t stay with them. Especially with his quirk at the moment. He needs someone to look after him.”

 

All Might grinned, “Okay, but what about yourself? The way you're acting, you seem to care for the boy.”

 

Izumi looked at her feet, ashamed “I would, after all, saving a lost child is the essence of being a hero. But not only will I not be able to look at him as he grows older because it’s his face that hurt those that I love…I won’t even be here for long. You can see my arm fading as we speak. Two Izumi Midoriyas can’t exist at the same time. My Past self will soon absorb my soul.”

 

Gran Torino sighed as he stood up, and seeing Gran Torino be so tall freaked Izumi out. Where was the little goblin who had taught her?

 

“So what you're saying is that it has to be one of us. Then it should be me.  You wouldn’t even be here if it wasn’t for me failing to convince Nana that it was the wrong move to put Kotaro up for adoption. It’s also not fair to Toshinori. He can’t take all the time in the world off from being the symbol of peace to look after the child. I’m close to stepping away from active Hero Work anyway. It’s the least I can do.”

 

Tenko’s eyes were just darting between Izumi and Gran Torino, not quite understanding what was going on. “Detective Tsukauchi, can I assume that you would be able to deal with the paperwork?”

 

The detective ran a hand through his hair, and the man looked like he had aged 20 years in the half hour he had been here. Not that Izumi could blame him. It was a lot to take in. “Probably, although the hero commission will probably have to get involved because this is way above my pay grade.”

 

Izumi flinched as the crystallisation of her body spread across her shoulder blades. “Right, we have a few more things to discuss about Tenko…then I need to pay the head of the Shie Hassaikai a visit.”


About two hours later, Izumi left the police station, now dressed in a suit that one of the officers had bought her. She couldn’t even remember the last time she had worn something that wasn’t her work suit. Maybe 6 odd years ago? There’s no way it had been the full 10 years, right?

 

Little Tenko had fallen asleep on the couch after having been introduced to Gran Torino properly. The older pro had spent time telling the kid stories about Nana Shimura, which had made the ghostly projection tear up while they listened. Izumi doubted the child had slept since last night, too, so it was a miracle he hadn’t fallen asleep before then.

 

All Might had gone on his way to talk to David Shield, who was most likely on I-Island, sleep-deprived from Melissa being so young. 

 

Then there was Tsukauchi, who was dealing with all the paperwork and had managed to book her a meeting with the Boss of the Shie Hassaikai. She hadn’t returned to that place since they failed to save the young girl who was kidnapped by Overhaul. She wondered if fate would have turned out differently if they had managed to save the girl.

 

Would Izumi have been out of action for so long during the Hospital raid? Would Lemillion have lost his quirk?

Would Nighteye still be alive?

 

All hope had been lost to save the girl when Tomura Shigiraki removed Overhaul’s arms. No quirk could reassemble her. 

 

Yet here she was, travelling by train to meet the head of the Shie Hassaikai so that she could use Overhaul’s quirk to hopefully save Tenko’s family and potentially even save Tenko himself from the copied quirk. The irony of the situation was not lost on her.

 

Every so often, she could feel more of her body crystallise. It was odd; she could move perfectly normally, yet the body parts no longer felt like they were there. Her left arm was now fully green crystal, while a small diamond jewel had formed on her right wrist, suggesting she wouldn’t have much time before that arm went to.

 

As she got off the train, she was greeted by a police officer who, according to Tsukauchi, was one of the only official contacts to the Yakuza within the police force. The pair walked in silence to the building, which was in much better shape than the last time she had been there, and were swiftly led to the Boss’s room.

 

The boss was writing a letter when Izumi and the officer entered. From what Izumi could see, it was in traditional Japanese. The pair waited for him to finish writing before taking a seat and allowed the boss to speak first.

 

“Now this is interesting. It’s rare for the police to call such an urgent meeting these days, and I’ve certainly never seen them invoke All Might’s name as a threat before. So what can I do for you?”

 

Gulping, not wanting to screw over Yazkuza/hero relations, said, “I apologise that the police were so forceful in organising this meeting, but we need your help. It’s regarding your Ward Kai Chisaki.”

 

The man raised his eyebrow, so Izumi carried on, “Before you took him in, he was at an orphanage, right? Well, his quirk was copied, meddled with and given to another child a couple of years ago.”

 

The man's eyes widened “You mean some child can create and destroy with a touch of his fingertips?” 

 

Izumi nodded, “Yes. Except this poor boy can’t restore what he destroys. He was given a broken quirk that doesn’t match his body. It activated last night, and he killed his entire family.

 

The Boss was horrified “That’s terrible. But how does this relate to needing our help?”

 

Izumi cracked her head side to side. “We’re hoping that if we get your ward to this boy’s family quickly enough, that he might be able to restore them, seeing how their quirks are connected. We also hope to take a sample of your wards dna and see if we can return the restoration part of this quirk to the young boy so at least he can undo the damage he was going to cause.”

 

The boss shut his eyes before snapping his head up “We will help you. The Yazuka may involve itself in shady business from time to time, but we aren’t monsters. I will go and grab Kai immediately and meet you at the front.”


