This is a follow up one shot to "Swamp Dweller" in chapter 33 of this book here, please read them in order ^^

Warnings for: smut towards the end and before the last time skip! Featuring interspecies sex, diphallia, blood during sex (not from penetration but scratching, biting) and general roughness in sex but it's consented, also mentions of mpreg

Also, blood and gore outside of sex but only for a moment, minor character death

******

"Doctor Kim, there you are."

Hongjoong took the hand extended to him, bowing to the assembled committee. Everyone rose briefly for a polite greeting before he was offered a seat at the conference table. It was one of the smaller rooms of Seoul National University, but the group assembled comprised researchers from all sorts of major institutes in Korea and the neighbouring countries.

"It's a pleasure to be working with you," Hongjoong grinned back at them. He sat down to a glass of water and a pristine folder of today's program on the table before him. The person next to him came from Japan and they exchanged hellos in each other's language. Once Hongjoong smoothed out his suit, he lifted his gaze to the presenter who had pulled up a PowerPoint presentation. As all attention gathered on her and the mutters fell quiet, she greeted the room with a professional smile.

"Welcome to Seoul, ladies and gentlemen. Thank you for travelling here today to attend to this meeting. As written in your invitations, today's presentation will focus on recent progresses in the study of indigenous merfolk communities in the area. Since Doctor Kim's breakthrough in the Asmat swamp of Indonesia, our study of this new species has made tremendous progress. Doctor Kim, if you would like to introduce yourself?"

Hongjoong stood dutifully and introduced himself to his fellow researchers.

"I am Doctor Kim Hongjoong from Seoul National University and have been researching the rare swamp specimen we found in the Asmat area. I have led multiple excursions there and am open to your questions."

Courteous applause as he sat down. Hongjoong's research on Seonghwa had been ground-breaking. His articles were featured in academic magazines with great popularity, and he became the sole spokesperson for his niche subject. Seonghwa had become the centrepiece of his work within a heartbeat. Their interest was to explore his differences to other merfolk communities they knew.

"This merman you found is such a rare specimen. The research about him is incredibly valuable. A shame he isn't stable enough to join us at the institute," another man noted. Everyone was so keen in seeing Seonghwa for themselves, no matter all pictures and reports. Since he was Hongjoong's project, they weren't allowed to go to New Guinea themselves to interfere, but they would have loved to bring him to Seoul.

Hongjoong's heart almost broke at the idea of putting him into a sterile pool, so he was against it from the beginning. Seonghwa couldn't communicate yet and he was dangerous even still. If locked up among stone and glass, he would either get aggressive or depressed. Hongjoong couldn't bear removing him from his safe habitat. No matter how often he had to take that long and complicated trip into the swamp, he would rather do that than harm Seonghwa.

"Unfortunately, that's an unwise idea. He is extremely territorial. If he comes here, he might attack us or die of distress. He is most healthy in his natural dwelling," he explained politely, glad to have a say in this matter. His opinion as an expert was valued. Other institutes might have taken Seonghwa away, not caring for the repercussions since he had no community to steal him from.

"As many of them are," the man agreed and the person who had invited them all - the head of Korea's merfolk research foundation - took the word.

"Since you already bonded with him, would you be interested in another expedition? Though he is easiest examined here, we would like to give you all necessary permits and equipment to conduct more research," he offered to Hongjoong, and his heart skipped a beat.

It had been a while since his last trip. Winter came and went and though Indonesia was warm enough that Seonghwa wouldn't hibernate, it was a tough time for his kin when food was scarce and the water cooled down.

He missed his exquisite merman. So he didn't miss a beat with his reply.

"Anytime."

After his first stay about a year ago, Hongjoong visited the swamp three more times. Every time, he came with a team and research to conduct, careful not to impose his personal interests on his work. Seonghwa was open to some language training and taking samples of his blood and scales, but his animalistic instincts were high as ever. While he didn't attack the team, his peace was that of an analytical predator. Hongjoong wasn't scared of him, but he wouldn't claim comfort.

This was an excellent opportunity to return and check on Seonghwa. The days were getting warmer, and he might react positively to some company.

Perhaps one day, he would be ready to deal with humans and a community, but for now, it was best to respect his boundaries and only dare the occasional stay.

When the presentation showed the next slide, Hongjoong leaned his chin against his fingers. The diagrams on display were familiar to him.

"The institute is interested in his mating behaviour. How did he spawn and where is the rest of his tribe? Does he ever leave the swamp to breed with deep-water merfolk and satisfy his urges? We would like you to go on this trip during his mating period and take along one of our female specimens to pair them up. See how the swamp merman courts his female and how they go about reproduction. If you can get some eggs for us to incubate here, all the better. We can study his kind without removing him from his habitat."

It was a regular process, the most humane method of study, without transferring Seonghwa from his home or forcing him through an artificial breeding process.

Nevertheless, Hongjoong's heart was troubled by the idea. Emotionally, he wasn't involved. The merfolk bred with each other as they pleased. It was fascinating to witness, and Hongjoong conducted this research many times. They had some captive-bred merfolk in the institute who were valuable members of the team. Seonghwa, however, was all alone in his surroundings. It might be hard on him. Or, perhaps, a rare chance.

Of course, Hongjoong didn't mention to a single soul what happened between Seonghwa and him. It was relevant only in his own mind space.

But it meant Seonghwa had a breeding instinct and an interest in it as well. So he would be compliant.

It would be the first time he met another of his kin. Even if the mating didn't work out, it would be a fascinating moment to document. Being in his habitat, Seonghwa got to decide for himself what he wanted. Even ignoring the female specimen altogether meant answers.

"I have been meaning to ask Choi San to accompany me as well, see how Seonghwa reacts to males and if they might communicate. If I take him along this time, we can observe whether Seonghwa gets possessive of the female species," he suggested, and everyone around the table agreed.

"Take him along, but install some safety measures for him. Just in case Seonghwa reacts aggressively," was his advice. Hongjoong nodded and took some notes.

"In that case, let's move on to the next topic. Doctor Kim, we will supply you with everything you need. We wish you good luck and look forward to your findings."

Hongjoong's smile was perfect even when he was exhilarated to meet Seonghwa again. To get to introduce him to other merfolk and maybe witness a miracle. He was attached to Seonghwa how an artist was attached to their art. Now it was time to see it flourish.

"I will report back," he promised, and they muttered on about the next topic while Hongjoong prepared himself for the adventure of their first meeting this year.

-

Arranging the expedition took some time. Hongjoong had to organise containers to transport San and the mermaid - a sweet captive-bred member of the institute named Hana - all the way to the swamp. He took his trusty team from last time and even Yeosang joined in again when offered to shoot the rare occasion. Since he made good money from his pictures last time, he was immediately down.

Wooyoung, Hongjoong's colleague at SNU and San's boyfriend, also came along. He was mostly concerned for his lover, but he also offered to help Hongjoong with his examination. They were a bunch of people and the trip took a while, but it was almost like coming home when they made it into the humid jungles of New Guinea.

The Asmat swamp greeted them in its ecological wonders same as they left it. The tide drew over the muddy peat and the orchids were in full bloom, boasting a variety of colours and scents. Yeosang, who had become obsessed with marsupials since their first visit, deeming them 'cute' and 'cuddly' (even those which could claw his face off) shot a few species on their way there.

After setting up camp on the peat and digging a steady mould to put the large water tank containing Hana and San into, the team settled in for the evening. Hongjoong was delighted to be back, and the mosquitos welcomed them with the same cheer. The stench of the rotting swamp was tinted with the sweetness of the orchids, forming a sickening mixture. The humidity clung to their bodies and drenched their skin.

And yet, Hongjoong knew who was waiting for him here. Seonghwa would have missed him as well.

Not even the team knew of their incident. It also never happened again afterwards, and Hongjoong brushed it off as a onetime deal since Seonghwa was overwhelmed and confused by Hongjoong's arrival. Though he had seized Hongjoong's ankle once more during one of the other visits, Hongjoong had withdrawn gently and talked Seonghwa out of it until the intense stare of his eyes redirected to other matters.

He wasn't keen on sharing this very private information, but if it hindered this research program, he would come clean. Sleeping with Seonghwa back then might have shaped his understanding of how mating worked and what he should look out for and do. If Hana couldn't get through to him, Hongjoong might have to sacrifice his pride to write that report.

