Chapter Text
The sand between his toes is comfortably warm, and the breeze off the ocean is cool. Izuku inhales deeply and closes his eyes. He can taste the salt in the air, briny on his tongue, and his shoulders relax the longer he stands in the surf, water lapping gently around his ankles.
Maybe this forced vacation wasn't such a terrible idea, after all.
"I owe Recovery Girl an apology and a gift basket," he murmurs to the seagulls overhead, thinking sheepishly of the whining he'd done back in the city when she'd first told him to take time off.
No arguments, mister, she'd said with a frown. As your doctor, I'm making it mandatory. You need to rest and let yourself heal properly.
I'm fine! he'd tried to assure her, but she hadn't budged.
You were in a coma for two months. Her eyes had been full of worry beneath the sternness. And it's not just your body that needs to heal.
He hadn't been able to counter that one.
The call of the gulls is the only sound to hear next to the gentle susurrus of the waves. Definitely a change from the rush and noise of the city, but he decides it's not a bad one. It might even, maybe, be one he should indulge in more often.
He huffs a laugh. "My poor assistant might just keel over if I tell him I'm actually using my vacation time of my own volition. It would certainly take everyone off guard."
His muttering trails off as he walks along the shore, enjoying the warmth of the sun's rays on his skin and the way the wind tousles his hair. The resort they'd sent him to is one of the nice high end ones, used exclusively by Pro Heroes. With its own private beach sequestered away from the hustle and bustle of the rest of the country, it's like being in another world entirely.
He's done a bit of exploring in the week or two he's been here already, the adventurer in him pushing to the front and leading him on little "expeditions" along the waterline. Today, his goal is a rocky outcrop around the bend from the resort's main beach area. It looks like there might be a cove with tide pools hidden behind it, and he's excited to check it out. He's no marine biologist, but Tsuyu is, and he knows she'll appreciate the photos of whatever fish he sends her.
Waterproof camera in hand, he climbs over the rocks with mounting excitement. He uses his quirk to keep from slipping more than once and laughs to himself the third time he catches himself from taking a nosedive into the water.
"It's like I'm challenging fate," he says to a hermit crab he finds tucked into a crevice in the rock. "I'm daring it to knock me into the water just to show me who's boss. At this rate, it's probably going to win."
"Something's gonna knock you into the water, alright, but it won't be anything as nebulous as fate," a voice says, tone wholly unamused.
Izuku startles so hard that he forgets to use his quirk to catch himself as he slips from his perch on the rock into the ocean.
The water is on the warmer side of cool, thankfully, and he comes up sputtering and spitting it from his mouth. He drags a hand over his face to move his bangs out of his eyes, treading in place. A soft, ugly snorting sound draws his attention, and he turns to see whoever had spoken to him.
Red eyes watch him from a perch on another rock a few feet away, amusement shimmering within them. The breeze tousles blond spikes around an angular face, and sharp teeth poke out from sneering lips. Izuku's gaze drops to broad shoulders and very defined biceps crossed over pectorals so pillowy he feels the briefest urge to lay his head against them and then down to—a tail.
A tail?
Easily twice Izuku's height, the tail—because oh, gosh, it is in fact a tail—is all sleek black scales with a beautiful burnt orange underbelly. The end of it disappears over the rock's edge, and he can just make out the lazy sway of tail fins through the crystal clear water.
A tail.
Is it a quirk? It must be, right? Because there's no way it could be what his brain is making him think it is. Quirks are so varied, anyway, and with mutant quirks that completely change a person's physiology, it's absolutely possible for someone to end up half-fish—
"God, do you ever shut the fuck up?" the stranger groans, and Izuku's mouth snaps closed, his mumbled words cutting off. "You've been doing that all week. It's gettin' on my damn nerves."
"I'm—Sorry?" Izuku replies, too bewildered to take offense. "It's, uh. Habit, I guess?"
The fish-man—merman?—scrutinizes him for a moment, before rolling his eyes and looking away, dismissive. "Tch. Humans."
