Work Text:
Izuku scratched his stomach, as he got up a bit earlier than usual. For some reason his doorbell had rung, but after a minute it seemed to be silent. He hadn’t rushed himself, but still got up, put on pants and headed to the door. Yawning, Izuku opened the door, just to stare at emptiness. He furrowed his eyebrows and looked around a bit, he didn’t see anyone disappear into the other apartments nor did he see anyone at the stairs. He shrugged and happened to look down, to finally notice a package at the side. It was against the wall and realization hit him. Of course it had been the postal worker, they usually didn’t want him to sign anything anymore. It was probably the one of the many things he had ordered recently.
Izuku hummed while he walked back into his apartment with the package in hand. Another yawn escaped his lips, which made him just put the package on the table while he made coffee. He really needed it and since he was already up, might as well start the day. He didn’t need to leave for work yet, so slow morning, maybe go for a run and then shower. That sounded like a good order of things Izuku thought for himself as he loaded the coffee machine and started it. The relaxing and familiar sounds of the machine, accompanied with the smell that hit almost instantly always made him more awake than anything else.
Izuku soon moved the chair a bit and sat down on his usual spot. The package couldn’t wait any longer so Izuku grabbed and pulled it closer to himself. The strip was ripped off easily and thrown to the side as Izuku already eagerly peaked inside. His other brow raised as he took the stuff in, removing a few pieces of packing material. Bottle of Methylene Blue, some melafix, bandages and antibiotics. He surely hadn’t ordered any of these. He didn’t have fish and all that he ordered into the clinic never came to his address, not even by a mistake. Izuku closed the box, looking closer at the slip. Oh. It was for his neighbor Mr. Todoroki. He hadn’t known that the man had any fish, but with an order like this it was clear that the fish was injured. Some stuff in the box was totally weird though and not something the man would need.
At that moment Izuku decided he would drink the coffee, put on running clothes and go deliver the package to his neighbor before he went. Maybe he could give a few tips. Just out of concern.
Not even half an hour later Izuku was knocking on the door. It had been a while since he had talked to his neighbor after all. Mr. Todoroki didn’t talk much and usually just wanted to greet and not much else. He did know the man worked at a law firm and had a husky boy named Soba. Which apparently had heard the knock first and was now barking at the door a few times before Izuku heard a voice inside. Phew, it seemed like he was home.
"Oh, Mr. Midoriya, good morning," said the man opening the door. Todoroki was a bit taller than him, white and red hair, already dressed in a suit and tie at this early hour.
"Ah, good morning Todoroki-san," Izuku bowed, "I accidentally opened your package as it was mistakenly left at my door. Apologies."
"Ahh, right. Don’t worry about it, it happens," Todoroki answered as he grabbed the already opened package. Izuku was clearly widgeting, as was Soba, who was whining behind his owner.
"I… Um, sorry if this is me intruding, but," Izuku let out, lowering his gaze a bit, before he dared to look at the man again. "I saw what you got. Do you have fish? Are they injured? You really shouldn’t use bandage…"
"Oh!" Todoroki exclaimed, "right, you’re a vet. I didn’t even think about that last night. That’s totally on me. And I just googled and someone said to get bandages so I did."
Izuku lifted his brow a bit confused. Still no answer to the other question, but it was fine. "Uh, yea I am. So what happened last night? Did the other fish attack them?" At this point he just assumed there was a hurt fish. And if there was conflict, getting the fish to its own space was critical.
"Oh, I don’t really know the details. He refuses to talk," Todoroki said, taking a quick look at the watch in his hand. "In fact I really don’t know much about fish. Would you mind helping for a bit? I don’t want to be late for work."
Izuku frowned while listening to Todoroki’s words. The man always was a bit of a mystery to him, but he never spoke nonsense. Maybe this was just one of his usual sayings that he just didn’t happen to understand. "Oh, okay. I have time before I have to be at the clinic," Izuku agreed. He could skip the run, or go for a way shorter one. At this point he was a bit concerned for the poor fish.
"So, how long have you had fish then?" Izuku asked as he stepped in and started petting the dog that came to happily greet him.
"Since last night."
Izuku opened his mouth for more questions, but he decided that right now he just didn’t want to do that. Instead he just removed his shoes and stepped further into the apartment, following Todoroki to the bathroom.