But for now, they were confident. Hongjoong joined Wooyoung at the water container where San and Hana peered out over the swamp, full of curiosity.

San wasn't captive-hatched, like Hana. He was a deep-sea merman, the predator type with a sharp-edged caudal fin and several scars to boast on his shimmering purple scales. His beauty was eerie and deceptive, like anglerfish in the depths. The black of his hair was inky black and his dark eyes near hollow. They met him during one of their diplomatic visits to his colony and he and Wooyoung hit it off, so he came to the surface to live closer to him since it was more dangerous for Wooyoung to travel to the deep sea than it was for San to hang out in his bathtub. A frightening beauty, not unlike Seonghwa, but he learned human culture and adjusted well.

Hana was his opposite. She was a fresh-water specimen, resembling a gorgeous discus fish with her colourful spottings in orange and yellow. Her fins were dreamy and rippled when she moved, though not as veiled as Seonghwa's. The female body on top was fit and healthy, glowing with her good condition and at a young mating age. Hongjoong got to know her on their trip here and she was kind and curious, ready to figure out the mating process with this strange, scary swamp merman.

When Hongjoong joined their tank to lean next to it by Wooyoung's side, he found their two maritime friends looking out over the lively underbrush of the swamps. The birds called their nightly hoots already, and the water gargled and splashed as animals on the prowl moved through.

"We had been thinking to take a dip to explore but I'm not too fond of those sea snakes," San disclosed to Hongjoong when he noticed their troubled faces.

San dealt with worse, down in the depths, but not Hana. She was sporty, but no fighter.

"It's fine. Other predators respect Seonghwa's territory," Hongjoong assured them. He couldn't wait to see Seonghwa and check how he was doing after the long winter.

Wooyoung had rolled up his sleeves, rather taking the mosquito bites than the unbearable humidity. His dark hair was gathered up into a ponytail as his eyes tracked the curious lizards of the swamp.

They needed to be careful here. A lot of diseases and poisonous plants infested these waters. Even if no animal got their fishy friends sick, their surroundings easily did. Though Hana brushed up on vaccines before coming here.

"Guess we won't go out for a swim until then. There is a colony of reef merfolk near Ewer. Maybe we can visit them on our way back," San suggested, and Hongjoong nodded along. Why not?

Since they had some time, they went over the plan again during dinner. Jongho had set up their technical equipment close enough to the tank that Hana and San could listen in and Mingi - still striving under Hongjoong's wing - heated some ready-made Bibimbap for them.

"We have time to introduce Hana to Seonghwa slowly. See how he reacts when San is nearby and whether he develops an interest. Once his courting behaviour initiates, we take as many notes as we can."

Everyone nodded along, making reminders already about what courting behaviour might appear as and what they had to look out for.

"Since mermaids breed internally, it's important that pregnancy happens only inside you, Hana, and not inside Seonghwa. Even if he is ready and willing, we can't support his pregnancy out here and he might become distressed and kill his young. So make sure it's him entering you."

"Got it," Hana agreed easily. It was odd to tell her this, knowing how Seonghwa mated, but Hongjoong brushed those thoughts off. His help back then had nothing to do with an actual mating cycle.

"We will strap a mic and a radio to you so you can contact us anytime in case of an emergency. There will be cameras, but you can ignore them, the contents are only used for research and your safety," Wooyoung instructed her.

When Hana nodded gravely, ready for the most uncivilised merman she might ever meet, Hongjoong swiped his eyes over the looming mangroves. Something big was moving among them, but their fire kept it away.

"San might be seen as a potential threat to Seonghwa's new mate, or he could become an unexpected friend. We will introduce them gradually. Seonghwa will be territorial and might regard every intruder as a hazard initially. So don't try to be too chummy with him right away."

They had seen the photos of him, read the logs. Seonghwa wasn't the first merman who attacked Hongjoong, but he was the first one who lived in complete isolation and might not even want to consider a community.

But Hana was confident to try it out. Even if Seonghwa shooed them off, that was a result to document.

After finishing their dinner, everyone went to sleep. The tank had a lid for the night and though Wooyoung stayed up long to whisper with San, he soon went to his cot so everyone else could get some rest.

Even so, the first night back in the swamp passed restlessly for Hongjoong. He was too hot from the temperatures and too energetic to meet Seonghwa to get enough proper sleep. Soon, he got up to make breakfast and watched some iguanas chilling on a nearby rock. He kept yawning, his eyes strained, but today was finally the day to see Seonghwa again.

He didn't bring Hana and San along right away. On the first day, it was more important to re-affirm the relationship Seonghwa had with the researchers and make sure they kept his friendship. Wooyoung and Yunho stayed back with Hana and San to get them acquainted with the swamp. Jongho watched over the camp and the other two accompanied Hongjoong.

By canoe, they followed the rivers to the spot they marked on their maps to find back to Seonghwa's hideout. As always, Hongjoong was nervous to return and discover him gone, moved on or ravaged by other predators since he was alone.

But soon, the area cleared of all the wild pigs and crocodiles. Smaller animals were on edge, aware they might be prey in this area. Hongjoong could recognise the familiar landscape of the ever-shifting swamp and his eyes were wide open to find the merman.

As usual, the slick green layer of dirt across the water made it impossible to tell the riverbanks from the swampy ponds. Seonghwa would blend in easily, but Hongjoong came prepared.

The container full of lobsters and crabs and small fishes was the same as the one they used to lure Seonghwa the first time. Perhaps he even recognised the blue plastic that offended his green and brown surroundings by now.

Hongjoong stabilised it with a wall of mud near the water before they retreated further up the hill. This was the same area where Hongjoong once fell into Seonghwa's claws. His cheeks were warm at the reminder, but his two companions were oblivious. Yeosang took a picture of the spider in the tree behind them.

"Think he missed us during the winter?" Mingi pondered as he crouched down, resting his legs from the arduous march through the sticky mud. Hongjoong had him carry their bag with equipment, but realising his exhaustion, he felt bad. On the way back, he would take over.

"Maybe... Let's hope he found enough to eat," Hongjoong hummed. Seonghwa might be desperate for the meal.

Indeed, they didn't have to wait for long. Seonghwa became more trusting with every visit, appearing among the grasses quicker and quicker to throw glimpses at Hongjoong. Now as well, the splash of water stirred the green surface, making the insects twitch and take off when the slime film rippled. The sound was familiar to the team and Hongjoong lifted his gaze, keeping his eyes on their surroundings.

Since Seonghwa knew he was being watched, he would never simply reach for the bait; too wary of a trap. But the next splash drew Hongjoong's attention to a thick bush of overgrown grass. The water stirred behind it, the surface of the green slick broken by a sharp ridge cutting through the surface to disappear into the murky depths.

There he was.

His head emerged first, this time. Peering through a curtain of black hair that clung to his pallid skin. His eyes were vicious as ever, hungry for their prey. When he studied the scientists to assess their danger levels, Hongjoong grinned at the lurking merman.

"Hey, Seonghwa. Do you remember us? We came to visit you."

Yeosang and Mingi wisely stayed behind to document the reunion. When Hongjoong fearlessly stepped across the peat to near the box, Seonghwa dipped. His bony shoulders and the dark green scales of his tail flashed. Soundlessly, he glided over to the riverbank, where his ghostly fingers once more breached the surface.

More of his head peered out, giving away his curiosity as Hongjoong crouched before him with a reassuring grin. Giving Seonghwa the time to get used to him.

"Hello. We are back," he greeted him and Seonghwa was enraptured, much more occupied with his visitors than the fresh meal.

When his lips moved to form words, Hongjoong listened with pricked ears. Seonghwa's voice was rough, every syllable scratchy in his throat since he wasn't used to speaking. But the two sounds were clear enough.

"Hong... Joong..."

Pride swelled in Hongjoong. It took a while to explain to Seonghwa what a name was, and that people used them to call one another. That he was called Seonghwa, and the researcher was Hongjoong.

But he remembered. And the shine in his eyes didn't look too vindictive about being left alone for so long.

"Right, your pronunciation has improved so much," Hongjoong praised him and made a mental note to the cheering and dancing scientist in his mind. Another win to them.