Just like that, they were travelling back to Tokyo, with members of the Shie Hassaikai keeping an eye on the Boss and his ward surrounding them from all directions. Surprisingly, Izumi felt completely safe in their company. Apparently, they didn’t consider her a big enough threat to the boss.

 

Chisaki looked as if he had already developed a hatred of blood and germs as he glared at an unknown liquid on the ground near him with disgust. 

It also didn’t take them long to get to the train station in Tokyo to reach the former Shimura household. The boss was shocked by it “It’s like someone with a gigatification quirk tore through the house.”

 

Slowly they walked over the rubble, and Chisaki said under his breath, but just loud enough for Izumi to hear it, “Quirks are a disease. This proves it.”

 

Through the rubble, they found the remains of the Shimura dog, and the boss placed a gentle hand on Chisaki “Do your best, Kai.”

 

The glove slipped off the 12-year-old boy’s right hand, and he touched what remained of the dog’s tail. The body matter of the dog under the rubble rose to rejoin the tail. Then, about a minute later, a perfectly healthy dog was running around everyone, sniffing everyone. The Dog had a particular interest in Izumi, who had Tenko’s scent. Even though Tenko had killed the dog, the dog didn’t seem to care.

 

This was when Izumi noticed how tired Chisaki was. He hadn’t trained his quirk to do large-scale reconstructions like this. It was a far cry from the man she had fought in her first year at UA. This meant she had to prioritise who to try and bring back next.

 

Not that the decision was difficult; it had to be Tenko’s sister. It wasn’t fair that a little girl was going to stay dead.

 

They actually used the dog to help find the remains of the girl, and once more, Chisaki placed his bare hands on the bloody remains. This one took longer; her body mass was a fair size larger than that of a dog after all. But after 5 minutes, a fully breathing 7-year-old Hana Shimura was alive again, although unconscious.

 

Chisaki was really sweating now, and it looked like he was barely standing. But the future Maniac was doing a good job using his quirk even at such a young age. The Boy looked at her and said with a gasp, “I think I can maybe do one more? If that.”

 

Nodding, she considered who the final person to save should be. It definitely wasn’t going to be Kotaro. Even Nana agreed he shouldn’t come back. The grandparents were an option, but they had also lived a pretty full life. That left only one other option: the Mother.

 

Thankfully, the mother had been decayed by Tomura not too far away from Hana Shimura, so it was pretty easy to find the few bits of flesh that remained of her. Chisaki got to work, and they all waited in anticipation. Time ticked on as Chisaki worked, everyone holding their breath, hoping this would work. It was clear that Chisaki was struggling, yet every time it looked like he was about to falter, he looked at the Boss, then returned to what he was doing, even more determined.

 

Finally, an almost complete body appeared in front of Chisaki, and the boy stumbled to the floor, staring at the blood on his hands with disgust. “I’ve done all I can; there’s not enough matter left of her for me to reconstruct her right hand.”

 

Snap

 

The boss clicked his fingers, and Yakuza members jumped in with bandages to wrap the older Shimura’s wrist to stop the bleeding.

 

Izumi approached the Boss and put her hand out to shake. “Thank you for doing this, sir. I can’t believe I’m saying this, but I’m in your debt.”

 

“Don’t be silly. The Yakuza might not be a powerhouse anymore, but we can still help people when they need it, even if we have to play dirty. Now about the second part of your request, I do think it might have to wait until Kai wakes up.”

 

The handshake was one of firm respect as Izumi replied, “Don’t worry, David Shield will do it in a couple of days. It shouldn’t take him long. He’s a genius after all. As for me, this will probably be the last time you see me for a long, long time.”

 

“Before you go, where do you want my people to take these two and the dog? Also, what’s your name?”

 

“Oh, the officer who came with us has the name of the station I would like them dropped off at. As for my name, I’m Izumi Midoriya.”

 

As she turned away, she thought she heard the Boss mutter, “Midoriya, you say…could she be related to Hisashi?” But she was certain she was just imagining things.


Returning to the station, her body was almost entirely made up of crystal now; everything but her head and feet. She knew she didn’t have much time, which is why she was relieved to see All Might when she entered the room.

 

The large man approached her and said, “David was more than happy to help. Did you manage to save the family?”

 

Giving her mentor a sort of look, she responded, “We saved the mom, Sister and dog.” 

 

He nodded and said, “You did your best…”

It was clear to Izumi that something was on the large man’s mind, and she leaned in slightly “Are you really my successor?”

 

She could nod or say yes. But instead she chose to reach out and grab his large hands “Open yourself up to One for All. Trust it, and you will see the truth.”

 

All Might shut his eyes, and after a few seconds, Izumi could feel both of their copies of One for All intermingling between them. The past users are making themselves known to Toshinori.

 

He stepped back with a gasp. “You really are my successor.”

 

Izumi nodded, “And in 14 years you will need to find me and give One for All to me.”

 

“Where will I find you?”

“Don’t worry about that now; all you need to know is that you will find a Quirkless, green-haired girl who worships the ground you work on. You’ll know it’s me.”