At the door Izuku halted, "I-I’m sorry, I didn’t realize I shouldn’t follow you here." He said abruptly, raising his other arm in front of his eyes as he took a few steps back. He really didn’t plan to interrupt someone's bathtime and obviously the fish tank would not be in the bathroom. He had just blindly followed the man not realizing there was also someone else in the house.
"Huh? No. Please come inside." As Todoroki had finished his sentence, Izuku heard a loud splash and could hear water hitting the floor. All the while Todoroki sighed, "he’s a bit shy I suppose."
Shy? The guy? Izuku was ready to walk out. This was the weirdest situation ever. Was he invited to some weird threesome he didn’t know about? Was that what Todoroki had tried to say?
"T-Todoroki-san, I really don’t… Um, I just came to see the fish."
"Shouto. And yes, the fish. Come inside."
Izuku was still so confused about the whole situation, but slowly he lowered the arm in front of his eyes and took a step forward, back into the bathroom. He first looked at Shouto, who nodded to the bathtub. Izuku gulped, slowly starting to turn his head to the direction. And holy shit. There was no human face right now, but he could clearly see a figure under the water. And that huge, clearly scaled tail coming from the water, over the edge of the bathtub and into the floor. The color was dark, almost black, but the parts light hit almost seemed green. There were also a few orange scales here and there, making mesmerizing patterns around the tail.
"Wow," it was all Izuku could get out of his head, before his mind started to race. He could see that part, also the huge wound alongside the tail. It looked like a fin had ripped and a large portion of the scales had gone with it. It looked painful. This time Izuku really frowned. He was excited, but all the worry started to pile up almost instantly. Fascination about this clearly mythical creature had to wait for now.
"I think we should at least get the tail into the water. And maybe change the water for now," Izuku murmured, trying to look at the logistics of the small bathtub. The tail should fit, but the other part of the creature might not. Also could he really use the same antibiotics on this creature than for a fish? Or should he get some that are for humans? At least he needed a higher dose than what Todoroki had bought.
"Oh, the package, can you hand the blue liquid?" Izuku asked in between his mumbling, speaking louder. Thankfully Shouto clearly listened and after some obvious package opening Izuku was handed a bottle. At this point he was a bit lost. Fish usually just needed time with their wounds, maybe antibiotics, sometimes some salt to the water and a lot of the times methylene blue products helped. But this wasn’t just a fish.
Izuku dropped down on his knees beside the bathtub. The floor was wet there, but it didn’t really matter. He tried to peek into the water just to see the creature better. The top half was clearly human. Sure, he had black finns in his head, in his back and some on the arms and hips, even scales here and there. But it was human, with a stomach, chest, hands, neck, head and even hair.
"Hey. Shouto said you haven’t talked, but. I’d like to treat your wounds and you must know that dry air isn’t doing you any favors right now," Izuku said, trying to sound as calm as possible. He waited patiently, but clearly the creature didn’t want to come up nor answer him.
Izuku turned his head to face Shouto, "so how do you have… This? That? Them?"
"Well I was on my way home last night and I walked by the sea, and saw this huge thing on the shore. So logically I carried it home. Put it in the water and I’ve been trying to talk to it. Ordered stuff late at night as speed delivery."
"Huh? That’s it? You carried this? From the sea to here?" Sure the apartment wasn’t far from the sea, but he couldn’t imagine it at all. And no one had stopped him? Seeing the sight would’ve stopped anyone at their tracks for sure.
"Yes. I thought about calling somewhere, but it was late."
Izuku took the answer. It wasn’t like he was going to get anything better for now it seemed. And not calling the emergency line seemed like the right call. A creature like this in the hands of the public seemed wrong to him.
"So, you might not speak Japanese at all. But we’d really need to get your tail into the water, okay?" Izuku tried to use his hands, point the tail, show a lift, try to imitate the splash and the tub somehow. He didn’t really know what he was supposed to do.
Sadly there seemed to be no answer which made Izuku sigh. He looked at Shouto, "do you think we could try and lift it?"
"Sure with the two of us. He might trash a bit though, hit me pretty hard earlier," Shouto admitted.
After that they both moved to the tail, Izuku trying first with a very slight touch. The scales were clearly drying up from just the air and the little water that had been on them when he got here was clearly all gone. The tail moved a bit, but that made Izuku just nod to Shouto and both of them grabbed the tail with both hands. This made the creature move, the massive tail trying to get out of their grasps.