He pushes himself off his rock and slips into the water with a small splash, then pauses. Izuku can't read the expression on his face before he finally swims away with powerful strokes of that amazing tail, disappearing into the depths.
Izuku watches until he can no longer see him or his tail. A soft brush against his ankle has him looking down to see a school of fish bravely coming to inspect him, and he remembers he's still in the water. He should get out and dry off before he catches a cold or something.
Pulling himself back onto the rock he'd slipped from, he looks down at the hermit crab.
"I think I just met a merman," he tells it. He glances back toward where the merman had disappeared, a fluttering feeling taking root in his chest when he thinks of those red eyes and rough voice. "He was very handsome. Kind of rude, though."
As he makes his way back to the resort, waterproof camera dangling from his wrist and all but forgotten, he wonders if he'll see the surly merman again.
He does see the surly merman again. Nearly every day he goes down to the beach, in fact.
The merman's name is Katsuki, and at first Izuku meets him at the little cove of rocks where they first interacted. Katsuki sits on one of the rocks and mostly observes while Izuku explores the tide pools, taking pictures of the marine life below the clear water. He says he likes the warmth of the sun; it’s so different from the cold, deep trenches his kind tend to make homes in. Izuku finds him napping in the rays beaming down several times.
Katsuki begins meeting him at the beach just down from the resort after Izuku offhandedly mentions he's the only Pro Hero there at the moment. It's clear he doesn't want to be discovered—or at least doesn't want lots of attention—and Izuku respects that. It turns out his tail is not a quirk; he truly is a merman, a creature of myth, and Izuku vows to protect him from the deadly curiosity of his own kind.
What kind of hero would he be otherwise?
They get to know each other slowly, a little bit at a time as the days of his vacation pass. Izuku talks freely about many things: his day to day life, his friends and family, his job. Katsuki listens and responds in kind, with shorter answers, and Izuku eats up every little tidbit. He even asks questions sometimes, lying on his stomach in the sand while his tail sways in the air.
The genuine interest he shows in Izuku in return makes that fluttering feeling in his chest act up each time. He finally admits to himself that he likes Katsuki—truly, genuinely has feelings for his new grouchy aquatic friend—and that those feelings might even be reciprocated when he starts finding sea glass and little trinkets left in deliberate piles in the sand.
There's no way to know for sure without directly asking Katsuki, no books he can read or anyone else he can ask, but Izuku is positive it's a courting gesture of some kind. Offering a potential mate gifts is a common thing among a bunch of other species, though—even humans, really—and his heart swells more and more with each thing Katsuki gives him: the trinkets and himself in each little piece of information he shares.
It makes the knowledge that he'll eventually go back home, leaving Katsuki and this little piece of paradise to return to his duty as a Pro Hero, weigh that much heavier on his shoulders.
Izuku sits on his rock, gazing out at the lazy rolling waves while the breeze tousles his hair. It's early enough that the heat of the day isn't too bad yet, the sky a cloudless blue, and he inhales the familiar briny scent of the ocean on his next deep breath.
He's going to miss it. A lot.
A soft splash has a smile curling up his lips. He looks away from the horizon to watch Katsuki pull himself up onto the rock next to him. When the sun's rays catch it just right, his tail looks like an oil spill, the black shimmering with subtle hints of blues and greens as water cascades off it. The burnt orange underbelly bleeds into it in a way that makes it look like it's caught fire and is ready to explode.
He blinks and scrunches his nose when water is flicked into his face, and he pouts at the grinning merman next to him.
"The sun's barely up and you're already lost in thought, hero?" Katsuki teases. His sharp teeth are bared when he smirks, but Izuku has never been afraid of them. "You're gonna overwork that little brain of yours."
He splashes back out of pettiness even though Katsuki doesn't bat an eye. "You're so mean to me, Kacchan," he grouses, but it's half-hearted at best. He's not up to their usual level of banter today.
