Hi everyone! Instead of posting that oneshot, I decided to try this story out. This story is meant to have seriousness and crack all at once. You'll see why having a merman after you isn't the best thing in the world. Think of it as the MedievalAU with a literal splash of Mer. Most of the time, it'll be about Bakugou being sick of all this shit.

I honestly don't have a clear direction for this. I'm winging it!

It was standard protocol of the of Yuuei knights to remain kneeling and respectful in the presence of their king. About ninety-nine percent of the knights were following that rule.

Bakugou Katsuki had shouted some profanities as his king gave him, Kirishima Eijirou, Iida Tenya and Tokoyami Fumikage their assignment to protect the Crown Prince of Yuuei.

"I HAVE TO PROTECT THE FUCKING NERD?! WHAT SHIT DID HE GET INTO THIS TIME?!" he shouted, Kirishima hurrying to shush him while Iida waved his hands wildly for order.

"Bakugou-kun! You will remain silent before our king!" he stated, boldly getting in Bakugou's face and shoving him into a kneeling position. All Might remained enthusiastic as ever, their strong, merciful king consistently merry.

"That's all right, Iida-kun! However," his tone became curt and unconquerable, leaving no room for further interruptions, "the reason why I am assigning you boys this task is more than just duties as bodyguards. Come with me to the conference hall so I may discuss this further. Midoriya-shounen."

He nodded to the prince, a sheepish boy with forest green hair and wearing simple clothes despite his status. Midoriya faithfully rose and headed to the conference hall, the knights and servants bowing before him. He was All Might's chosen heir, after all. He was given the privilege to take All Might's place as king, being number one in strategy and strength combined. While not physically the strongest, he had the drive and determination no other person could reach. Throw a challenge his way, he could outsmart it and come out stronger even if he broke an arm. His good heart had the people in awe and gratitude. He was going to be the king their people wanted, needed and deserved.

Everything seemed pretty serious. It made Bakugou just a little curious. The fucking nerd was typically able to handle himself despite being a crybaby weakling at times. He was serious when he asked what shit Deku got himself into. He was a magnet for trouble without looking for it.

Midoriya had been out at sea for three weeks with the Shiketsu division to attend to some royal business. He had only returned the night before and they held a dinner party for his return. Everything had seemed normal for the most part.

He rose and followed his group to the conference hall, Iida yapping away about remembering their manners despite being Midoriya's friends.

In the conference room, Midoriya looked like he was constipated or something. He kept looking out the window towards the vast blue sea that hugged the shores of the kingdom. Bakugou could never understand what went on in the nerd's mind. He wasn't going to risk a lobotomy to find out.

All Might sat in his large chair, gesturing the others to follow suit.

"The reason why I have assigned you all as personal bodyguards for Midoriya is because we have a situation that I don't want known by the people. It could send unnecessary fear to the people and halt sea trade. It isn't something people should fear, but we must remain aware and cautious." Bakugou leaned in along with his fellow knights. A secret mission? Midoriya suddenly looked guilty on top of uncomfortable. All Might cleared his throat, folding his hands.

"A merman has fallen for Midoriya-shounen." The silence was so deafening, you could hear a pin drop. A…merman? There was a unison of horror on Kirishima, Tokoyami and Iida's faces. And pure, unadulterated rage on Bakugou's. His knees were on the table as he attempted to lunge at Deku, but Kirishima held him back.

"YOU'VE GOT A FUCKING FISH STALKING YOU?! FUCKING DEKU! I CAN'T LEAVE YOUR DUMB ASS ALONE FOR TEN MINUTES WITHOUT YOU GETTING IN TROUBLE, YOU LITTLE SHIT!" A fucking mer. A species full of shitty yanderes that the knights had learned about during their education. Kirishima and Iida manhandled him back into the chair. Wiping sweat from his brow, Kirishima turned to the sheepish Midoriya and nonchalant king.

"I thought the Shiketsu division was with Midoriya out at sea? How did the mer see him with them around?" Inasa was pretty gungho about protecting Midoriya and had even tried encasing Midoriya in a whirlwind before setting sail. The idea was quickly nixed. How'd they fuck up? Tokoyami was using Dark Shadow to hold Bakugou in his seat as he rubbed his chin in thought.