It took a lot of effort, but it was clear at the end that the wound didn’t make it easy for the creature to use its body fully. With them pushing the tail to the water the top half of the creature emerged from the water and the expression was not pleased at all. Looked like they were scowling.
"I’m so sorry we had to do this. But the wound needs water, would you like salt in?" Izuku tried to ask, keeping his eyes on the creature's eyes he could now see for the first time clearly. Striking red, looking straight through him. "Souto, we need to change the water, where is the plug? Can you turn on the water after I get it?"
"It’s at the end, probably under the tail now. Good luck."
Izuku grimaced, "Okay. Don’t freak out. I’m going to get the plug so we can change the water okay?"
No answer, not a change of expression, nothing. Izuku had to snap his eyes off the creature so he could focus on the task. He stooped down, getting his hands into the water. This clearly wasn’t the thing the creature wanted and Izuku could feel a scaly, rough hand on his wrist. A claw was pushing into his skin which made Izuku yelp. The creature let go instantly, which made Izuku just lift his hands out of the water. He quickly grabbed his wrist with the other, eyes all apologetic towards the creature, "I really am sorry," Izuku turned his head towards Souto, "just run the water. I’ll try to make sure most of it gets replaced and I stay here a bit and clean."
"Alright. I really need to get to work. Lock the door once you leave. If you have a free day feel free to stay. Or if you have work, do come back later. I’m only working normal office hours today. Also don’t let Soba into the bathroom," Souto said without much fanfare. Izuku was always amazed by this man whose expression just didn’t seem to change ever. What would he look like, sad, mad or happy? Izuku couldn’t picture it.
"Thank you. I do have work, I’ll see about it later," Izuku said, nodding after Shouto began to leave the bathroom. His gaze went back to the creature in the tub. They weren’t looking at him anymore, but clearly pouting at the water pouring into the tub and overflowing. The sight made Izuku chuckle softly, "what a weird creature. And what should I even call you?" It came as no surprise that there was no answer to his question.
–
The water had mostly replaced itself so Izuku had shut down the flow and was pouring the methylene into the water. He could hear some kind of hiss from the creature and Izuku tried his best to look reassuring by smiling.
"Don’t worry. This will help. But I need to do this for a few days okay?" Izuku tried to look at those striking red eyes for answers, but he didn’t get any. Izuku checked his phone for time and muttered to himself. He had to go and change clothes soon and then leave for work. He hadn’t even prepared his lunch so he would just have to buy something. Would the creature be okay for the whole day alone? And had Shouto fed them at all? Izuku lifted his gaze back to the creature slowly.
"Are you hungry?" Izuku tried, lifting his eyebrows slightly. He soon said the words again while trying to imitate eating with his hands and mouth. Once again he got nothing. "Okay. I have to leave. I hope you don’t just jump out on your own. And keep the tail in the water or the treatment won’t help." Izuku spoke as he was getting up fully, gazing at the creature. It sure was beautiful. All of those colors, even the human parts, were stunning. It was hard to avert the gaze from those toned abs, those eyes or the strikingly beautiful tail. He needed to do some research for this. He had never seen a creature like this and there was no way he was going to report it. At least not yet.
"See you later," Izuku said as he walked out of the bathroom a bit hesitant. He felt bad leaving, but he had his own little patients waiting. This creature could easily wait for the day, right?
–
In the end Izuku hadn’t managed to stay at work for more than for a few early appointments. He had promised to stay on call for the rest of the day. He had tried his best to research the creature, finding nothing else, but myths and legends. By this point he concluded at least that he could call the creature something akin to a Merman. Izuku had contacted Shouto for a key, before hitting the grocery store. He had gotten mainly seafood and a few other things. He couldn’t imagine someone living under the sea to eat something else than seaweeds, fish or other things you could find out there.
Izuku had also grabbed some more supplies from home, before he opened the door to Shouto’s place again. He had been gone for around five hours, and Soba at least was very excited to see him. Izuku took off his shoes before venturing further into the apartment. The bathroom door was still closed which he took as a good sign. Maybe he should’ve changed his clothes from the work ones, but he could wash them later.
"Hi, I’m back," Izuku exclaimed as he opened the bathroom door again. He could hear the water splashing a little and when he got in he could see the piercing gaze on him again. "U-uh, I brought some food. I didn’t know what you eat, so I bought a bit of everything," Izuku said while setting down all of the things. He really hoped the Merman liked something he got so he could later just go buy some more of that.
