Issues of Quirk Synergy

by noctisxsol

In her search for the power to surpass All Might, Endeavor turned to a Quirk research lab. Little did she know that this would usher in the age of the Heroine and dating by statistics. What's a quirkless hero to do in a world like this? Make your Vows Izuku. Massive Gender-bends, Deku/harem.

4. Science Starts with Guessing

Issues of Quirk Compatibility

Chapter 4: Science Starts with People Guessing

"Speaking" "Thinking" [Sound effects] Quirk Names and Special Attacks

In her search for the power to surpass All Might, Endeavor turned to a Quirk research lab. Little did she know that this would usher in the age of the Heroine and dating by statistics. What's a quirkless hero to do in a world like this? Make your Vows Izuku; Massive Gender-bends, Deku/harem, Crack with Plot.

Izuku and his class are aged up by about four years. Need to get those hormones pumping at full and the advertisements to have time to convince nearly the whole country.

Anyway, the gist of this story is that Izuku makes his hero's journey in a world where almost all pro heroes are women, and he's a prime steak slathered in fan-service. Either that, or it's a deep and thoughtful examination of the objectification and empowerment of female super-heroes by the reversal of traditional gender roles. You'll see as it goes. Beware of Crack and other absurdities. But for now, On to the Story!

-The Endeavor Hero Agency: Ambition-

"As you can see in my report, there are multiple factors that we believe may be contributing to the Quirk evolution that occurred a few hours ago. The first and most likely in my opinion is the near-death experience, particularly the fear of imminent death. The fear of death would activate an adrenaline rush so powerful that it could possibly alter a person's quirk rapidly. The second factor is the suffocation, the lack of oxygen may have placed the brain in a more suggestible state that allowed it to evolve. Alternatively, the key may have come from the girl's boyfriend, primarily from the mental state that his singing invoked in her, likely combined with the prior conditions. Another possibility is that the young man himself was part of the key. He has phenomenally high synergy, which may have caused her quirk to resonate and evolve, or it may have something to do with his quirkless status. Miku thinks it's important that they were engaged and had intercourse recently; but I think that she's been going romance crazy ever since she caught Mei drooling over a picture of that green-haired idol fixing something shirtless."

Endeavor leafed through the file, stopping on a picture of Izuku. "I see. And why haven't you brought him here?"

"Because kidnapping is frowned upon? Because All Might took custody of him? Because his girlfriend is the one who had a quirk evolution and could very well be capable of leveling this entire complex if upset?"

Enjoli waved off her brother's concerns. "Unimportant. He may be the key to unlocking truly overwhelming power in my daughter, and is the perfect mate to produce an even stronger heir for my legacy to continue even further! If you will not take charge in this matter, then I shall! What's the number for his agency, I will purchase him!"

Enryo sighed, but gained a smirk as he came up with a comeback. "You really need to realize that everything doesn't revolve around you; I mean, your number two ranking should be proof enough of that."

As the man fled his sister's waves of fire, he let his mind wander over whether the boy would give him an autograph for effectively saving him from sexual slavery.

-Dagobah Junk Beach-

Izuku buried his head in his hands. Why did he do that? What made him think that trying to dominate Katsu would possibly turn out well? He winced as he felt the pain from one of his many bruises. "It turns out that being able to absorb the heat of fire doesn't do anything to protect you from the concussive force of an explosion. Where's my notebook? I should write this down for later."

"Would you say you learned to use protection next time?" Toshinori was enjoying the sight of his injured student far too much. "I imagine that rolling onto an antenna once was enough to teach you your lesson. And I'm sure your girlfriend will be a little more careful too, once the Coast Guard brings her back." Izuku groaned at the memory, but the withered hero ignored it. "Still, I'm proud of you. And not for the reason you may think! You displayed an impressive control over your power, especially for your first time! I knew I chose my successor well!"

The boy gave a nervous laugh as he remembered everything that happened in the last few hours. "Yeah, about that… Um, that wasn't All - I got a boost from - I don't technically, I mean, I didn't technically have a quirk before you gave me One for All, but I kind of did find a way to get something like a quirk." He raced ahead in his explanation when he saw his mentor about to interrupt. "It's the ability to absorb heat and use it as energy! I only got it when I went out to save Katsu from the slime villain! I knew I had to help her! I couldn't control my body!"

The skeletal man spewed blood in shock. "What!? You can do that!?" I mean, uh" He buffed himself up, the the blood dripping down his mouth ruined the image. "You acted like a true hero while many professionals just stood back. But if you're going to be my successor, I need to know everything you can do. So clench hard, fire up your power, and show me what you can do with your quirk at full blast!"