"It means the Shiketsu division was preoccupied with the storm. I heard there was quite a bit of a turbulence at sea a few nights ago. Midoriya must have been alone when the mer saw him." Midoriya finally spoke, cheeks rosy red like a stupid virgin in love.

"I-I was…b-but it-it wasn't like he was looking for me! We-we ki-kinda just…ran into each other." Mers were known to be seductive. They had once heard of a ship that crashed when a mermaid used her beautiful voice to lure the sea poachers into a cliff. Deku was probably discombobulated. Iida sighed deeply, upset that Midoriya could possibly be under the influence of a psycho mer.

"One look from a mer is all you need for them to become infatuated, if their instincts tell them that you're their mate. They're known for being…persistent? Would you say so, Your Highness?" Iida didn't want to sound so insulting if All Might didn't condone it.

"Persistent is a broad term. Merfolk culture is different from ours. They stop at nothing to have who they desire. Murder is typical." Someone hissed, verbally wincing. Mers were pretty much insane compared to humans. Mers mate for life and had undying devotion to their mates. Well, divorce probably wasn't much of an option. All Might grinned at his uneasy successor and patted his shoulder.

"We will protect you, Midoriya-shounen. We must also act to find this mysterious mer and identify him. If possible, we could do negotiations and come to an understanding. Luckily Aizawa-sensei's quirk can cancel the mer's abilities if he tries to use them on Midoriya-shounen again. Your primary duty is to protect Midoriya." All Might's kind exterior changed to that of a powerful king. "Am I clear?"

The knights rose, Bakugou reluctantly, and bowed.

"Hai!"

"Fuck you, Deku. I can't believe you got mixed up with a mer," grumbled Bakugou, more annoyed than enraged. He had a task now and couldn't waste his energy screaming. Midoriya sighed, feeling a little claustrophobic with his friends in a tight circle around him.

"I didn't ask to have a merman obsess over me…" But it's not like he minded deep down. The mer was super handsome and it was really kind. Maybe it was because the merman had a crush on him, but it made Izuku feel warm and tingly inside. Bakugou couldn't handle all of this shit Deku puts everyone through, even if he didn't mean it. If he weren't the crown prince, he'd whoop his ass and put him in a jail cell.

"Whatever, Deku. We're gonna make sure your dumb ass doesn't get kidnapped or turned into fish food. From now on, I say you stay away from the ocean. Fuck the water. Who needs it anyway? That's like dressing yourself up for that mershit's dinner." Midoriya sighed. As usual, Bakugou was too extreme.

"Whatever you say, Kacchan." Was that...attitude?! Small explosions went off in his hands, menacing fingers pointing at the prince.

"Don't give me lip, you shitty nerd! You know I'm right!" He was soon ignored as the group walked out of the castle to the courtyard. The Shiketsu division were all dressed in their usual armor and chatting with a couple servants and officials. A familiar face caught their attention.

"Ah, Inasa-kun!" Iida called out, catching other male's attention. Yoarashi Inasa grinned broadly and waved at them, beckoning them closer and staring at how the group was surrounding the prince. Bakugou lost his temper again at seeing the reason why they had to do this task to begin with.

"SHIT-KETSU! LOOK WHAT YOU ASSHOLES DID! NOW WE GOTTA WATCH THIS NERD!" Yoarashi straightened instantly and bowed his head low and fast enough to smash his forehead to the ground. He couldn't feel the damage it did, but the results spoke from themselves.

"Our deepest apologies!" As he rose, they all cringed at seeing blood running down freely from a new cut on his head. Tokoyami recovered first and sighed.

"Ignore Bakugou, he's just being a demon as usual." He didn't even flinch when Bakugou gave him his signature glare.

"Shut it, birdbrain!" Tokoyami dutifully ignored him and nodded towards the group as some members were hauling their luggage out towards an awaiting carriage.

"Anyway, are you all setting out?" Yoarashi grinned again when he looked over his shoulder and saw Shishimura give him a thumbs up.

"Yes. We are going by carriage. It's not safe to sail. Our sensei advised us against it because he's afraid the mer will target us." Mers had quirks too. Judging by what they saw, it seemed like the merman they encountered had an ice quirk. Everyone's immediate thought was worrying about sudden icebergs.