"So I think the hours have been enough, I’d need to filter the water to a new one again. So sorry that I have to do this again," Izuku explained as he was trying to explain again with his hands. He really looked sorry, as he moved to the tap and let the water run again. Slight hiss and the creature turned away from him. Izuku shook his head a bit before settling a bit further to wait for the water to just flow over the tub. Maybe tomorrow he could try to take the plug out again.
"Okay. I think it’s clear again. Would you… Like salt?" Izuku asked cautiously while shutting the water. He didn’t get any aquarium specific salts, but normal salt should do the trick. And he got a few big bags, just in case. Though once again he got no answer. Instead he noticed that the creature's nose was twitching a bit. At that point Izuku remembered that he had all the food at his feet. "Oh, right, I’m so sorry," Izuku yelped, picking up the first bag. It had fresh fish in it, which he had thought would most likely do the trick. He reached into the bag, seeing the Mer coming a bit closer curiously when one wrapped package emerged from the plastic bag.
"I hope this is something you’d take. Sadly all the fish had been gutted, but I’ll try to look at other places if…" Izuku rambled on about the fish while unwrapping the package. He hadn’t even realized how close the creature had gotten to him at that point. Izuku almost jumped once he lifted his gaze. The red eyes were eyeing the fish and the nose was clearly picking up the smell. "It’s okay, you can take it. Here," Izuku said while slowly offering the big Salmon to the Mer. The creature lifted its gaze for a second to look at him, before it finally grabbed the fish with one quick movement.
Seeing the creature start eating with a clear appetite made Izuku sigh in relief. Sure it was a bit of a weird sight, the Mer just had a grip on both ends of the fish and ate from the middle. But it was eating. "Okay, so you like fish. That’s good, okay. I should take notes," Izuku mumbled, putting the bag down to pick one of his emptier notebooks from his backpack. He could dedicate one to this creature. While observing the Mer Izuku wrote down everything he had seen and learned so far today. The creature was mysterious and beautiful, clearly at some parts wild and Izuku just wondered so much. He just wished the thing could talk, or that it would at least give out some sign that it understood.
"Oi, shut up. Ruinin’ my fucking dinner."
The sound made Izuku drop his pen as his head snapped up from the notebook. Had the creature just spoken? So they could actually speak Japanese? Izuku was baffled, and he could feel how his already high amount of interest towards the creature rose even more. He was practically buzzing with enthusiasm. He didn’t care at all about the fact that he had clearly been mumbling again.
"Tch, quit staring," the creature said between bites and glared at him, eyebrows furrowed angrily. Izuku shut his gaping mouth and moved his gaze down back to his notebook. He wrote down this new information fast. He wanted to ask so many questions, but he reckoned it would probably be best to give the Mer time to eat in peace. Izuku kept writing into his notebook while trying not to stare at the Mer and he did his best not to mumble either.
Soon Izuku could just feel the stare that was fully on him again. He did not dare to lift his gaze for a bit. Somehow the Mer got even more intimidating with their stares and attitude now that they had talked. Suddenly the whole situation felt more weird than before, like he actually had a person in a bathtub at his neighbor's house.
Gulping Izuku finally lifted his head up to look at the creature when he was sure he had written everything he knew so far. Oh God. That really wasn’t just a wild, innocent animal.
"Um, would you… Would you let me take a look at your injury?" Izuku tried, hopeful. But the Mer seemed to just scoff and say nothing. Okay. Maybe that was still too much to ask. And Izuku knew he really couldn’t do that much to help at this point. "The damage seemed like a lot, I mean… You seemed to miss a fin. I think…" Izuku suddenly felt shy as the gaze had turned back to him, sharp and piercing through. "uh… S-some antibiotics would really benefit you."
"What the shit is an antibiotic?"
Izuku was overjoyed that the Mer seemed to answer him again. So he might just have to talk enough and he might get an answer here and there. "It’s a medicine. It should prevent infection, I mean, I’d imagine you’d like to return to the sea and… Infections can get really serious."
"Tch, human stuff is useless. The blue shit did nothing."
"Ah! It will speed the process, you’ll see after a few days I promise," Izuku exclaimed. He really wanted the creature to have a positive mind. He really wanted to help and it would be many times better if the Mer agreed to the care. Izuku really didn’t want to do anything that the other didn’t want.