When he held out a hand to caress Seonghwa's face, the merman moved closer cautiously. He stemmed his arms onto the ground, bracing his fingers to lean out of the water. The temperature of his skin was cool as always when Hongjoong tucked the wet strands behind his fin-shaped ear. Seonghwa looked healthy and strong, like the last time he saw him. The winter hadn't worn on him too much.

"Are you doing well? We brought you a snack," Hongjoong smiled at him when Seonghwa's black eyes tracked his expression, every twitch on his features. When Hongjoong beckoned over to the container, he expected Seonghwa to dig in and splatter his chin with blood, but the merman didn't move.

A cold hand wrapped around Hongjoong's ankle. The grip of those webbed fingers was frighteningly strong, Hongjoong knew that best, but Seonghwa wasn't trying to yank him into the water with him. Yet the hold persisted.

Hongjoong searched his eyes. It was impossible to tell the emotions in them since they were so shadowed by hunger and that animalistic insanity Seonghwa still maintained.

With a reassuring hum, Hongjoong pried the grip off without hurting Seonghwa.

"This time, we brought other friends for you to meet. Don't hang out with me too much."

At Seonghwa's persistent stare, Yeosang chuckled near the trees.

"He's pretty attached to you," he noted, taking pictures of their reunion from all angles without getting too close to Seonghwa's hypnotically swishing fin.

Hongjoong sighed. He still hoped he hadn't influenced the merman by accident that night.

"I'm one of the first people he ever met who vaguely resembled him. He's bound to be curious," he brushed it off before he picked up a crab and handed it to Seonghwa directly. This time, he cracked the shell open with his claws to dig his teeth in, trusting the group enough to eat in front of them.

Hongjoong paid him company and reported any outer changes to Mingi. Seonghwa's scales seemed darker after the winter, probably for a lack of light or from hiding in deeper ponds. His ridge and claws needed a trim, but he would do that himself, scratching them on the rough stones underwater.

In all, he was in the best condition to mate with someone. Scary looking, certainly, but healthy and likely near his spring cycle.

When he peered up at Hongjoong as if to interpret his searching gaze, Hongjoong stopped looking him over and smiled back. He beckoned at the crab.

"Enjoy your food," he assured him, and Seonghwa's face was full of fluids when he peered down at his butchered meal.

"F-Food," he muttered, remembering even more. When he made for the container, rancid water splashed up to soak Hongjoong, but he accepted his fate.

Seonghwa rummaged through their catch until he found a fish he liked. Perhaps his favourite taste.

But when he settled back down on his stomach, he held the fish out to Hongjoong. A demand in his eyes.

"Food," he whispered again, hissing with that long tongue and sharp teeth.

Surprised, Hongjoong looked down at his find. Did he want to share it? Or did he prefer it cooked? Hongjoong offered him some of their food while teaching him, and Seonghwa seemed to enjoy it.

"For me?" He asked and Seonghwa nodded, not resuming his meal until Hongjoong took it. And only when he nibbled on the still twitching flesh, pretending to take a bite, Seonghwa sunk back down from his tension, looking satisfied. The fishy stench clogged up Hongjoong's nose, but he was glad to pretend to eat with Seonghwa.

That was a good hint of how to introduce San and Hana to him. Exchanging food as gifts to build a friendship.

Since Hongjoong didn't want to overwhelm him with all the attention, he soon stood so Seonghwa could finish his meal. Mingi had been setting up some cameras, and they finished at the same time.

Their shift had the merman pause once more. Narrow eyes studied Hongjoong's movements.

"We'll come back soon," Hongjoong promised, and Seonghwa understood that. Still, he looked suspicious. Hongjoong said the same when he disappeared for months at a time.

"I promise. Our camp is just over there," he insisted and beckoned in their direction. Seonghwa followed the point of his finger with his eyes, then he stretched out his hand for Hongjoong's.

Trusting, Hongjoong let him draw his fingers to his face even when Mingi sucked in a breath. Seonghwa wasn't moving erratically. Wasn't on the prowl. He merely breathed in Hongjoong's scent, which was so different from anything he knew.

Then he let him go. With one yank, he removed the container from its mould and his spectacular tail splashed as he dragged it into the depths with him. Awed, Hongjoong waited until the water surface smoothed out, leaving no reminder of him.

"Glad to see he's doing well," Mingi commented dryly, even when he was terrified of Seonghwa and would never get too close after feeling his claws once.

Hongjoong also stood and joined them to be on their way back to the camp.

"He's stable enough. Let's introduce San and Hana to him next time," he suggested, and they marched back into the swamp together to get their group ready.

-

San and Hana were soothed by watching the video material of Seonghwa's peaceful reunion with Hongjoong. Hana even cooed about the gesture of handing him food back, deeming Seonghwa capable of instinctual kindness, even outside of a community. They were worried about his lack of speaking ability, but San was confident they could communicate by other means. The deep sea merfolk sung like whales to get their thoughts across and otherwise, dances and gestures worked similar to human sign language and he might understand.

Seonghwa was intelligent. As a predator in the wild and in all cognitive abilities. He learned quickly, even when he was taken over by hunger or desire. Hongjoong wasn't too worried about them.

The next time they went out to meet Seonghwa, they brought San and Hana along. They entered the outskirts of Seonghwa's territory to swim along through the water and Hongjoong kept close on land so Seonghwa would regard them as friends once he spotted them. This time, the whole team went, even Yunho, since he was curious about what would happen.

"How is the water?" Wooyoung asked his boyfriend, ever so concerned about leeches and other parasites after Yunho told him some local horror stories. Wooyoung himself refused to go in the water because of it.

But San swam gracefully, getting acquainted with the animals nearby. Nothing dared too close to his large body.

"It smells different and is murky, like the ocean ground, but it isn't so bad. It's warmer and there is lots of light," he shared and the light also kept Hana sane. Her beautiful scales and fins caught mud in them and might attract crocodiles, but San stuck near her.

Hongjoong fashioned himself a walking stick that doubled as a weapon against curious snakes getting too close to them. He lifted them away on his stick gently, not risking any bites when they made it so far.

Today, finding Seonghwa was harder. He lurked below the surface, mindful of this invasion into his waters. San offered searching for him deeper down, but Hongjoong told him to stay near the surface. If Seonghwa attacked San in the depths, they couldn't help him.

But after an hour or so of sitting on the shore, laughing and eating together, Seonghwa warmed up to their presence and slinked from his hideout. His pale body cut through the water near soundlessly and the beat of his tail was slow, like the slithering of a snake. When his head appeared over the surface, Hongjoong noticed him first. He greeted him with the container refilled. Seonghwa had returned it after he emptied it.

But this time, there was no point in sharing the meal with each other. Hongjoong left the food to Hana and San as he beckoned Seonghwa closer. Everyone kept their posture open and welcoming, hiding the tension behind their stiff features. Jongho and Yunho carried tasers and though they would hate to use them, they couldn't be too sure how Seonghwa would react.

"Come on over. These are the friends I mentioned, San and Hana. Would you like to meet them?"

When Seonghwa hesitantly followed the call of Hongjoong's familiar voice, San and Hana also perked up. Recognition passed between the two parties when Seonghwa realised there were others like him. That he wasn't alone in his peculiar appearance.

His suspicion remained. He didn't get too close, lingering a few paces away to scrutinise the other two merpeople. They were foreign to him, different from Hongjoong and his team. A threat to his territory.

In his caution, his ridge seemed even sharper, the teeth pointier. Every part of him tensed up, watchful to defend his position.

Hongjoong wisely remained in the middle between the parties while his team documented this encounter.

"That's him, right?" Hana made sure, awed by the wild beauty of Seonghwa. Scary as his ridge and his jagged fin may be, the venom, the sharp teeth, he was handsome. Beautiful even, in the sparse light falling through the thick roof of the treetops.

"My, he looks scarier in person," San also commented. He was bigger than Hana, closer in size to Seonghwa and more versed on the scarier variants of their people in the ocean depths. Gender didn't seem to matter to Seonghwa. He regarded them with the same distrust.

"We won't leave you alone with him, Hana, if you don't want to. You have to be confident first. Get acquainted," Hongjoong reassured them. He counted it as a success that Seonghwa didn't launch at them upon the first impression.

When Hongjoong smiled at Seonghwa, his gaze flinched to the researcher. Questioning what this meant.