 

“If you say so, Young Midoriya.”

 

She hadn’t heard that said to her in so long, and it hit her like a gut punch.

 

That gut punch got even worse when Tenko ran over to her, “Deku, Mr Sorahiko was telling me all about some of the adventures he had with my grandma. She sounded so cool. I can’t understand why my daddy didn’t like her. I can’t believe I’m going to live with someone so cool! You’ve got to come and visit us.”

 

That was all it took to break the dam that was keeping her tears at bay, and as she crouched down, she said, “I would love to, Tenko, and one day I will but I’m about to have to go away for a long, long time, and next time you see me it might not be in the way you expect but we will meet again. So, in the meantime, promise me that you will never let anyone twist your heart and tell you that you can’t be a hero. Because I see the heart of the next No.1 inside of you.”

 

The kid started sobbing as he held onto her tightly, “I promise, but why do you have to leave? " You're my hero, Deku.” 

 

“That I am, and knowing I’ve saved you will make the next thing I need to do so much easier. Take these words to heart, young Tenko. The essence of being a hero is reaching a hand out to those who are lost.”

 

Then she hugged him back tightly, looking at her two mentors. Slowly, Tenko pulled away from her, allowing her to stand back up to be eye level with All Might, Gran Torino and Tsukauchi.

 

“Thank you, all three of you. I know today has been confusing, but thanks to you all, I know my mission will have succeeded, and I can go into the next bit in peace.”

 

Gran Torino said in his normal, stoic voice, “So what happens next?”

 

“My soul will merge the version of my soul that’s meant to exist in this time. My memories and personality will most likely remain dormant for many years until the body is ready to accept them.”

 

“So this very well may be the last time we see you then. Thank you for saving Shimura’s Grandson.”

 

“You can thank me for that in the bright future ahead of us, old man.”

 

The 4 adults chuckled, and then Izumi turned away. “Take care of yourselves, and don’t ever forget to go beyond Plus Ultra.”

 

Just like that, she walked out of the station and made her way to an alleyway. It was getting to the point where it was almost impossible to walk as her body became fully crystallised.

 

6th Quirk, Smokescreen”  Purple smoke sprang from her body as she slumped down against the wall of the building, and she looked at the predecessors who were surrounding her. “Thank you for allowing me to access your quirks. We couldn’t have done this without you.”

 

Yoichi was the only one to speak, “No, that you ninth. Without your perseverance, we would have been taken by my brother. It was you who made such good friends who were willing to help in our mission. Hopefully we will all meet once again.”

 

Then they vanished as her eyes got covered over by the crystals. Kyoka, Momo, Kaminari, Mom, Iida, Shoto, Tokoyami, Ochako, All Might. She did it; she actually saved Tenko.

 

Then her entire body crumbled into tiny pieces of green dust, her soul shooting across the country, crashing into a baby girl with small tufts of green hair, squirming as her twin brother wailed next to her.


Elsewhere

 

“So, someone had decided to come travel to this time. Good Doctor, I think it might be time for a change of plans. I get the feeling that Tenko Shimura is a pathway that’s been closed off to us. Such a shame.”

 

“Are you sure, sir? If we unleashed one of your loyal servants, I’m sure we could track the boy down.”

 

“With this temporal quirk I absorbed a couple of years ago, I can tell whoever this Traveller is has come from the future, which means they have tried to flee me, the great demon lord. With Tenko’s disappearance this morning, it’s not hard to assume that they’ve tried to take him off my charcuterie board. It is what it is.”

 

“Of course, old friend. Shall I try and keep tabs on Tenko just in case in the meantime?” 

 

“Hmm, I see no reason not to. Go ahead. In the end, this is all to reunite with my brother after all. I don’t mind waiting a couple more years.


10 Years Later

 

Izumi twisted and turned in her bed; her head hurt so much! Images of buildings collapsing echoed around her head as a woman with long green hair held onto another woman with long dark purple hair who was bleeding heavily. 

 

No matter how much Izumi tried to call out to the women, it was like her voice was gone. Reaching a hand out, the girl hoped to grab their attention, yet purple tendrils leaking some kind of fume escaped her hands instead.

 

Crunch

 

Izumi snapped awake, smashing her head into the top of her bunk bed, making the pain in her head even worse. Clutching her forehead, trying to keep the tears in, she looked for the sound that woke her up to see the remains of her All Might clock smashed against the opposite wall with purple smoke extruding from it.

 

What just happened?

Notes:

Hope you enjoyed. I've had this idea in my head for a while and have really gotten back into MHA over the last few weeks. This is like 99% set up for the main story, but it's an important set-up for how this world is different to the main canon.

A couple of small things: although the tags say Bakugou isn't in Class 1-A, that doesn't mean he isn't a major player.
The Second Izuku Midoriya ship tag is referring to Izumi's sibling, who will be different personality-wise from canon Izuku, even if he does ultimately share the same name.

Hopefully i get another couple of chapters out soon. Bye for now

The Name of the story has been updated to just be Heartbeat Paradox, As I've chosen to remove the full MHA part of the name (It wasn't needed really)