Chapter Text
Bakugou Katsuki was going to become a pirate. There was no maybe in there, it was a certainty. They could just try and stop him, and they’d see how badly it went for them.
He had no interest in becoming chief of the warrior clan he’d grown up in, his ma wasn’t going to die for at least another forty, fifty, sixty years so why was she trying to rush him so much?! He had things to do first. And besides, he wasn’t interested in the slightest in all the women she picked out for him, not that he bothered to analyse too deeply as to why.
First of all, he needed to find someone who could actually fight. He was going to be the best, better than his ma, better than the chief before her who had single-handedly won them their entire territory. He would be stronger than All Might, even if he was the most powerful chief to ever live, see if Bakugou cared. And Deku too, not that he thought the crybaby would ever be on his level, but…safety precautions and all that.
So he needed an opponent who could match him in strength, and rumor was that there was a ship on the high seas unlike any other. One whose captain was a siren, able to sink ships without ever boarding them. The Lullaby floated out of the mist, black flag waving in the wind, and by the time its towering shape could be seen the low humming of the creature sitting in the bow of the ship was already the last thing you knew before you woke up days later, robbed blind and bound in a line with the rest of your crew. Those were some of the rumours at least. Every second person he spoke to said that the first mate was a murderer with bright red eyes who devoured the hearts of men for fun. And every third person he spoke to said that that was wrong, in fact the first mate was a sea monster. If your ship began sinking for no reason, it was because its hull had been torn open by the clawed hands of a beast so quick and powerful that you would never see it, the interior set alight by ghostly blue fire that wouldn’t extinguish even in the water. A ship that burnt all the way to the bottom. They said that this was a creature that tore out throats with its bare hands and obeyed none, not even the Lullaby’s feared captain, Hawks, himself. Rumour said, if you fell in the water with it you perished instantly. Others claimed that it wasn’t that the creature refused to obey Hawks, it was that Hawks refused to stop the monster from killing whoever it pleased. A dog with no leash to do as it wished.
Katsuki didn’t believe them. But there was no question that the ship in all the rumours was called the Lullaby.
And in all her glory, he was standing right before her, docked and collecting supplies at the port just like he’d been told she would be. No other ship had moored beside her, none dared. The entire city guard was running through the streets at this very moment, armed and ready to intercept a crew of phantom pirates who supposedly couldn’t be killed.
Katsuki watched them load the last of the crates onto the deck—filled with fresh fruit and greens, caskets of water, ale, wine and rum, bags of salt and sugar—and thought that the city guard would never even get the chance to test their strength against them. They would be long gone before then. It was now or never.
He hopped up onto the ramp that led across to the ship and jogged lightly across, his rucksack shifting over his shoulder with each step. He had a broadsword strapped to his back, but it was wrapped in fabric that he hoped made it less obvious. Like he would need it anyway, no one could fight like he could, he’d been raised with a bloody fist and murderous grin. The nickname their tribe had—of being barbarians— wasn’t so far off in his opinion.
The first thing he noticed upon landing silently on the bulwark behind one of the big crates was that nobody had seen him sneak in. He’d planned on confronting the captain straight on, but when he cast his eyes over the crew he couldn’t quite tell…who the captain even was. Ah…somewhere in his mind he’d decided that a man with such a dangerous reputation would at least look different from the rest of his crew, but apparently that was a slight miscalculation on Katsuki’s behalf. Or perhaps the captain wasn’t here yet. There didn’t seem to be anyone in particular ordering the crew around, they just completed their tasks with an easy familiarity.
Half an hour later, when the boat had long since sailed out of the port and the sails had gone up, leaving the crew with more time on their hands to start unpacking, Katsuki still hadn’t decided on who their boss was. But they’d left port so he had to be here. They wouldn’t have sailed without his order.
He rose, determined to at least confront someon —
A bright, hot, flash behind him had him spinning around just fast enough to be barrelled onto the slick deck floor by a…body?
The person sat up almost instantaneously, so quickly that Katsuki couldn’t even think to draw his sword.
“Oh, sorry about that.” They muttered, rubbing their head. “My legs gave out. Why did they do that?”
Katsuki stared.
The guy cast duel coloured eyes to him, tilting his head. “Ah, is this the wrong human language? Do you not speak this one?”
Katsuki slowly shook his head, then he nodded slightly that yes, he did in fact speak this language.
“Hm.” His attacker decided, and Katsuki noticed for the first time that he wore no shirt, only some sort of pants, a vibrant red material that gave way jaggedly to a white strip around the waist and ankles. “So you do then.” He considered for a moment, and then slyly almost, he clicked rapidly, hissing once and then whining ever so faintly. When Katsuki did nothing, the strange—pirate? Was he part of the crew? Where the fuck had he even appeared from?!—sighed. “Guess you only speak human then. That’s annoying, I can’t speak it as well as my brother, he’s going to tease me.”
The guy’s gaze traced from Katsuki’s chest to his spilled rucksack at his side. “Ah!” He said, “You have another human torso garment, let me have this.”