"Let's be friends, hm? You are lonely out here, especially when I'm not here. These two are like you," Hongjoong tried to explain, showing off San's fin and the webbed fingers.

Seonghwa didn't seem to care about the similarities too much. A subtle snarl tightened his lips, similar to the time Hongjoong's team first encountered him.

"You try to greet him," Hongjoong suggested to San, and he confidently did as told. The water was murky, not allowing much view, but Jongho brought their robotic fish, so they watched on the laptop as San dipped. Nervously, everyone crowded behind the small screen when Seonghwa understood, greeting them below the water.

Seonghwa had no more reason to doubt they were one and the same, breathing through gills, moving their tails. It was no scheme by the scientists.

San clicked his teeth at him, trying some singing and some whistling calls. The clicking seemed to resonate most with Seonghwa, making him perk up and halt in his movements, but he didn't respond.

Hana traced an idle circle around San, brushing her fingers over his shoulders and their tails against each other to show they were close and meant no harm.

Enraptured, Seonghwa stayed to watch them. He even tilted his head, lured in by the friendly sounds and the harmless dancing before him.

Hongjoong chewed on his fingernails. Every fibre of his being hoped they would be friends, despite his prior apprehension. He would be overjoyed if Seonghwa got to enjoy himself with some company.

San offered his hand first. He stretched curious fingers, meaning for Seonghwa to connect with him. Narrow eyes stared back at him. The muscles under Seonghwa's shoulders rippled when he pushed closer, but he was not yet close enough.

Hana also clicked at Seonghwa, her voice even sweeter, the swish of her tail playful and hypnotising with its patterns. Seonghwa came to a standstill, his eyes on her. Measuring her difference to San, her softness and prettiness where San looked more threatening.

Noticing his interest, Hana dared closer, touching one hand to San's outstretched one to extend the other toward Seonghwa. Inviting him to her playful dance, to meaningless circles that meant no danger, just bonding.

Seonghwa moved closer yet, but his hand wavered. He watched as Hana smiled at him and trailed around him at a fair distance, stirring up the water and shining in its murk with her pretty pattern. The long flow of her hair followed her as she twisted her body effortlessly, trailing around Seonghwa in a dance not unlike the male mating patterns.

Fascinated, Seonghwa turned along to watch her. His fin twitched, as if with the instinct to come along.

San kept his distance as Hana convinced Seonghwa slowly. His expression eased, the curiosity in his eyes less guarded. When she extended her hand again, offering to twirl along with her, Seonghwa accepted.

A squeal muffled in Wooyoung's throat and Hongjoong's hands also came up to clutch Mingi's shoulders. Everyone watched with bated breath as their fingertips pressed against each other first, getting used to the feeling. Then, deciding they liked it, their hands hooked into each other as Hana drew closer, coiling her body around Seonghwa's. Scales brushed faintly and Seonghwa looked surprised at the feeling. When her hand glided up his arm, he stretched in her direction, allowing the touch.

His eyes never left her, tracking every single movement. With a shudder, Hongjoong realised he knew that stare. It was the very same. Seonghwa was in the mood. He liked her.

Hana didn't overstep her boundaries. She showed Seonghwa the brilliance of her scales, her graceful movements. All touches were teasing, inviting, but they didn't rile Seonghwa up. He was left curious, wondering, perhaps yearning for more, and it was perfect.

When Hana retreated after a last slow circle around him to return to San's side, Seonghwa also backed away. He needed time to understand this new form of communication, so he disappeared between the plants of the swamp, hiding in his burrow somewhere in the mud.

Hana and San resurfaced, and the team lifted their heads from the stalking fish to their bright grins.

"Date successful," San cheered, and the others lauded them with applause. It took guts to get so close to Seonghwa without showing fear, and Hana did so well. When Hongjoong handed her a drink against the nerves, her eyes were blown wide and her cheeks flushed with a mixture of exhilaration and anxiety.

"You were perfect. He looked so invested," he also confirmed, and Hana blushed, caressing wet hair back over her shoulder.

"I think... I think I like him," she confessed with a shy grin and Hongjoong crouched before her, removing some dead leaves stuck to her hair. She was a beauty, even in the grime of these surroundings, but he looked forward to having her back in the tank where she was comfortable and clean as she was used to.

"You do?"

It was great news. Despite his intimidating behaviour, Hana wanted to indulge in their plans.

"He is so different. So untamed and wild. So gorgeous," she sighed dreamily, reminiscing about his vision and Hongjoong couldn't agree more.

Absolutely, he was. Hongjoong knew best. But he ignored that stab of jealousy since it had no place here. He wasn't special just because Seonghwa tried to mate with him without killing him. He was the first option and now that Seonghwa had more choices; he picked another.

This was perfect for their cause.

A splash of water drew Hongjoong's attention. Seonghwa had resurfaced, back quicker than expected. He lurked with only his eyes out of the water, watching Hana exchange words with Hongjoong. His focus was stuck on her.

So that was that.

Hongjoong smiled at Hana when she also noticed him and shyly cleaned up her appearance.

"Would you like some privacy?" He suggested, since Seonghwa showed no more signs of aggression. The cameras were set, and the camp was close. Though they shouldn't linger at the shore so Seonghwa could mate in peace, the team could take shifts in watching over Hana from the camp in case she needed help.

The flush of her cheeks knew what the next step was, and she looked excited about it.

"Perhaps... He seems willing. I will contact you." When she peered up at Hongjoong, he placed her radio on the peat, along with one of the tasers, in case she needed to defend herself. Not that the gazes between those two called for caution. Their desire was unbridled, instinctive.

"We won't be far."

She knew to cry for help and she swam quickest. A big reason they picked her.

When Hongjoong stood to shoo his team from the waterfront, Hana turned to approach Seonghwa. They disappeared into the water together while the team cleaned up and Wooyoung walked San back to the camp via the rivers.

Perhaps in the next morning, Seonghwa might already be much more comfortable with the team and give San another chance.

Though he would keep his promise and stand watch while he wrote his reports on this marvel, Hongjoong looked forward to this rare friendship and Hana's potential offspring with Seonghwa.

-

Hongjoong stayed up late in case Hana or Seonghwa needed him. Since he was anxious anyway, he readily offered to stay up so his team could sleep. Fuelled on coffee, he huddled under his lamp inside the protective ward of the mosquito net at the tent entrance and scrawled down his musings in his notebook. Hana might not find the way back alone in the dark, so he had his boots at the ready next to his feet, his clothes still on as he waited for her contact.

But the hours passed without any signal. Hongjoong checked the radios were working in between, quietly so as not to wake Mingi in his cot. Everything as it should be. It was a good sign that they spent so long around each other without issues.

The doctor yawned to himself, pondered his bed, then got himself another mug of coffee. He could wake someone else anytime, but he felt responsible. He wanted this to work. Somehow, he was more on edge than ever.

He rubbed his sleepy limbs while he waited for the water to boil, forcing the lethargy away. With his tin cup, he soon returned to his desk. Before he picked up his writing, he checked the cameras in his 20-minute routine.

The grasses hadn't moved, and the water lay still, not giving away what was happening below. Earlier, a lizard slinked past, but that was the most Hongjoong had witnessed ever since he returned to camp.

Now, however, the image was different. Just slightly, probably not noticeable if Hongjoong hadn't studied it so often.

A dark spot had appeared on the shore near the waterline. Hongjoong considered it as an animal, perhaps a fallen leaf. But it looked too dark in the nightvision of the camera.

The shape of it made no sense either. Too angular for nature, yet too blurry to be an object.

Confused, Hongjoong zoomed in, but the picture became too fuzzy.

Torn, he looked between his bed and the screen. He could get cosy and blink the thoughts away, but his only reason for sitting there was to keep watch on anything out of the ordinary.

Perhaps this was the most unordinary thing that would happen tonight.

With a quiet huff, Hongjoong slipped into his shoes and made his way outside. The pitch blackness of the swamp was deafening with all the rustling animals and insects that called over each other. He shone his way across the wet peat, only once near dying of a heart attack, when a giant monitor lizard moved next to him because the light disturbed it.

He made it to the spot without causing too much harm to the animals around him, glad the larger ones shied away from the shine. Only insects gnawed at him and buzzed around the cone of light searching over the riverside.