"Fine. If it smells funny I ain’t taking it."
Izuku perked up more and moved to his bags. He should take the rest of the food into the kitchen, but he was way too excited right now to do so. Izuku grabbed the medicine, taking one pill out. Twice a day should be fine, the area of injury was quite big though so he anticipated it was better to keep up with this for at least five days.
"Here. You just swallow it." The Mer didn’t take it, instead he moved closer to the edge of the tub and put his face close to Izukus hand. He sniffed the tiny pill for a bit, before he leaned even closer and licked it fast. The Mer shivered and scoffed.
"Tastes like fucking lionfish. You trying to poison me?"
"N-no, of course not. Most human medicine tastes bad," Izuku explained. This didn’t seem to make the Mer any less suspicious. "How do I convince you? I guess I could… Take one. Or," Izuku really tried to think. It shouldn’t be harmful to take one, and he really wanted the creature to start the course. He would hate it if this all ended with a bad infection.
"... Fine. Just quit it. You’re fucking mumbling again. It’s annoying," the Mer scowled before lunging at Izuku's hand and just chomped on the pill. The feel of those lips and fangs grazing his hand made a shiver run down Izuku's spine. He had touched the tail before, but now he was imagining what it would like to actually touch the Mer better. He was very curious, more and more after each second.
"Thank you, you did good. I’ll make sure Shouto keeps giving these to you," Izuku smiled widely. His words seemed to make the Mers face grow a bit red, but also made his brows grow more angry.
"I’m not taking shit from that damned sea slug."
"O-oh. But I have to go back home and, he lives here and-"
"Not my problem."
Izuku felt a bit speechless. He couldn’t really just come to Shoutos apartment everytime the Mer would need anything, be it food or water change. But the damn eyes were looking at him so seriously with the clear no to any other options.
"If…" Izuku inhaled, "if you won’t let Shouto take care of you then I’m going to need you to cooperate a bit. I mean, answer my questions and let me actually help."
This made the Mer scowl again and they seemed to turn away for a bit. Izuku could only think that maybe he was considering things in his mind. Izuku hoped he got through at least a little bit, but he also wished the creature would warm up to Shouto. Otherwise this would be hard.
"Tch. Fine. If this isn’t your hollow, just bring me to it. And I accept your… Terms," the Mer huffed.
Clearly the Mer also needed to set their own rules to feel like they were still winning this. Izuku was fine with it, but moving the Mer to his apartment? Well, it had to be possible since somehow Shouto had gotten them here last night alone. "Okay, Merm-," Izuku paused. Oh. He didn’t even know the Mers name, what should he call them? "What’s your name? Or just, what should I call you? I’m Midoriya. Midoriya Izuku. You can call me whatever."
"Katsuki."
Izuku's face brightened again. He really felt like he had made so much progress with the creature, Katsuki, in a short time. Getting a name and an agreement felt like a big achievement.
"Great! Katsuki it is!" Izuku beamed. "I’ll talk with Shouto once he’s back about moving you at night." Izuku could hear another scoff from Katsuki, but a bit softer. Izuku hummed as he grabbed the bags from the floor and headed to the door, "I’m going to take these to my apartment. I’ll be back soon."
–
A little bit after midnight Izuku sat down on his sofa with a loud sigh coming out of his mouth. Somehow he was super tired. They had just gotten Katsuki from Shoutos apartment into his. Izuku had made the water ready in advance, even showered himself, because now he would have a Merperson taking his bath. It was lucky that these apartments even had bathtubs in them. He would probably need to go to bathhouses after work, which wasn’t optimal, but he’d manage.
Katsuki had not yet let him look at his injury, but Izuku was sure he’d get there at some point. He had peeked a bit while they were carrying him, but if he was honest he had been way more focused on other things. Abruptly he shook his head and buried his face in his hands. He needed sleep. That had to be it.
–
Next five days moved on with pretty much the same pattern. Izuku would get up, put the Methylene Blue into Katsukis tub, and give him something to eat with the antibiotics before he left for work. After work he’d change the water, feed the Mer again the same way and they’d talk.
In those five days Izuku had learned a lot about Katsuki, little by little. The creature had been vary for a while about sharing anything too revealing about his home or family, but yesterday he had really opened up. Maybe it had helped that Izuku himself had been really open about all parts of his own life from work to family, to even past relationships and to his favorite foods.