Izuku took a breath to calm down, and felt out the power resting inside of him. He could feel the dregs of fire still inside of him surrounding the shining core of energy that was his new quirk. He let it flow through his body and pool in his arm, shoulder, and leg. Unleashing his inner shounen action hero, he let loose a battle cry and cast out his fist… and near immediately regretted it when he felt his muscles protest.

All Might watched the wave of force tear across the ocean and winced when he heard Katsu's distant scream of frustration as she was blown further out to sea. "Well… We know you can use it at least… Provided you can survive what your girlfriend does when she gets back…"

Izuku gave a weak whimper. Whether from pain or fear, he still can't remember. "I think I dislocated my shoulder… and hyper-extended my elbow… and strained every muscle in my arm… I could do that again, but I really don't think I should…"

"Good job," The hero gave a hearty slap to the boy's back, but winced when he gave a sharp cry of pain. "Right, um, sorry about that! I'll get you to a doctor right away!"

-Next Day, Dagobah Beach-

"Did you seriously make a secret headquarters out of junk?" Izuku looked around the little alcove surrounded by trash and had to admit that it was a fairly nice place. A refurbished recliner and sofa provided seating, there was a small cooler filled with soda, a defunct camper and its awning provided shade and shelter, it was close enough to the shore that there wasn't any junk blocking the view of the sea, and it even had a small gas generator for some lights, a heater, and a minifridge.

A puff of smoke indicated that Toshinori had let himself relax with a cold soda in his hand. "I can't go all the time like I used to, so I made a bunch of little hide-outs where I could rest and recover. This was one of my favorites. It's too bad that I'm going to have to give it up." Pre-empting the question, he stood up and struck an explanation pose. "You see, this beach has for a long time been neglected and abused! What once was a beautiful public beach has now become nothing but a dump. To fix this Is The Job Of A HERO!" All Might stood for one second in his heroic pose, before blood spewed out of his mouth and ruined the image. "So you'll be cleaning up the beach. It'll be good exercise and public service, all in one! So let's start packing all this up!"

Holding in a sigh that the little lair had to be removed, Izuku didn't even think begore grabbing the still-running generator. When he felt the heat on his hands, he almost dropped it on instinct, but something stopped him. He could feel energy flowing into him from his hands. It only took a second to deduce what was happening, and it opened a very large realm of possibilities to him. "All Might! Turn on the lightbulb, I want to check something."

As Izuku held that bare bulb in his hands, he realized the true extent of his wish. He could absorb any kind of heat. The sources he could tap were almost limitless. He gained a smile as plans formed in his head. "I can do this. I will become a hero."

-Two Days Later, Midoriya Modeling-

Izuku took a deep breath to calm his nerves. It was rarely a good sign when a customer wanted to be present for a photo shoot. It generally meant that they were either a) incredibly picky and would find fault with every pose and scene and shot, b) a fan who wanted to be in the shoot themselves, no matter what modeling policy said, or c) a wealthy mother who would use the time to try and convince him to date her daughter.

And as it turned out, today's client was all three.

"How dare you refuse me! I didn't pay to watch a talentless photographer take pictures of my daughter's suitor! My Shojo should be up there posing with him!"

Masaru Bakugo bit back a retort and let Izuku answer. "You're paying for one of the greatest photographers in the modeling industry to take pictures of a registered model at the location and theme of your choosing. If you wanted your daughter to join the shoot, you needed to have the proper paperwork filed three days before the shoot. It was all detailed in the contract that was sent to you. You did read the contract, didn't you?"

Shojo felt a little smile creep onto her face as Endeavor seethed.

"Now listen here-" The Number Two hero began, but was swiftly cut off.

"No one is exempt from the rules. Not even you." Izuku sounded incredibly tired of dealing with objections like that.

"You only sent me the contract and forms two days ago!"

Masaru finally let himself speak in a clipped tone. "And you requested the shoot be as soon as possible. We're merely follow what you said you wanted. I'm sorry that the world doesn't conform to you every whim, Ms. Number Two Hero."

Endeavors flames burned brighter and it looked like there would be trouble when Shojo placed a hand on her arm. The intensity of the flames didn't decrease, but the woman's attention was gained. "Mother. I would like to learn how to model."

Flames spewed off the heroine as she shouted in utter excitement, "YYYYEEEESSSSS SHOJO! YOU HAVE BEGUN TO EMBRACE THE LEGACY YOU WERE BORN FOR! SOON YOU WILL UNLOCK THE SECRET YOU UNSTOPPABLE POWER!"

As Endeavor rambled on, Shojo felt her eyes get drawn in by the young green haired model. "I really like the way he smiles…" The girl was started out of her thoughts with a blush when her mother started to drag her away by the arm to "plan strategies." She still glanced back as often as she could, until the pair turned a corner.