The dark spot was still there. Hongjoong crouched next to it to shine the flashlight on it and it took him a long, dumb moment to realise what he was looking at.

A shiny red puddle with a radio in it.

Stumped, Hongjoong picked the item up. The red was sticky. Fresh.

Only when the scent of iron invaded his nose, his blood ran cold with the realisation.

What happened?

Within a second, he shot to his feet.

"Hana?!" He called, flicking his beam of light over the tall grasses near the shore, but only other animals replied to him. The water was deceptively quiet, impenetrable to his eyes.

Hongjoong's heart beat in overdrive. Either of them might be hurt. Was this why Hana hadn't contacted him?

"Seonghwa?"

What could it be? Did they get into a fight? Or did an alligator hurt them? Why leave the radio here in such an obvious spot? Hongjoong saw no signs of a struggle at the riverside. No dragging bodies or trails of blood. The radio sat perfectly in the camera shot.

"Where are you?" Worried, he jogged down the stream and back up, trying to spot anything in the darkness.

He needed to wake the others. Needed the robotic fish, needed to search for more clues. Perhaps send San to check on them, even if he interrupted something. This was definitely Hana's radio, and they lost all contact with her.

Just when he spun on his heel to race back to camp, the flash of something red on the bushes drew his attention. His light dashed over, finding more glimmering red peering back at him, attracting insects and lizards.

The grass was tall here, but something had flattened a patch of it out near the riverside. A perfect hideout between land and water.

Hongjoong peered over into the area of broken stalks and his breath got stuck in his throat.

At first, he didn't recognise Hana because she was so full of blood. Her skin and her beautiful scales bathed in it until the pattern swirled into a red mess.

She was gored apart at the entire front, from her human throat down to the middle of her tail. Guts, human and fish, spilled over her sides to become a feast for the nearby critters. Her throat was ripped apart by vicious teeth and her dead eyes stuck in the terror and pain of her last moments.

Hongjoong's knees were made of jelly. He had seen his fair share of gore in his line of work, dissections too. But never had he seen anything so wilfully malicious.

No animal tried to gorge itself on her. All the important pieces were there. She was just ripped apart in the most cruel of ways.

"Hana," Hongjoong whispered and tears stung in his eyes.

This was his fault. He shouldn't have left her alone in this jungle. Too many dangers. Did she try to call for help when she was killed?

Could he have saved her?

The stench was overwhelming, but Hongjoong couldn't just leave her there. He knelt by her side, repulsed by the sight, yet drawn to it by his regret. There was nothing he could fix, all help too late.

Hongjoong's fingers trembled when he reached to unhook his radio from his belt. They needed to bring her back. Turn her remains into an item of science. Honour her by not letting wild animals gorge themselves on her.

The shock robbed him of all other senses. The beat of his heart was quick and loud, frightened in the lonely night smelling of blood.

His perpetrator easily lured him into the snare.

Hongjoong's coarse yell blended with the ever-screaming swamp when a long-fingered hand wrapped around his ankle. The yank was brutal, stronger than any human might be. Within a second, Hongjoong slipped on the wet mud and got a face full of bloodied grass when he slammed down on the soft surface.

He twisted around when the adrenaline rushed into his veins, but he was slow to kick at his attacker. Knew there weren't many who would grab for his ankle in the swamp.

Indeed, it was no snake nor a crocodile.

The light of the fallen flashlight, Seonghwa's face was eerily illuminated. Long shadows clung to his eyes and chin. His lips were pulled back in a snarl, exposing his overly long canines and the blood spotting all over his mouth and throat as if he had bathed in it. The hand around Hongjoong's ankle was clawed, doused in red like the paw of some beast.

He barely looked like himself. His body was too big, the fins sharp like razor blades. The ridge towering from his spine was like that of a dinosaur, broad and jagged, losing his human qualities.

Spooked, Hongjoong lay still for a long moment since he wasn't sure what was going on. He never saw merfolk change their appearance so drastically all of a sudden.

Seonghwa's eyes were black, like marbles. Full of malice and hunger, they shone down at Hongjoong when he yanked at him, drawing him right to the water.

Something wasn't right. Seonghwa didn't look as if he fought a common predator and made it out while Hana got killed. That was her blood on his chin. And his hunger was not yet sated.

Hongjoong wasn't sure if he was out for the same as last time or if he wanted to kill Hongjoong, but he wasn't about to find out. He twisted himself around, reaching for any grass to hold on to, even when it cut into his fingers.

"No- Shit, Seonghwa, let go!" He kicked out in a panic when the grip tightened, almost grinding on his bone. Wet water lapped at his pants as Seonghwa ruthlessly drew him in. A growl came from his bloodied lips when Hongjoong fought against him, futilely squirming towards the nauseating pile of Hana. If he could reach the flashlight...

Cold water engulfed his hips.

"Don't- I can't breathe underwater, let go!" Desperately, Hongjoong tried to kick off his boot and escape, but the grass offered no help. When Seonghwa wrenched at him and his tail splashed through the water with the movement, the blades snapped like paper under Hongjoong's fingers.

His cry bellowed through the forest.

"Seonghwa! Wait-!"

Coldness enveloped him, swallowing him from the waist up to engulf his head. Hongjoong held his breath just in time, struggling against the murky water invading his airways.

Seonghwa was much too fast. With Hongjoong in his arms like a bag of potatoes, he shot through the rivers like a current, bringing the scientist far away from his camp. Hongjoong couldn't see anything, struggling against the hold on him as the pressure on his lungs increased until they were yelling for air. Seonghwa's shoulder was hard, too powerful, no matter how Hongjoong hit his fists against it.

He would pass out soon. It was too much. It hurt. His head throbbed. Plants whipped at him, startling him, and Hongjoong was sure Seonghwa planned to drown and eat him this time.

But then they broke through the water surface. Hongjoong gasped in the precious little air, light-headed from the sudden rush of it. He squirmed weakly, but finally Seonghwa rolled him onto soft sand, out of the cold water.

The humidity was even worse now. Hongjoong was sticky and disgusting and his stomach protested against everything going on right now. When he blinked his eyes open, he was nauseous.

"W-Where are we?" He choked out, not even expecting an answer. He wasn't dead yet. The roots of a mangrove lifted around him, hiding a cave under a roof of vegetation and bushes. Some rays of moonlight filtered through the plants, so they were far out of the swamp. It had to be one of Seonghwa's hideouts when he needed to take a breather above the water. Some bones were strewn about, not all from fishes. It was safe and cosy, but there was also no way out.

As soon as his instincts slammed back into Hongjoong, he startled up from the sand. Seonghwa perched at the only exit through the water. His eyes were wide and hungry, his hands braced against the sand but ready to lunge. His sides quivered with excitement as he breathed in Hongjoong's fear.

When the scientist scrambled away from him as far as he could, a grin dashed over his lips.

Playing with his prey.

"Don't kill me! I'm sorry, I'm sorry... Please," Hongjoong begged. He didn't know what happened. Why Seonghwa did that to Hana and what changed. But Seonghwa was no longer curious and indulgent. The hiss of his voice was that of a predator.

"Hongjoong..." He dragged his body closer, crawling in Hongjoong's direction. In a panic, Hongjoong looked around for a weapon. He lost his taser and the radio during the trip through the water. No branches in his area would snap easily.

Scrambling fingers picked up a bone, praying it would be sharp enough to make Seonghwa hesitate. Not that something so tiny could seriously harm him.

Why did he look so big? So broad? Wasn't he four metres in length last time? The girth of his tail alluded to five now.

"S-Stay away," Hongjoong threatened him and something was deeply wrong here.

This was definitely Seonghwa. No long-lost brother of his. But he wasn't entirely himself. Did he eat something wrong?

When Seonghwa paused to ponder Hongjoong's reaction, the hysterical scientist gagged out as many questions as he could ask.

"You killed her. What's wrong with you? Why do you look so crazed?"

Not that Seonghwa had the capacity to answer, perhaps to even know that information. He only drew closer slowly, steadily.

Hongjoong noticed a pile of rotting crabs and fish in the corner, filling the hideout with the swamp stench. Weren't those the ones Hongjoong caught for him? He recognised some shells. Why hadn't Seonghwa finished them? Did Hongjoong feed him something wrong?