This was also something that happened now daily. Him sitting on a chair in his bathroom, eating his lunch while Katsuki was also eating his. "Think you’d let me see the wound today?" Izuku asked after swallowing a bite. "I mean, we could maybe end your treatment and let the rest happen naturally, but I’d need to see," Izuku talked before raising the chopsticks back up to his mouth to eat more.
Katsuki seemed to stop eating for a moment and a familiar scoff escaped his lips. Izuku chuckled a bit. "No."
"Why not? Don’t you want to get better?"
"Tch," Katsuki didn’t even look at him again, "it’s not healed yet."
"Ah, of course it still isn’t, you lost a fin! And a lot of skin… But," Izuku continued, "I just need to know it’s healing. I haven’t noticed any infection response from you, but don't you want to return home sooner rather than later? Or not at all if you catch something worse?"
Izuku was actually worried. The injury wasn’t just a small nick in the Mers scaley body. It was a huge chunk of scaly skin missing with a whole fin with it. The Mer could probably also heal at the sea if the injury looked better already, but he probably couldn’t yet leave Katsuki. He had to be sure the Mer would be okay.
Katsuki seemed to think hard on it, eyes once again locked into him. Izuku tried his best not to look away, but that gaze made his stomach swirl so he had to give up. He had really been able to relax while talking with Katsuki and he was already getting used to the presence. It didn’t feel at all like an inconvenience to have him here.
"Fine. After dinner," Katsuki said, before getting back to his dinner of raw fish.
–
Izuku had to help Katsuki get his tail out of the tub. The whole motion made Katsuki curse, which Izuku really understood. The space was really small for such a huge creature. He really wished he could get the Mer back into the sea soon. He’d feel much better not needing to contain such beauty in his small bathtub.
Izuku let his hand go over the scales a bit, slowly. The injury really was gnarly looking. He really had just seen it twice at this point and it didn’t get easier. He felt so bad, he at least knew that actual fish didn’t grow their scales back very fast. It took such a long time. And the fact that Katsuki was now clearly just missing a fin which he had on the other side of the tail at the same spot made him sigh.
"Stop fucking mumbling again. What is it?" Katsuki scoffed, impatient as he lay his hands on the side of the tub and had his head resting on them.
Izuku hadn’t even realized he had kind of zoned out, still letting his hand just slide over the healthy scales. "O-oh. I think considering the damage it looks like it’ll heal, but," Izuku let his gaze back down to the tail, "it’s such a shame. Such a beautiful tail."
Suddenly Izuku heard a splash and Katsukis upper half had just gone underwater. Well, that wasn’t new, but they’d been in the middle of a conversation. Maybe Katsuki just wanted to take advantage of the moment he had more space because of the tail being out of the tub.
Izuku frowned, but got back to looking at the tail. The tip seemed to move a bit, like the tail of an agitated cat. That made Izuku chuckle slightly, before he went back into examining the tail.
After Izuku was sure the tail was looking healthy considering everything he moved back a little. He gave Katsuki his time to stay underwater before he would attempt to get the tail back into the tub.
–
It took some time before Katsuki came back to the surface. Izuku had only left once for a bit, otherwise he had just stayed put. This really had been his daily routine the whole week. To sit at this chair, talking to Katsuki so he didn’t really even want to think or remember what he had done before the creature appeared into his life.
"Welcome back," Izuku smiled, "we should get your tail back in, unless you want to have it out longer? I don’t mind watering it once in a while if you prefer that."
Katsuki seemed to contemplate and in the end he huffed, "am keepin’ it out."
Izuku noted the answer, before he scooted his chair a bit closer to the tub. He had been sitting in silence with his own thoughts for too long already. And something seemed to be on Katsuki’s mind and so far he knew that talking was the best option to get him to say what he wanted.
"Okay! So is the tail otherwise feeling fine? How do you usually deal with injuries, is it okay to go back to the ocean already? I know you said you live deep so would you be able to get there like that? Like I’d think it would put too much strain on it to swim for a long time. But also I am not an expert, I really focused on rodents in my studies. I’m not saying I want you to leave, it’s actually been really fun to talk to you and learn. Like who would’ve thought not all tales are true–"
Izuku was interrupted by salty lips on his own, a hand grabbing his shirt by the chest to pull him even closer to the tub. Izuku felt his face grow red as he pushed his lips against Katsukis own in response. The kiss was short and rough, leaving Izuku no time to think about what had just happened.