Izuku let himself crumple to the ground and exhale the breath he was holding. Masaru let out a short laugh next to him. "Another day, another girl falls for Midoriya. Who would've thought Endeavor…"

-Todoroki Home-

Shojo stared at the blank piece of paper in front of her. Her mother had put the sheet of paper in front of her and said to make a plan to capture the green haired boy. While this was certainly preferable to the normal training, which bordered on abuse, she could at least figure out what she was supposed to be doing in that training. As it was, she was spending her time alternating between staring at the paper, staring at the wall, staring at the clock, and silently cursing that Endeavor had confiscated her phone to stop her from stealing strategies from the internet.

A muffled shout caught the girl's wandering attention. She strained her ears. It only took a moment to figure out that the sound was coming from the training hall.

Before the thought had fully formed, Shojo was already opening the door to the training room. She quickly wished that she hadn't.

Both of her parents lay on the floor, wrestling naked. Both of their hands were on the other's neck, and Shojo couldn't tell if they were trying to kill each other or were about the have sex. She wasn't sure which would be worse.

Endeavor seemed rather unphased at the whole situation, not bothering to cover up or even take her hands off of her husband's throat. "Ah, Shojo, good. Pay attention. Once you have properly attracted the attention of that boy, this is what you must do to continue the growth of your powers." Shojo noted that Reiji's face had turned blue before her mother slightly eased up to let him breathe.

The girl once again regretted opening the door as she came to the conclusion that it was in fact the worse option for her parents to be having sex. She closed the door and walked away, doing her best to repress the memory.

Endeavor glared at the barely conscious man beneath her as if everything was his fault. "You weak, useless, brainless, brainless poor excuse for a snowman! First you couldn't give me a strong heir, then you couldn't train her, then you couldn't help yourself but scar her, and now you can't even choke me properly! I told you to choke me, not just rub my neck! I need that power! I won't let some lucky slip of a girl overshadow me; I'll figure out what caused that evolution and finally gain the power to defeat All Might!"

Reiji had no answer, and once again regretted marrying this woman.

-Mighty Agency-

Izuku stared at the small industrial laser that had been set up in one of the training rooms. The machine wasn't anything special, it was downright pedestrian in a world of quirks, but that laser seemed like the whole world to Izuku for almost a minute.

"This is the moment of truth. If this works out the way I think it will, then the vow really is something that will change the world! Everyone who's quirkless can get powers now!" Katsu's face flashed in his mind, and he grimaced at the reminder of the associated cost and risks. "No, I can't let anyone else know. It was stupid and risky, I shouldn't have done it in the first place. Did I even think ahead at all? Ten bowls of incense per week? What am I supposed to do if one of us gets sick or hurt? Am I just supposed to light the incense in the hospital? And I can't just ignore Katsu, but people are going to start rumors if anyone catches us while fulfilling the vow! They'll think we're about to have s-s-s"

"Starting up the laser!" The bubbly intern was too caught up in her own world to care about Izuku's mutterings or the proper safety procedures, and instead started the machine at full power.

The beam of light burned through a sheet of metal and was shining on Izuku before the boy had a chance to move more than an inch. To the joy of a great many fangirls, it ignited the boy's shirt.

On instinct, Izuku tore off the flaming piece of clothing before remembering that he was fireproof. Even more fortunately for his fangirls, the chiseled muscles that were revealed were completely unmarred by the powerful beam.

A smile bloomed on the boy's face and his eyes shone with tears of joy. He felt the energy from the heat flowing into him, and for the first time he actually believed that he could be a real hero. His joy wasn't even diminished when he heard the telltale crashing of Katsu's arrival. This would be the first time he saw her since accidentally sending her off to sea.

The girl was visibly furious. Explosions and tongues of flames emerged at random. She was even sporting flaming wing and a tail, but the words that came out of her mouth were purely Katsu. "Deku! You… What the fuck has you so happy?"

"You…" Whatever else Izuku was going to say was lost in a sea of presuppositions and raging emotions. Katsu pulled him into a searing kiss, whispering that she accepted the accepting the assumed apology and glaring at the giggling intern. When she finally allowed him to pull away, he had a determined glint in his eye. "Katsu… come with me. I need to do something with you."

The girl couldn't push him fast enough.

-Midoriya Estate Gardens-

Izuku had never felt so awkward since the first time he had to perform for a concert in nothing but a speedo and body paint. Katsu would have been dragging him, if she knew where they were going, so instead she occupied herself by growling at any girl that dared to look at him. It certainly didn't help matters that she refused to let him take the time to grab another shirt, and she herself was attracting attention with her temporary demonic features.

It was almost a relief when they made it into the relative privacy of the shared estate that Izuku had inherited from a fan. The older man was going to give his whole estate for hero training, but decided to give half to Izuku after the boy became well known for striving to be the first quirkless hero. Inko had insisted that the Bakugos move into the estate as well, since "They're basically family already, and it'll only be a few years before Izu and Katsu start dating!"