"Please calm down. Let me check on you. Something isn't right," he pleaded, even when he had every right to label Seonghwa a monster and run. Hongjoong wanted to help. He was worried about Seonghwa after all the improvement and patience he exhibited.

In the twilight of the cave, only Seonghwa's massive scale and the darkened hue of his tail were his answer.

"Why did you do that?" Hongjoong tried again, but Seonghwa was no longer in a talking mood. He lurched forward and Hongjoong cried out, but no one would hear him out there. He was a fresh meal, the prey Seonghwa caught so proudly. The bone knocked from his fingers in a second. As he smacked his fists against the heavy body rolling him down to pin him into the ground, Hongjoong did zero damage.

This was it. Teeth to his throat as Seonghwa's wet breath skimmed his neck. Pinned under him with nowhere to go, Hongjoong would end like Hana.

He pinched his eyes shut, trying to brace against the inevitable pain. His trembling fingers on Seonghwa's shoulders failed miserably. Smooth scales skimmed against them as Seonghwa's breath caressed his neck.

Then, with a growl, the merman bucked his hips against Hongjoong.

Within a second, Hongjoong was wide awake. His eyes flew open to take in the same dark cave he had been abducted to.

Not dead.

Like the other time, the very same thing had happened.

Baffled, Hongjoong peered down at the head of black hair that nestled against him. Seonghwa's breath was laboured, as if he was in pain. He squirmed, his tail restless until it could slot into space between Hongjoong's legs. When he felt the human's resistance ease, he breathed a sigh of relief.

Had Hongjoong read the signals so wrong? It would make sense, the change in appearance and behaviour. The raw need while disregarding anything else.

"Is this... Your mating season? Is that why you are so different?" Careful fingers skimmed through Seonghwa's wet hair. His fin shaped ears quivered when a touch caressed them, sensitive to every touch.

Seonghwa must have misunderstood. He thought Hongjoong was giving him gifts again, courting him. That's why he brought back the radio, since Hongjoong accepted it last time.

He didn't understand it was a one-off, what happened between them. Had he desired Hongjoong the entire time, at every visit?

"But Hana... She was right here for you? Why not mate with her? She suits you. She is like you." Wasn't Seonghwa pleased by the invitation? Why rip her apart? Had she hurt him?

Unfortunately, Seonghwa couldn't answer any of his questions. Hongjoong found something so rare here. Relevant data on the first species of merfolk that underwent such drastic changes when their mating season rolled around. Seonghwa's size, the frightening appendages, all meant to trap his mate and have his way with them.

Hongjoong saw nothing like it in other merfolk, so he didn't see it coming. He needed to write this down and test Seonghwa's behaviour, but with the heavy merman on top of him, he wasn't going anywhere.

"Hongjoong... Mine..." Seonghwa growled out, affirming Hongjoong's suspicions.

Hana had been a threat to him. Not the person he wanted for his mating. But Hongjoong needed Seonghwa to understand that they weren't compatible. That this was not the way to treat a human or even a mermaid, since Hana wasn't of the same family as Seonghwa. His human part needed to learn not to act like an animal.

Insistent fingers pushed against Seonghwa's shoulders to roll him off. Another fail. Seonghwa just looked at him from those unreadable eyes. Almost stubborn to stay right where he was, now that he had taken Hongjoong away to be alone.

"I'm- I'm not your mate!" Hongjoong squawked out. Just because Seonghwa chose him and Hongjoong accidentally made himself the person of Seonghwa's affections didn't mean he was safe. Enough fish killed each other during or after mating. With those teeth and claws, his size, Seonghwa could easily rip Hongjoong apart once he had what he wanted. Hongjoong was not about to lose his life in the throes of pleasure.

"Mate..." Seonghwa echoed, pleased with that recurring word even if he didn't know its meaning. He was more mellow now, vulnerable to his needs, but no less dangerous.

Seonghwa wasn't even aware how easily he could kill Hongjoong right now. If something happened, he might be heartbroken but unable to help.

When Hongjoong squirmed again to get away, Seonghwa whined at him. He didn't like Hongjoong refusing him. The hunt was over, Seonghwa won. In his simple mind, Hongjoong had no reason to protest.

Sturdy arms locked around Hongjoong. Hugging him close as if he didn't plan to let Hongjoong go ever again. His ribs protested the tightness of the hug, but he jolted at the skim of soft lips against his throat. So close to death, his pulse hammered like that of a rabbit. Seonghwa could dig into him any second, rip him apart like Hana.

But he was merely curious about the flutter under Hongjoong's skin. Skimming his lips and nose over it, testing his reaction. The shiver trembling down Hongjoong's spine was inevitable. His body remembered their time together, remembered how he liked it. Seonghwa did something awful to Hana, and Hongjoong was cut off from his team, alone and frightened, but the merman hugged him gently. He didn't force Hongjoong while he resisted.

Helpless, Hongjoong pinched his eyes shut. His head was a mess. Fear and fascination swirled into each other, and now his desire clouded a haze around every rational thought.

It wasn't too late. He could still document Seonghwa's breeding behaviour. But for that, he needed to get out of that cave, and he needed more information. Both were easily accessible if only he gave in. Two birds with one stone.

But it was dangerous. Hongjoong didn't want to mistake the tingle of fear with excitement, but they matched awfully well. When he turned his head away to stifle a whimper because his body reacted to Seonghwa's inquisitive caresses, the heat accumulated against Seonghwa's form pressed to his.

How different might it be this time, now that Seonghwa knew what he wanted and followed his instincts? Though that meeting in the swamp had been grimy and unplanned, it was shamefully the best sex Hongjoong ever had and nothing else could measure up to it. His body was already ruined by this wild, beautiful merman. Paired with the treacherous pride of feeling seen, of feeling acknowledged and desired, it was all too easy to give in.

Hongjoong sucked in a breath.

He was really about to do this.

His fingers threaded into Seonghwa's hair, gently pulling him off. Those big, pleading eyes accused Hongjoong of making it harder for both of them. It would have been funny had Seonghwa not killed Hana earlier just to have Hongjoong.

A cruel offer of courtship. Her death was Hongjoong's fault and it would haunt him. But in the most animalistic way, Seonghwa's reaction meant to flatter.

"Okay, slow down. Will you feel better if we do this?" Hongjoong suggested and Seonghwa just stared back at him, reading Hongjoong's body language instead of his words.

Hongjoong bit his lip. He lifted his free hand to trace it over Seonghwa's chest and down to his stomach, making the skin twitch under his touch. Smooth scales blended into human skin as Hongjoong caressed a light touch near the area of Seonghwa's genitals. He watched as long lashes fluttered, a noise escaping Seonghwa's throat as he enjoyed the feeling.

Gorgeous as he was, he was so easy to give in to. Such a scary game to play. Hongjoong was usually more rational, but the fear of death and desire were an addictive mixture. He wanted all of it and if he died; he died in a moment of pure bliss.

Something was very wrong with him since he met Seonghwa and he needed someone to check on his brain.

But first, he needed to get rid of the merman on top of him.

"Do you want me to touch you?" Hongjoong whispered, caressing his fingers over Seonghwa's scalp in a massage. Purring for it, Seonghwa nuzzled into the touch.

"Hngh... Good..." He stuttered and Hongjoong couldn't believe his ears, so proud and baffled how it was only now that Seonghwa dug out his vocab.

"Yes? Good? Can you behave if I help you with your breeding season?" To show what he meant, Hongjoong pressed his body, searching Seonghwa's eyes.

The merman nodded. He understood. He got to do what he wanted if he stopped to listen. And if Hongjoong didn't want this, they wouldn't continue.

Since Seonghwa was so accustomed to his animalistic instincts, it was most fascinating to witness his respect towards his mate. Rape was so common when only the need to mate filled a non-rational brain, but he understood he wouldn't get Hongjoong if he didn't ask for his consent. Or perhaps he just preferred the feeling when Hongjoong participated instead of pushing him away. A certain care and protectiveness over the mate he picked.

Hongjoong needed to write all of this down as soon as he could.

"Alright, come here. Let's do this. You know how," Hongjoong gave in. He only allowed it since they had been here before. Seonghwa let him live once.

Hopefully, he wasn't just thinking with his dick and make it out alive this time as well. Despite the teeth, the unpredictability.