And he dragged Katsuki’s spare shirt from the bag and quickly pulled it over his body. Katsuki would have complained, except that the perfect abs had been somewhat distracting.
Once that was done, the male climbed unsteadily to his feet, nearly falling back over when the boat tilted. “Okay, take me to your King.” He demanded calmly, like orders were as natural to him as breathing.
And in all Katsuki’s notable intelligence, the only thing he could come up with was the dumb response of, “I am the King.”
And that was supposed to be a goddamn secret.
The strange guy leaned forward, narrowing his eyes. All at once, he dropped back into a crouch and leaned over Katsuki once more, poking his chest with a slim finger. “Where are your rankings?”
“My…what?”
The other looped his thumb around the necklace he wore, drawing it out from where it had been obscured beneath Katsuki’s shirt. “See, the scales of the opponents you’ve defeated.” He gestured to his earrings. “And the shark teeth that the shark clan give you when you turn twelve.” Then he shook his wrists. “And all the tokens of faith from your people.”
Katsuki could only frown, and the other poked the necklace he wore, made of wolf and dragon teeth. “Ah, is this it? I suppose human’s don’t have scales. So you rip their teeth out instead.”
“…huh?”
And that was all he managed to say before the odd human shoved his fingers in his mouth, prying open his jaw to examine his teeth like it was completely natural.
“Such blunt fang—eep!”
The only warning Katsuki had was a large gust of wind and the sound of what registered in his mind as a massive bird landing before his attacker’s weight was all at once gone, and the next thing Katsuki knew he was also being dragged to his feet by a firm grasp on his shoulder.
“I don’t have much patience for laziness in my crew…” Someone began to say, then paused. “But you two aren’t a part of my crew now, are you?”
Katsuki could only stare at the figure beside him, and the massive red wings sprouting from his back, dumbfounded.
“Great…” Hawks, the single most dangerous pirate on the high seas, muttered to himself. “More stowaways. The first one was bad enough.”
Someone hopped easily up the stairs to their left, a woman with white hair and a dog-eared pirate hat. Blood-red Miruko, Katsuki realised, more spooked than he would ever admit.
“You say that,” She snorted. “But you’re just soooo in love with Dabi that it’s not even funny at this point.” She puffed out her cheeks. “And here I thought it would just be a short-term infatuation.”
Beside him, the boy with duel-coloured hair perked up, a soft chirrup of recognition rumbling in his throat. The sound had Hawks pausing, his eyes narrowing as he regarded them both properly for the first time. Katsuki watched the way the pirate catalogued the sword at his back, the numerous teeth on his necklace—all hard won. He’d wrestled every one of those creatures to claim their fangs—and then flicked to the obnoxiously glimmering pants of his attacker before it travelled up to the red and white hair, and hopeful, blue and brown eyes.
“Touya is here!” He said, excitement obvious in the low purr that followed, a sound that had Katsuki staring at him because he’d never in his life heard a human purr like a cat.
Hawks regarded him shrewdly, as though he were analysing the threat of this boy. Katsuki snorted softly, like hell could someone his age actually be strong. Katsuki was the one and only exception.
“Touya.” Hawks finally called, gaze flicking down below deck. “There’s another sailfish mer.”
He added doubtfully, glancing once more at the red and white hair, “I think…” before he promptly tossed the boy overboard, as simply as if he was flicking lint off his shirt.
Katsuki had time to meet surprised blue and brown eyes before the boy was gone, and he jumped to the railing with a shout, leaning over. “Hey!” He yelled, whipping around to face Hawks. “What the hell do you think you’re doing?!”
Very few people could swim well enough to stay afloat in general, but if Hawks wasn’t planning on stopping the ship then the only chance he had at surviving was swimming back to the shore, and if he didn’t get chomped by a monster on the way there he’d definitely drown of exhaustion or freeze before he made it. Katsuki’s sword was half off his shoulder, one hand already undoing his topmost buttons, by the time the splash of the body hit the water.
He startled when water droplets splashed in his face, and looked over to see Hawks curiously flicking water at him. “I know where he came from, but where the hell did you come from? You’re just a human.”
Katsuki could spare him no thought, too busy searching the water to find his sort-of-attacker, who still hadn’t surfaced.
“Another sailfish mer?” A new voice said behind him, yawning at the same time as he heard them walk lazily up the stairs. “How many do I have to chase home before my father gives up, do you think?”
“Hello mate.” Hawks greeted softly, and Katsuki looked over his shoulder in time to see Hawks lower his wings in greeting for the newcomer—a slim man with terrifying turquoise eyes and an air about him like he could become deadly in an instant. “Careful with this one, he didn’t look much like the others.”
“Oh?” Was the interested response. “Did he finally send something a little stronger after me? Was it a shark, or maybe a black dragonfish? This could be fun.”
Without preamble or warning, he hopped up onto the railing, and for the second time in a matter of moments Katsuki watched someone jump into the writhing ocean below, black and deep and dark.