Midoriya suddenly felt guilt pool in his stomach. His carelessness put everyone in danger, but no one really saw it that way. All the blame fell on the merman and the storm that caused Midoriya to think he needed to be out there. That made him feel even worse. Yoarashi saw Midoriya's frown and reached a hand out to grab his shoulder.

"Don't be sad, Midoriya-ouji! I would much rather have the target on our backs than yours. Our kingdom needs you more than I will be needed." Midoriya looked up, again frowning. He didn't like it when others would blatantly put themselves in harm's way for him.

"Inasa-kun..." The taller male patted him firmly.

"You don't have anything to worry about. We'll be fine." It was best to assure the prince. The whole division was on high alert now and Inasa could only blame himself for not killing the merman on site. He had only thought to get him away from the prince. Kirishima hummed out loud, scratching his chin.

"What exactly happened out there?" Both Midoriya and Yoarashi hesitated. It was a night they'd much rather forget. Well, not so much Midoriya.

Returning to Yuuei turned out to be quite cumbersome. The storm wasn't settling like they originally predicted, motivating Inasa to use his quirk and balance out the strong winds disturbing the sails. The waters were still rocky, but everyone was able to maintain some stability as they waited the storm out. The main issue was that Inasa needed to be out on the deck to see the winds and control them. Even with his broad stature, he was faltering against the strong currents that threatened to overtake the ship.

Midoriya didn't like the idea of someone risking their life while he sat and did nothing. The others were too busy trying to make sure the rest of the crew was okay to notice that he made a move. He managed to stumble out of his quarters, body glowing with One for All so that he could step in and grab Inasa in case he was in danger. He had done it during the smaller storm they experienced on land. It could work again.

A large wave crashed into the ship, lurching it violently to the side and sending Midoriya flying towards the side. He couldn't tell how he was oriented, but he braced for impact as everything in his sight became a blur.

What met him wasn't the wooden railing of the boat. Instead, he fell into the embrace of soft, powdery snow. The shock of the cold was enough to snap him out of his thoughts, looking around wildly. Someone saved him?

A heavy thud caught his attention as he sat up in the snow, looking over until he saw a sight that contrasted the storm around him.

A merman was looking right at him. He looked around his age, with snow white hair on his right side and crimson red on the left. He had heterochromatic eyes, the left a bright ocean blue and the right a cloudy grey. His tail was massive and long, a mix of silvery white and blazing red that cascaded down to the fins. He looked handsome with the moonlight streaming down as time around them froze. Midoriya's cheeks blushed with appreciation.

The mer seemed to think the same, slowly crawling towards him in awe, reaching a hand out to caress the soft cheeks of the adorable boy before him. Despite the storm around them that was beginning to stop, Midoriya could hear the faint clicking that rose from the merman's mouth. They sounded pleasant to his ears like a soft melody.

"Midoriya-ouji!" Inasa could be seen running towards him with several of his friends, jaw dropping when they saw the being next to him. He was a stronger looking mer than the ones they studied in the books. What disturbed them was the look of adoration in his eyes when he was looking at their prince. He was so enamored that he didn't notice them approach.

"A mer!" Camie screamed. At her scream, the merman finally snapped out of his reverie and glanced over to them. Inasa didn't hesitate, sending a burst of wind towards the mer. Surprised, the mer was shot off the side and fell back into the water, a deadly hiss following his descent. Before he broke the water's surface, everyone except Midoriya saw the look of pure hatred in his eyes before he dove into the depths.

"The merman already sees me and my friends as targets and obstacles for Midoriya-ouji. We have to leave now for attacking him directly." Behind him, his friends agreed. Being vigilant was normal, but mers were tricky beings and it was suspected that several had the means to get on land. Bakugou scoffed.

"Should've gone for the kill, Shit-ketsu." Yoarashi couldn't fault his thinking. He wished he had reacted differently that night. Camie whistled for him to know that their carriage was ready.

"Maybe. It was just chaotic that day. We have to go now. Be safe, ouji-sama." He bowed to the prince, the others following suit. Midoriya nodded to them.

"You too..." The group parted ways and left the Yuuei Knights with their prince watching them leave. Bakugou grumbled as he processed all the information from today in his head.

"Fucking creepy mers."

Let me know what you think! I haven't really attempted something like this before. At least not successfully.