Enthusiastically, Seonghwa wormed his heavy body against Hongjoong's. His tail was partly in the water, but his weight crunched on the sand as he pressed against his small human. Their size difference was almost ridiculous.

Hongjoong didn't think about it too hard.

His trembling fingers unbuttoned his shirt to slip out of it. It was bloodied and muddy, ripped in some places where he dragged against sharp branched, but most of it could be saved. When he exposed his bare skin to Seonghwa, the merman's eyes lit up with a greedy shine. His webbed fingers seized Hongjoong's waist to smooth his nose and lips over his skin, not kissing but breathing in his scent, the taste of his sweat.

Seonghwa's fins quivered by his sides. They flared out, flexing and showing off to appeal Seonghwa's healthy body to Hongjoong. He propositioned himself as a brilliant match to breed with, and Hongjoong rewarded him with a kiss on his forehead as he reached below to see what exactly Seonghwa wanted from him.

Both of his slits had already unveiled with his excitement. The tips of his two penises poked through shyly, not fully unsheathed yet, and his vagina leaked slick fluid. Hongjoong rubbed the small hole gently, making Seonghwa's body shudder and his fin twitch in the water as he pressed into the feeling. The curtain of his dark hair tickled Hongjoong's chest and some venomous spike came dangerously close to his hand, so Hongjoong pulled it back to grab Seonghwa's waist instead, slowly grinding their bodies against each other. Seonghwa's skin was smooth and slick, moisturising itself to offer a confusing yet delightful glide against Hongjoong's chest and hardening nipples.

Seonghwa sighed into the feeling, pleased to have Hongjoong where he wanted. His slick pearled forth, soaking Hongjoong's fingers until the tip of his index easily slipped past the quivering muscle. Seonghwa's cool insides craved touch, fluttering and pulsing around the intrusion. The desperate rock of his hips pushed the finger deeper, but it wasn't enough to please him.

A frustrated groan stifled in Hongjoong's neck. He felt Seonghwa's teeth close, threatening to snap into him and hold him still to chase his pleasure if Hongjoong didn't keep his promise.

"Wait a moment, will you? It will be worth it," Hongjoong scolded him, brows drawn with concentration. He swapped his hands, alternating between Seonghwa's leaking slit and the wet press of his firm cocks pushing insistently against Hongjoong's stomach. Like the rest of him, they were darker, the ridges more pronounced. On one hand, Hongjoong's body heated with the thought of feeling them, on the other hand his rational brain found the idea to even try taking those ludicrous.

But Seonghwa wouldn't budge. He was right where he wanted to be and he was promised release from the strain of his body.

Hongjoong fumbled with his pants to get them off. They got stuck on his knees, Seonghwa's fins and ultimately turned inside out when he finally flung them off his feet, but Seonghwa was thankfully too distracted to complain. He peered down between them to find Hongjoong's erection with his eyes that unfairly saw in the dark. Needy, he ground his slit right down on it, eager to feel it inside. The doctor twitched in response, his tip catching on Seonghwa's rim, and he was not ready.

Hongjoong wasn't carrying condoms. He didn't want to get Seonghwa pregnant, not alone out here in the swamp, even if his body craved for it. But there was no way to get out of his lethal embrace. He might bite Hongjoong's head off if that void wasn't filled, so Hongjoong had no other choice but to comply.

After all of this was over, he could give Seonghwa medication to prevent his pregnancy. Seonghwa had no idea what exactly his body craved and what change it would mean.

"O-Okay, let's do it that way first," Hongjoong gave in. His fingers wrapped around his length, massaging the tip over Seonghwa's fluttering hole to gather up his slick and ease the muscle open. When he finally slipped in, Seonghwa's arms trembled by Hongjoong's head. He reached down to yank the human up against him, forcing him in deeper until Hongjoong almost got a cramp from trying not to come immediately.

"S-Slow-" He stuttered out, suddenly engulfed wholly as Seonghwa sighed blissfully. He rocked his hips down, his fully erect cocks caressing through Hongjoong's cleft. When he wrapped his legs around that slippery body so Seonghwa could sink down on him more comfortably, the weight of his merman on top almost took his breath away.

Trembling from the abrupt pleasure and trying to keep his cool, Hongjoong reached to lather his hand in the slick dripping all over him. He massaged one of Seonghwa's cocks at a time, hand too small to reach around them both. While he was occupied splitting himself open on Hongjoong, the researcher had a moment to push his wet fingers into his own body. Slippery and flexible as Seonghwa had been last time, he looked monstrous now.

His fingers weren't satisfying, too short, too thin, but they were enough to relax his rim and slick it up. Hongjoong shuddered through Seonghwa's shallow thrusts, nudging his dicks into Hongjoong impatiently while he enjoyed the friction of Hongjoong's poor, hard cock inside of him. Every movement seemed ready to snap it off Hongjoong's body for Seonghwa to keep as his trophy. It wasn't made to withstand the tight grip of Seonghwa's anatomy, but it bravely held out.

The scent of the near ocean and Seonghwa's salty musk clouded their hideout. Out here, nobody heard their harsh pants as Hongjoong's body heat turned the cave more and more humid. Breathless lips glided over each other with mismatched hunger.

Hongjoong probably needed more preparation than just three fingers, but his arms ached from the angle and he was too defeated to keep struggling. Exhausted, he pulled back and swiped more slick between his cheeks. Best he could do.

Without pause, Seonghwa immediately rutted into him. He tried to push forth, forcing one tip in and Hongjoong had to reach between them in a panic to keep him from shoving the other right with. Seonghwa panted harshly above him, his drying hair a soft veil over their bodies. Though he only got to put in one at a time, he shuddered in bliss.

It was too much. His dangerous beauty above Hongjoong, the firm massage of his body and now the smooth dick grazing against Hongjoong's prostate. He wouldn't hold out.

His remaining strength went into pushing in a finger next to Seonghwa's girth, easing his entrance further open. He felt the ridges against his fingers, tugging on his walls. Everything between them was wet and Hongjoong was sure they were soaking into the sand beneath to shape his custom grave.

Seonghwa caught his lips, kissing him messily to drink up the moans that finally joined his. They were still preparing, sweaty and strained to make their mismatched bodies work, but they were so close now to getting what each of them wanted.

Hongjoong choked on Seonghwa's long tongue. The canines in Seonghwa's mouth were sharper than usual, cutting at his lip. As Seonghwa lapped up his blood, his moan was most hungry.

The second tip joined into the stretch. Hongjoong held his breath, his belly hot like melted iron and every limb tense. It hurt, not so bad to rip him apart, but he was stretched apart farther than he ever was, much more than regular human sex would ever provide. The ridges nudged into the tight fit, caressing over his rim, his nerve spots, filling him more and more until Hongjoong couldn't even pull off fully and was trapped under Seonghwa's mercy.

No more air reached his lungs as Seonghwa hugged him tightly, pinning Hongjoong's head with webbed fingers to invade his mouth. His heavy tail parting his thighs, keeping him open and accessible to fill him up.

Hongjoong's cry muffled against his lips.

"C-Can't breathe... Seonghwa!" The grip of his insides was so tight, every movement torture on Hongjoong's desperate body.

It was too much. He choked on the lack of oxygen; the sensations washing over him from all sides. Before Seonghwa could as much as buck into him, his orgasm erupted violently, and he spilled inside Seonghwa's heat. His brutal shudder was completely irrelevant beneath Seonghwa and his eyes rolled back as his body convulsed and twitched, stretched open and throbbing around their connected sexes.

But the indignant howl that echoed through the narrow cave was most displeased with the throes of his pleasure.

The sharp pain in his neck had Hongjoong's body lock up, his stomach clutching into a ball of fear. Blood soaked his shoulder and in the first moment, he was so high on pain and pleasure that he thought Seonghwa started eating him chunk by chunk.

But it was only a bite, deeper because of his canines like that of a vampire, but no missing flesh. Seonghwa locked down on him, drinking up his blood while vicious eyes stared at Hongjoong.

"Shit. I'm sorry, I- Oh God, let go." Weak arms pushed on Seonghwa's sides, ever without success. The pain cleared the bliss, and he squirmed, only riling Seonghwa up further as they ground into each other. His growl was a warning.

"I-I'm not going anywhere, okay? Just continue. You can get what you want," Hongjoong winced. Already oversensitive, he knew this would be a long night, but there was nowhere he could flee, anyway.

