Chapter Text
An AU where Izuku is a mer, and AFO is a very rich CEO who owns the country's largest aquarium and marine rescue centre. Except that AFO does dirty deals under the table, secretly selling animals to whoever has the money and wants to buy (generally situations like other rich ppl wanting to buy their kid their own dolphin or whatever).
Merfolk are largely thought to be a myth among the common people, but the elite of society know they exist. And the real reason AFO became so rich and powerful? He is one of the only suppliers for merfolk out there. His company researches and captures merfolk........and he's willing to sell them to the highest bidder as well. All out of the public eye of course.
And then one day Izuku is one of the mers captured and brought back to the facility. A young mer on the verge of death due to an attack that killed his parents and has heavily injured him.
AFO normally doesn't get attached to the mers, but this one is a bit different. Perhaps it's the way the young mer kind of reminds him of his own son that passed away years ago. Perhaps it's just because this mer is the first child of its kind to be captured and brought in, and he's curious about this new development.
Whatever the reason, AFO decides to keep this mer for himself, taking Izuku to his own home.
Izuku is not having a good time. He's hurt. His parents just died. And now he's trapped in a (admittedly large and nice) aquarium in some random human's house. And he can't even understand what's happening to him because he can't speak any human languages.
RIP to him.
At least Izu doesn't have to go through any extreme experiments. Just blood samples and monitoring and whatnot.
Other mers?.....and humans?
In this AU mers dont have the ability to gain legs. And AFO is spearheading an experiment, trying to see if he can turn mers into humans and give them legs—as well as take unwilling human subjects and attempt to turn them into mers. He's interested to see if he can create a hybrid or a way to transform back and forth.
It’s a horrifying experiment. He cuts off legs and tails and attempts to surgically alter both the humans and mers to become the opposite species. He attempts to combine blood and DNA and create something new or inject a cocktail of it into a subject and see what happens.
Izuku doesn't see any of this but that's what happens behind the scenes. He easily grows attached to AFO because he's like 10 years old and desperate and scared. And as time goes on AFO becomes more endeared to Izuku as well and does eventually become somewhat of a decent father to Izuku and actually care about him.
Hisashi tipped the small aquarium over into the huge glass tank he had installed in the floor of one of the many living rooms in his mansion. The small merboy inside tumbled out of the travelling container, splashing into the waters below with disoriented flailing. Hisashi observed him curiously, watching as the young mer began to swim around frantically—or as best as he could with his injuries anyway. The poor thing kept bashing himself into the glass walls, unused to being anywhere other then open waters.
The giant tank was mostly empty for now; Hisashi would fill it with appropriate environmental enrichment once the merboy was more recovered. It was easier to keep an eye on him this way, with nothing for him to hide behind or seclude himself in.
As Hisashi watched, the boy's frenzied attempts to find a way out began to slow, whether because of exhaustion or acceptance he didn't know. But the little mer eventually sunk down to the sandy floor of the tank, curling in on himself and fanning his fins out to hide his face.
Hisashi wasn't really sure where to go from there. As much as merfolk were a big part of his business, he didn't personally interact with them much beyond occasionally taking a more hands-on role in the experiments he ran. He sighed and ran a hand through his hair.
He supposed he should give the child a name at least.
Hisashi released a clicking trill from his throat, one of the few sounds he had managed to learn from merfolk language. As far as they had been able to tell, this one was simply a call to attention, a "come here" of sorts. Study of the mer's language was still ongoing, but many of the sounds they made could not be easily replicate by humans, which made the language quite difficult to parse out. So if Hisashi wanted to communicate with the new merchild he had impulsively brought home, he would have to teach it his language.
The call worked well enough however, and the little merboy perked up and swam to the surface curiously, keeping a cautious distance away from Hisashi. The boy said something back in that trilling tongue of his, and Hisashi frowned and crooked a finger at the child, repeating the call for him to come over.
It took a few minutes of coaxing (Hisashi pushing down any signs of irritation so as not to scare the child off) but eventually curiosity won out and the merboy swam close. Hisashi was seated on the sloping wooden deck he had installed around the perimeter of the tank, and once the boy was within reach he grabbed the child and pulled him up on the deck beside him.
The boy screeched at his touch, wiggling viciously to try and get away, small claws snagging in Hisashi's suit as he flailed in panic. Hisashi grabbed his tiny wrists tightly, irritation rising to the surface. "Enough!" he shouted in the mer's face.
The boy immediately burst into tears, ceasing his struggles as heavy sobs racked his little body.
Hisashi ground his palms into his eyes and groaned. Fantastic. 'Well done', he thought to himself, 'you've succeeded in making an already traumatized ten year old cry. What were you expecting?'
He sighed heavily and forced himself to calm down, turning his attention back to the merboy who was still crying his little heart out. "Come now," Hisashi said, pitching his voice low and soothing. "You've had such a stressful day, haven't you? Everything is fine now, no need for more tears." The mer couldn't understand him, but surely his tone of voice would convey enough to the child to help him calm down.
Slowly, he reached out and touched the boy's arm. The mer flinched but didn't react beyond that, still crying into his hands. Hisashi then reached out with his other hand, wrapping them around the boy's arms and pulling him closer so that they were side by side. The child peeked up at him then from between his webbed fingers, face blotchy with tears. Hisashi felt an ugly twist in his heart as he was reminded of his own son who had looked at him the same way whenever he got hurt, wanting Hisashi to hold him and kiss his bruises and scrapes away.
Caught in the unexpected memory, he was taken off guard when the merchild in front of him let out a loud hiccuping sob and lunged forward to wrap his little arms around Hisashi's neck, burying his face into the man's chest.