As much as Izuku loved his mother, he still had to admit that she went a little crazy when it came to him making a family. He breathed a heavy sigh of relief when he saw their two mothers taking tea together in one of the rooms. That meant that he could slip into his room unnoticed to grab the incense before leading Katsu into a grove in the garden.

Izuku got to work setting up the bowls of incense, and held out a hand to invite Katsu into the circle with him. Or rather, he was in the middle of doing that when he froze. Why did he freeze? He realized the girl's current state of dress, or rather, undress. The only covering that the transformed woman had left were the two silver rings that Efreet wore, and those even had been shifted to cover nothing.

Katsu drank in the idol's frozen expression with hidden glee. Watching the awe and arousal slowly flood his face lit a blazing fire in her that compelled her to act. She traced a finger down his arm. "You went through all this work…" Her finger continued to trace the muscles on his chest. "…They say you always remember your first, but I'll always be glad to remind you if you need it." Her tongue teased his ear, before she went in for a nibble on the lobe. "There's just one problem…" Her other hand went down to cup the obvious bulge in his pants. "…You're still over-dressed." She reveled her dominance, but something in the fire seemed to stop her from doing more than teasing without his permission.

But that permission wasn't coming. Izuku was seemingly having a mental meltdown, he wasn't going to be saying anything coherent any time soon at this rate.

Katsu continued following the directions of the fire, but it wasn't enough for her. She needed more, and apparently Izuku had to be the one to go further. Finally she snapped. "Damnit Deku! Fucking Strip and smash me!"

The shout pulled the shy boy back to reality. With a blush and a shout he pushed her away and fell to the ground. Frantically he waved his arms at her in a vague attempt at explanation. "Katsu, No, I, Um… I read in a book that doing this would help with your quirk!"

The transformation slowly faded as both anger and lust slowly ebbed away in the face of what seemed to be an honest attempt to help her. "Fine! But you still have to make it up to me for getting my hopes up."

Katsu plopped herself down in the middle of the circle with a pout, and Efreet soon followed suit. Izuku carefully lit the incense, before joining them in the circle. He sat down pressing his back against the girl, and tried to calm down. After a few breaths he felt the aroma seep into his nerves and start their work. After a minute of awkward silence, he finally spoke. "This is nice, isn't it?"

When he didn't receive a response, he glanced back and saw Katsu already nodding off. After a huge yawn she finally spoke. "Catch me…"

Izuku barely had any time before her head dropped onto his lap. He looked around to make sure that no one was watching, before gently brushing a strand of hair of her face. "It must be really exhausting exploding all the time…" Katsu didn't say anything, her breathing light and even. "But you know, I think you're really beautiful when you're sleeping…"

Unseen, a smile bloomed on the girls face. "Maybe Hot Wings isn't so bad after all… I wouldn't mind doing this every week. and I'm sure my Deku won't mind if my hands wander a bit. Who knows what my hands might do while I'm asleep."

-Chapter 4 End-

This chapter took a while to write, but I hope you enjoy it. Get an introduction to Shojo Todoroki, some power progression for Izuku, and some actually romantic scenes with Katsu! What is this madness? Actual, non-sexual romance is my harem comedy? Heresy! Heresy!

Don't worry, I'll make it up to you with an Omake

-Omake, Endeavor's Married Life-

Enjoli Todoroki stormed into Quirk Research Labs on the second day of her honeymoon. Without even her usual preamble, she launched into a rant. "Marriage is the worst idea ever! He can't cook, doesn't clean, and has terrible taste! Worst of all, he's as cold as a block of ice!"

Enryo looked by from his microscope with a smile that declared "I told you so." "Well, you did effectively buy him from his family, it's no surprise if he isn't eager to be lovey-dovey with you. Plus, I'm pretty sure that the collar and blinders helped matters any."

The woman waved off his remarks. "I don't care how he acts, and those were necessary to keep him in line. The problem is that he is literally cold. His feet feel like ice, and the two minutes it took him to finish inside were the worst of my life."

The man already had a note pad ready for his sisters demands. "Let me guess; you want something to raise his body temperature, and increase his longevity?" He already had a bottle in hand ready for her.

Endeavor scoffed. "Of course not, those would be a waste of resources. I want something that will make him finish faster so I can send him back to his room sooner."

Enryo stared at his sister as he slowly set down the supplements he used to keep up with Miku's demands. "Somedays Joli, Somedays you leave me utterly shocked at how much of an asshole you are."

The Heroine flipped her ponytail in dismissal. "Fine, If you won't help, then I will send my husband to figure it out on his own. But I'm telling Miku that you aren't allowed to have another child until I'm pregnant."

Enryo truly did wonder if his sister even realized that giving out punishments like that is what made him so willing to oppose her.