Almost instantly the water began to thrash and churn with bubbles, and then a long tail became visible before it submerged again. Suddenly Katsuki could make out flashes of claws, and then the flukes of some sort of fish, and then there was a red flash—like some sort of seaweed had illuminated underwater—and all at once the sea went perfectly still.
The white-haired pirate who had stepped off the railing without an ounce of fear suddenly broke the surface, only now he had long fin-like ears and a mouth full of razor teeth.
“ Shouto?!” He exclaimed, startled. “Why are you here?!”
A second form rose, this one latching onto the first immediately, clicking and purring and chirping and whistling all in what was clearly happiness.
“Shouto…” Hawks repeated, leaning past Katsuki with a frown. “As in…?”
“Fourth prince of the sea, ruler of the glacial regions, heir to the throne, and my…youngest brother, aye.” The white haired pirate muttered, voice carrying easily up.
Katsuki finally got a good look at the second form. It was the boy who’d landed on him, but he didn’t look the same now.
And he understood, all at once, what they were.
“Mer. You’re both…fucking mer .” He murmured, a slow grin spreading across his mouth. He’d never fought a mer before, but everybody knew that they were merciless killers. Powerful. Strong. Deadly. “Hey!” He shouted overboard. “Come up here and fight me!”
Water rained down on him and he closed his eyes to keep it from getting in them. By the time he opened them again the two were standing on deck once more, now fully human and both dry. Katsuki drew his sword, the taste of triumph already on his tongue.
“Who’s this guy?” The white haired one—Touya—asked, raising an eyebrow.
“He’s the king of this ship.” Shouto answered confidently.
“Hm,” Hawks hummed. “Wrong. Next guess.”
“I’m not the king of this ship.” Katsuki growled. “I’m Katsuki Bakugou—”
“—next chief of the Bakugou barbarians. Yeah, I wondered about that. Didn’t realise you were one of All Might’s clan, I haven’t seen that guy in ages. Now it’s no fair to call sirens and mer monsters when there’s a human that exists like All Might. I’ve never seen a creature with more muscle in my life. And would someone care to explain to me why I have, not one, not two, but three royals on my ship right now? Miruko, are you secretly from an ancient bloodline too? Is that what I’m going to hear next?”
She just shrugged, chewing on a carrot like this was the most entertainment she’d had in years.
Katsuki slowly looked at the overgrown parrot that he’d been told was a siren standing next to him. Said parrot winked, and opened his mouth like he was going to keep talking. “Shut up.” Katsuki said stoutly, and the pirate captain’s eyebrow twitched.
“This is my ship, you twerp.”
Shouto’s gaze was fixed solidly on Hawks, unblinking. “Is that my brother’s scale on your earring?” He turned his unlinking eyes to Touya. “Is he your mate?”
Katsuki’s mind stalled. Mate. Yeah, they’d said that before, too, hello mate. But— “Hah? You’re both male.”
Touya and Shouto tilted their heads at the same time. “Do humans not take male mates?” They asked simultaneously, and Touya looked particularly stricken, his head whipping around to face Hawks in alarm.
“Not usually, no. It’s rather stigmatised in fact.” Hawks answered. “In this day and age at least.” A teasing grin sprung up on his face and Katsuki had already started bristling in preparation. “Although I’m sure things will start making sense to you soon, baby Bakugou. Care to explain what exactly Touya’s brother and you were doing when I found you, because it looked pretty condemning to me.”
Katsuki did not turn red. He refused to. “He attacked me! It wasn’t anything else!”
“I didn’t attack you.” Shouto said. “I fell on you. And then you were warm, so I stayed.”
Okay, as much as it pained him to admit it, he really did gape and turn red then. “I—well—you shouldn’t have! Just fight me already!”
He tapped his sword on the ground, drawing attention back to it, to which Hawks snorted like he knew something Katsuki didn’t and Shouto just tilted his head again like he’d never seen a sword before in his life. The duel coloured mer looked from Katsuki to the sword and back again, and then he snapped his teeth softly. He chittered at his brother, looking confused, and Touya’s brow furrowed slightly, equally unsure. He turned to Hawks and whistled shrilly twice and Katsuki was beginning to feel like he was missing something.
It clicked in his mind then that those sounds they were making was their language. They were talking, and apparently Hawks understood. Not particularly well if the expression Hawks made while he tried to work out the sounds was anything to go by, but when understanding finally dawned on his face and then he looked back at Katsuki with that same slow, fanged grin, Katsuki became certain that he was missing something.
“No, no, you’re right.” Hawks assured them. “It’s the same in human culture, definitely. Sure, he’s being a little rude, challenging a royal mer to a scuffle and all but it has the same connotations, don’t worry.” His grin widened. “He’s definitely courting you, Shouto.”
Shouto trilled in excitement, just like a bird and Touya looked skeptical for a moment before he shrugged. “Better than anything my father could choose I suppose…” He sighed.
“Wait! What did they ask you, Hawks?! I’m not—” Katsuki began.
But he had no time to focus on that, because Shouto had rocked back on his heel and then lunged forward and goddamnit the mer was crazy fast!
“Hang on—!” He shouted, before he was barrelled over for the second time that day.