Hisashi sat stunned, eyes wide and mouth agape as his suit dampened from the boy's wet skin and tears. Hesitantly, he wrapped his own arms around the boy in return, awkwardly patting his back and shushing him. The child responded positively to the comforting physical contact, so Hisashi kept it up, closing his eyes and imagining his son as he rocked the merboy gently, holding him close until his cries died down into small sniffles.
It wasn't hard to think of a name after that. Hisashi was torn about it, feeling somewhat guilty giving away that name to anyone else, but...
He lifted the child's chin up to look at him properly, the merboy holding his gaze with childish curiosity.
He didn't look like Hisashi's deceased son. The mer's hair and eyes were green where his son had inherited his colouring. But the round cheeks, the button nose, the wide eyes, and the innocence found in the mer's face? Those reminded him so much of his own child.
It was decided then.
"Izuku," Hisashi told the little mer, who only tilted his head in confusion. "Your name will be Izuku."
Hisashi couldn't sleep. Despite how large his mansion was, that shrill voice echoed everywhere. He'd been lying in bed and trying to ignore it for the last hour or so, but it was really starting to get on his nerves.
A pause.
He held his breath...silence. Hisashi sighed in relief and closed his eyes.
Only to snap them back open when another, higher pitched scream broke the night.
Hisashi growled angrily and threw himself out of bed, stomping through his house to the living room where the tank built into the floor resided. The lights turned on ahead of him automatically, state of the art sensors that left no need for switches.
He entered the living room to be greeted by the sight of the small merboy halfway across the floor, face red from crying and arm outstretched to Hisashi as soon as he saw him. Hisashi pinched his nose and exhaled loudly, bemoaning the water Izuku had trailed behind him when pulling himself out of his tank.
The mer trilled something in his native tongue, sounding sorrowful. Hisashi rubbed his eyes and took a moment to assess the situation.
Ok. So. A young child who just watched his parents die and was captured from his home right after. In a dark room and an empty tank. Alone and likely in pain from his own injuries from the attack.
...He could see the problem.
Another heavy sigh and Hisashi stepped forward, almost tripping when the boy immediately clung to his legs. "Izuku, please," he admonished, leaning down to lift Izuku into his arms, the little mer happily switching his grip from Hisashi's legs to his neck.
He carried Izuku back to the tank, and attempted to drop the boy back into the water.
…Except he wouldn't let go.
"Izuku, PLEASE," Hisashi repeated, trying to pry the child off of him. Izuku's tail thrashed about, his little arms clinging tightly to his neck as he made a few desperate sounding clicks in his throat.
Hisashi sat down on the deck, continuing to wrestle with Izuku to release him. "Let go, you're going to have to get used to this, Izuku." Eventually the boy would grow accustom to his new living arrangements—something Hisashi hoped would happen quickly.
Despite being very tenacious, Hisashi was still much stronger than the little mer, and eventually succeeded in prying Izuku off of himself, pushing the boy back into his tank. He stood and backed away quickly when Izuku swam back to the edge and lunged for his ankle. "That's enough, Izuku!" he snapped, some of his anger leaking into his voice. "Quiet down and go to sleep, I don't want to hear anymore screaming."
Hisashi turned to leave, but a wretched wail made him pause. Izuku had once again pulled himself up onto the deck, his face twisted with fear and panic, reaching out for Hisashi. Hisashi tugged on his hair and growled to himself. It was late, he was tired, and he had had enough. "Fine," he huffed, "you win for tonight."
He stormed out to the nearest bedroom, ripping the blankets and pillows off the bed and making his way back to where Izuku was once again screaming. "Please shut up," he begged the merboy. He dumped the bedding onto one of the couches nearby before pulling the couch closer to the tank. Hisashi then flopped down on it, exhausted but grateful when Izuku went quiet. Only small hiccups and sniffles came from the boy now, interspersed with the low trills and coos of whatever he was saying in his own language.
Hisashi clapped his hands and the lights in the room dimmed. "Go to sleep," he command Izuku, closing his eyes and rolling onto his side.
It didn't take long for Hisashi to drift off, and he was almost fully asleep when a small hand patted his shoulder almost curiously, the couch dipping under him. Hisashi's eyes snapped back open to find Izuku right in front of him, the child attempting to pull himself up on the couch beside Hisashi. "Izuku. No. Go back to your tank." He pushed the child off, Izuku falling to the ground and looking up at him with hurt. "You have to stay in the water," he explained. “I'll be right here the whole night, ok? You can't stay here with me, you need to remain in the water.”
That wasn't fully true of course, Hisashi's research and experiments on merfolk had shown that mers could stay out of water for long periods of time without any severe adverse effects. That was a good sign, it meant that merfolk likely could survive on land as humans do, he just had to successfully give one legs to find out for sure.
...Izuku was trying to crawl up on the couch again. "No, Izuku," Hisashi scolded. "You're all wet. Stay down." The child was nothing if not persistent however, letting out little cries and whimpers every time Hisashi rejected him, but still coming back to try again.
Eventually, Hisashi gave up. Izuku was more or less dry at this point with how long he had been at it and Hisashi was much too tired to care anymore. The next time Izuku tried, Hisashi reached down and heaved the little mer up next to him, scooting back to make more room for Izuku on the couch. Izuku trilled contentedly, burrowing into Hisashi with no concept or care for personal space.
Hisashi simply resigned himself to his fate for the night and arranged the blankets over Izuku, allowing his arm to remain wrapped around his child's waist.