"Tch. Wouldn’t even give me a second to answer," Katsuki growled, bashful. Izuku could catch the slight tint of red around the Mers neck. Still, he was speechless after the whole thing. Had he just kissed the hot, injured Merperson in his bathtub?
Katsuki let go of Izuku's shirt, "the tails fine. Can’t go long with it, you're right. So I’d rather not…" There was a long pause in which Katsuki was just staring right through Izuku again as he had done so many times before. This time though it twisted Izuku's guts even more than before. Katsuki turned his gaze before continuing, "leave yet."
"O-oh, yeah th-that’s totally fine. Like I don’t really want you to-to leave either and it’s no problem taking care of you and I’m not really bothered so I rather you stay as long as you feel you need and –"
"Oi, breathe."
And Izuku did, sharply at first. He had gone off into a ramble once again. "Sorry," Izuku mumbled, turning his gaze down a bit. He was still feeling weird after the kiss and what Katsuki had said really didn’t help the feeling at all. Katsuki probably really didn’t want to leave because of the injury, but Izuku could feel his brain latching on little things. He hoped the reason was something else entirely, injury just being a tiny part of it.
–
Even when Katsuki no longer needed the care, Izuku still spent the same amount of time with the Mer in his bathroom. Nothing had really changed, except the Mer now seemed to kiss him everytime Izuku gave him food. Izuku always heard a low voiced thanks after, before the Mer would just move to eat. Izuku didn’t know what to think about that. He couldn’t say he disliked it. More like it made him warm and confused. He didn’t have it in his gut to ask if it was just a Mer way to say thank you properly.
–
"Ah it’s getting late. I better go bathe," Izuku said, getting up from his chair which had been right by the tub for over a week now.
"Just bathe here you idiot," Katsuki scoffed, "You can fit fine here if we just lift my tail out."
Izuku looked up at Katsuki, who seemed to be serious about it. The words made Izuku blush, hard. Him? Bathing with Katsuki? His hands raised automatically to cover his face in embarrassment.
"I-I can’t do that! That would be too– Oh my God," Izuku whined, shaking his head to get rid of his thoughts. "I– I’ll be back soon!" he said in a way too loud and squeaky voice as he fled the bathroom. It left Katsuki frowning in the tub, moving to lean on the edge with his hands. What had he said wrong?
–
"I’m back!" Izuku exclaimed as he got back home from work. He was humming along some random tune. It was Friday, it had been nearly three weeks with Katsuki in his care and going home felt like something he really waited for. Usually he had loved to stay at work longer with all the cute critters, but now there was someone actually waiting for him.
"Took you long enough," Katsuki scoffed, stretching out his hands, ready to get his dinner.
They were eating in comfortable silence and once both were finished Izuku beamed at Katsuki. "Hey, Kacchan," he giggled, "can you come closer for a bit?"
Katsuki looked suspicious, still getting used to the new nickname he had been given a few days ago. "What is it nerd?"
"Just come," Izuku enticed.
Katsuki rolled his eyes and moved closer to the edge. Before he could even realize what was up he could feel Izuku very close to him. First he thought it was for a kiss, but they were cheek to cheek, before Katsuki felt something cold against his chest. He hissed a bit, which made Izuku giggle before he leaned back.
"It looks good on you Kacchan."
Huh? Katsuki looked down, just to see a huge piece of jewelry on his chest. It had long, thick stones on it, metal, which Katsuki could tell by smell alone was gold, coral and small, beautiful pieces of Unakite.
"I thought of you when I saw it. The gold is a bit much, but the coral reminds me of your eyes and the jewels… I think they’re exactly like your scales, maybe a bit lighter, but right where the oranges meld to the dark green."
Katsuki just listens to Izuku talk. He just can’t look away, and he can’t believe it. Had Izuku just really given him a courting gift? And a beautiful one at that, with an even more beautiful explanation? Fuck. Katsuki knew what it meant if he accepted it, but he was too flustered to think. "Thanks," he said barely audibly, before just submerging himself into the water. He could barely do it with his tail in the tub, but he needed the little cover he could currently get. The nerd had to know what giving a Mer outside your family jewelry meant. Why wasn’t he flustered at all?