Katsuki immediately picks up on it, his grin dropping away to a concerned frown. He peers at Izuku with narrowed red eyes. The flared fans on the side of his face flex.
"What's wrong?"
Izuku inhales deeply again, holding it for a beat before releasing it.
"I'm leaving soon."
The words come out such a soft murmur, he's afraid they're lost in the wind. But Katsuki's hearing is much better than a human's, he's learned, and it's obvious he heard Izuku in the way his jaw clenches and his red eyes go dim as he looks away. Izuku's own eyes burn with coming tears.
"How soon?" Katsuki asks after a moment, and Izuku looks back at the horizon.
"Tomorrow," he answers quietly. He picks at the hem of his shorts. "I'm sorry I—that I didn't say anything sooner."
I'm sorry I let us get this attached just to leave you in the end.
Silence settles between them for a bit, broken only by the susurrus of the waves and the call of seagulls. Then Katsuki clicks his tongue in that way that Izuku has learned means he's come to some kind of decision and turns to face Izuku. He holds his hand out, and Izuku blinks at the necklace dangling from it.
Fish bones and shark teeth are strung between large beads of red sea glass, similar to the necklace Katsuki himself wears, though his beads are more of a green-leaning turquoise. The fish bones have been carved into unique shapes, and he's awed at the level of craftsmanship and obvious care in it. His heart beats heavily against his ribs, soaring and aching in turns. This is definitely a courting gift.
Blinking back hot tears, Izuku looks into Katsuki's pretty red eyes. His lip wobbles as he asks, "Kacchan?"
Katsuki's cheeks are lightly flushed, but he doesn't look away. "You've accepted all my other gifts," he murmurs, licking his lips before continuing. "This is the last gift before the official mating. I think you humans call it 'getting engaged.'"
"You're proposing," Izuku realizes with a laugh. He wipes his eyes. "You want to marry me?"
Red eyes narrow at him again, but this time in uncertainty. "If by marry, you mean be your mate, then yes."
Heart swelling with warmth, Izuku reaches out and carefully accepts the necklace. He drags his thumb over the bones and teeth and beads, marveling at it, before slipping it over his head. The bones click softly as they settle against his chest. He looks at it with a smile before turning it up at Katsuki, and Katsuki smiles back, gentle and full of fondness.
It fades a little as he hesitantly asks, "Will you come back?"
The giddiness of the moment leaves, replaced once again by aching and longing, and Izuku swallows thickly.
"I want to," he answers truthfully. "But I have a duty to my people, a responsibility to protect them. I don't know how often I can leave it behind, even for a little while."
Katsuki looks away. "I get that," he says, gaze distant, and Izuku knows he does: being the leader of an entire pod of his people, responsible for their health and safety and happiness, isn't that much different than Izuku's role as a hero.
Following the urging of his heart, Izuku leans forward and presses a kiss to Katsuki's cheek. His skin is smooth and slightly cool beneath his lips, and there's surprisingly no taste of salt to be found. He lingers long enough that when his merman turns his head, it brings their mouths together, and he sighs into the kiss with contentment.
They part again slowly, reluctant to move away. Izuku opens his eyes to find Katsuki already watching him.
"I'll miss you," he admits, heart already aching. The tears he's been holding back finally start slipping down his cheeks. "I don't know when I'll get to see you again."
Katsuki reaches up and brushes them away with his thumb, then drops his hand to tug gently at his necklace. "I'll come back here, every year," he says, and it sounds as much like a threat as it does a promise. "And I'll wait for you until you can come back to me, Izuku."
The tears come harder. Izuku buries his face in Katsuki's neck, holding him tightly. Katsuki holds him back, and they stay like that until the sun goes down.
Izuku walks into his agency and is greeted by a smiling Ochako.
"Deku! Welcome back!" she says brightly. "Oh! I like your necklace! Where did you get it?"
He smiles as he fingers the red beads and shark teeth, thinking of the red eyes and sharp grin they're meant to match.
"Thanks, 'Chako. It's just... something the ocean gave me."