Izuku was a bit disappointed that Katsuki had just gone underwater. He had learned some things about the Mers' habits. And always when Katsuki went under he had either sulked, been embarrassed or angry. Izuku truly hoped it wasn't anger. Katsuki had said thanks after all.
"I’ll go bathe since you seem to need time. I’ll be back soon, Kacchan."
–
It had been another week after Izuku had given him the gift. Fuck. Fuck . Fuck . Katsuki had accepted the gift, keeping it on, and he wanted to give his own gift in return, but he had nothing. In this bathroom nothing was really his. He was frustrated. He missed his home, his family and the access to everything he used to have.
Thinking about it had really run his thoughts into a spiral. It had been a bit over a month after all since he was washed to the shore. Thinking about home had been a mistake.
Katsuki had not even realized he was crying, until Izuku came home with the usual cheer in his voice. Though once he saw Katsuki, his face changed instantly to a worried expression.
"Oh no Kacchan what’s wrong? Is it the tail? Does it hurt?" Izuku moved right to the tub.
Katsuki shook his head and without thinking just wrapped his arms around Izuku's torso. Izuku bent over a little, so he could get his arms to Katsukis neck. "Shh, I’m here." Izuku didn’t ask anymore questions. He let the other just cling to him. Katsuki would talk to him if he needed that.
They just stayed there for a while, before Katsuki moved, wiping his eyes to his palms. "Could you," Katsuki took a shaky breath to steady his voice, "join me?"
"In the tub?"
Katsuki just nodded and this time Izuku just smiled. If it was what Katsuki needed right now he would do it. He took off his work shirt and pants, leaving his boxers on before climbing in. Katsuki had made him some space, and as soon as Izuku stood in the tub he pointed behind himself. Izuku took the hint, and with a bit of shuffling around he was soon sitting, his back against the tub, Katsuki in his lap.
Neither of them said a word. They just laid there in silence for what felt like hours. Izuku’s hands wrapped around Katsuki, fingers sometimes lazily tracing over a few scales.
–
And too soon it feels like his tail is healthy. At least for him to be able to comfortably travel underwater long enough times to not be a prey. Once he let Izuku know he could feel the air get heavy.
"I see. That’s – That’s good news," Izuku said, trying to sound cheery, "so do you. Want to go tonight?"
Katsuki had already fought with his thoughts previously, still it was hard for him to say the words now. "If possible."
Izuku nodded, his chest felt tight, as he just got up. "I’ll go tell Todoroki." And he left the bathroom, left the apartment, just to crash himself to the railing opposite his door. It hurt. Why did it hurt this bad? Izuku gasped, trying really hard not to let himself cry. Katsuki had been away from his home for almost six weeks. Of course he wanted to go. He needed to go home. He understood it, but still he felt hurt by the whole situation. It seemed like he really had been just a fool with his thoughts.
–
That night Shouto and Izuku did carry Katsuki back to the shore, where Shouto had found him nearly six weeks ago. They laid him down on the sand close enough, so the sea could touch the Mer.
"S-so this is it huh?" Izuku lets out, trying his best to smile. He’s happy for Katsuki, truly. Shouto had moved a bit further from them, giving them space after saying his goodbyes first.
"Yea. Thanks nerd."
Izuku wants to cry so badly, but he can’t let himself be weak.
"Oi, stop being sad", Katsuki frowned, pulling Izuku by the hem of his shirt hard. Izuku fell to his knees, yelping. Katsuki let his hands cup Izuku’s face as he looked straight into the others eyes. "It’s not the end of the world idiot. You think I’d be stupid to just leave my mate?"
"H-huh? Mate?" Izuku didn’t even realize tears had already started falling, but now he was stunned. He had read something about that when he was researching Mers.
"Yea, I accepted your shitty courting gift you dumb fuck," Katsuki scowled, "so stop crying."
Izuku still didn’t understand, his brain working overtime trying to decipher Katsukis words. He was confused, but when Katsuki pulled him for a kiss he didn’t fight back. He leaned into it, savoring the salty taste.
"Tch, now you taste like a fucking lionfish. Damn crybaby."
Without saying anything more or letting Izuku talk, Katsuki turned around, letting himself be submerged into the sea. With the flow of the water around him, his body remembering all that he had missed, he kept going. The sea felt good around him, welcoming. Determined, he kept going, not letting himself get emotional. He was not a sap. Him and Izuku would see each other again. As soon as he found a damn perfect return courting gift for his mate.