When he rocked his hips into Seonghwa gently, bringing back the heat in his veins, the merman understood. He kept Hongjoong in a tight lock, suspiciously not letting him run away after having his fill. But the tongue laving over the wound got kinder, and he didn't bite again.

Another minute to live. Not that Hongjoong dared hoping he would make it through the night.

The orgasm helped him relax. When Seonghwa reamed into him, fucking him open with his scary girth to jab pointed tips at spots inside Hongjoong he didn't even know he had, it didn't hurt as much to have his guts jostled about. They found some pace that worked and didn't rob Hongjoong of all breath. With the sand stabbing his back and his fingers guiding Seonghwa's hips, they finally mated in the way Seonghwa needed.

It was graceless and wild, bucking bodies and squelching fluids. Hongjoong's body ached from the pressure on it, but it only fuelled him, finding Seonghwa even more magnificent from the lack of oxygen to feed his brain. It wasn't the worst way to die unless Seonghwa ate him after this.

Hongjoong could just pray that wouldn't happen as he jabbed his tip against Seonghwa's mushy cervix, feeling it soften and ease under the constant pressure. His anatomy allowed the narrow opening to give, kissing at Hongjoong's tip in greeting. Still, same as in humans, the cervix of merfolk wasn't as flexible and smooth as the vagina itself. Its firm fibre locked him with only one path and it was a pain to get through.

Seonghwa's moans had heightened in pitch. He bucked his hips desperately, uncaring about his movement inside Hongjoong so long as he had a body to sheathe himself into. He chased the feeling of Hongjoong opening his cervix oh so slowly and torturously. Pain tightened his brow as he never felt anything like it, but Hongjoong kissed his quivering lips, supporting him as much as he could.

"There you go. Take it slow. I'm right here."

But Seonghwa didn't want to take it slow. He pushed down with a frustrated groan, the channel of his cervix so tight it felt bruising on Hongjoong. Compared to merfolk dicks, his was broader at the tip, more unyielding. It was the sweetest torment to both of them to force it in.

When Hongjoong kissed Seonghwa's chest and his scales to calm him, the merman finally relaxed into the grip enough. Their cries mixed into guttural groans when Hongjoong fully popped through, trapped so only his tip penetrated into Seonghwa's waiting, twitching womb. A rush of ink flooded over Seonghwa's shoulders when he threw back his head and his orgasm struck him immediately.

It was nothing like anything Hongjoong ever felt before. The slot so narrow, so tight. He couldn't even pull out, trapped in the snare of Seonghwa's body. No more friction, no movement. Close to snapping his dick off yet again, Seonghwa's body clamped down on him brutally and though Hongjoong was so concerned about getting his dick back in one piece, the whole meaning of it, the imagination, it was too hot to handle.

Though he already came before, this orgasm felt even more intense. He twitched around Seonghwa's cocks sheathed deep inside him, milking them for their clear liquid that quelled over inside him. In natural exchange, he pumped his own spill into Seonghwa's open womb, more than he thought he could offer on a second round.

Seonghwa's noises sounded euphoric. His claws sliced into Hongjoong's shoulders and down his arms, his teeth bit harshly, but Hongjoong barely felt it. He trembled against Seonghwa, locked in their lethal embrace as their clammy bodies ached with one another.

The moment lasted forever. Hongjoong saw stars where none were. Realised how wet they were because Seonghwa's convulsing tail splashed water all over them. The defensive stance of the merman's spinal ridge had eased, and it drooped with his exhaustion. Blood dripped onto the sand and Hongjoong realised Seonghwa was purring against his chest.

"F-Fuck..." Hongjoong brought out in an awed breath.

He was still alive. His body battered and beaten but miraculously not devoured. Instead, Seonghwa nuzzled into his chest happily, licking up his blood as if it were a treat Hongjoong provided.

Hongjoong knew everything about merfolk mating. Knew how violent it would be and how difficult breeding was between humans and merfolk. This, however, was more savage than anything he knew. Scarily blissful as they teetered on a constant edge of death.

Seonghwa needed rest. He drooped against Hongjoong, absolutely spent, as his cocks shrunk down and curled back into his body naturally. Unfortunately, pulling free wasn't as easy for Hongjoong, but Seonghwa's slick made it work once he got limp. When their bodies finally parted with a wet squelch, Hongjoong breathed a sigh of relief. He felt over his dick and it was bruised, but not sticky with blood or otherwise harmed.

"That was scary," he whispered to Seonghwa as he hugged his arms around his waist, but Seonghwa was mellow, rolling to his side since he no longer had to trap Hongjoong. His body was sated, womb full, and his slit sealed behind his flesh so no drop would escape. When Hongjoong kissed his ear fins and then his cheek, a dopey grin clung to Seonghwa's tired face.

"Get some sleep, hm? I need to treat my wounds before the swamp makes its home," Hongjoong suggested, glad Seonghwa preferred the freshwater and that the entrance to his cave was further away from the muddied vegetation. Not ideal, but Hongjoong could go back to camp after Seonghwa rested for a while.

While his merman snoozed away and purred contently in his sleep, Hongjoong washed out the scratches and ripped apart his shirt as a bandage. The bite in his shoulder was deep and still oozed blood, but he should make it.

While he washed his skin and sipped some of the water from the puddle they travelled through, Hongjoong realised how mad he was. And what he had done, no matter how involuntarily he was dragged there.

He wrung a hand through his hair and peered back at Seonghwa, sprawled out cosily under the dots of moonlight that gleamed on his scales. He has cushioned his head on his arms, looking most innocent in sleep.

Hongjoong would take responsibility for him.

-

"Come on, don't be so difficult now."

Seonghwa whined, his body squirming and tail flicking water at Hongjoong. He was scared of the tiniest needle and Hongjoong had him pinned with arms and legs, trying to insert it into his arm.

Unfortunately, he had brought no pills he could mix into Seonghwa's food. Since Hana was supposed to get pregnant during this trip, they wisely brought levonorgestrel injections to prevent pregnancy in case anything went wrong or she was in pain. They would work on Seonghwa just fine as soon as he let Hongjoong administer them.

"You have to play along so I can get this cleaned up before the team arrives. I do not want to be questioned why I'm doing this and I bet you wouldn't stand up for me either. This entire relationship depends on me," Hongjoong scolded Seonghwa when he twitched away in the last moment once more.

The merman pouted up at him, deeply offended that Hongjoong would try to hurt him after everything they did together. As if the echo of his assault wasn't still throbbing in Hongjoong's shoulders. His wounds were properly bandaged, and he put ointment on them before hiding under a fresh shirt after Seonghwa brought him back earlier, but it would need proper medical care once they were in Agats.

Not as if Seonghwa understood any of this, or what the medication would do to him.

Hongjoong gave him a pass since he was so pretty. He coaxed Seonghwa gently, showing him how tiny the needle was and that it would be fine. Ultimately, he won by kissing Seonghwa and jabbing the injection into his arm blindly while he was distracted.

Seonghwa didn't even notice it.

When all evidence was cleared away and it was just them on the shore, Hongjoong finally breathed a sigh of relief. Earlier, when he snuck into camp, everyone was still sleeping. He would have to come up with a story of breaking the syringe to explain the missing stock. And the team had no idea what happened to Hana yet.

Hongjoong didn't return to the place of gore, but its stench hung heavily over the area. Countless animals found the corpse and gnawed it apart, leaving the stink of guts and blood to rot with the heat.

Poor Hana deserved better. Though merfolk were happy feeding the ecosystem they were born into and lived in, she never got to make a choice whether she wanted this. Once everyone was up, Hongjoong might ask Seonghwa to bring her remains under the water.

Everything about this trip spelled a big red 'fail' stamp on Hongjoong's report. He would have to explain to the institute what happened to Hana, and they might deem Seonghwa as too risky to get near again without weapons.

If only they knew...

After spending some more time with Seonghwa until the effect of the drug kicked in and he got nauseous and drowsy, Hongjoong committed to his duties. He left Seonghwa to nurse his sickness and dragged his hurting body back to their camp to report their failure to save Hana. It was awful news to be greeted with during breakfast, but Hongjoong wasted more than enough time.

When the doctor arrived at the tent with a pained smile, he found Yunho carrying some boxes from the canoe to their cooking place. Mingi and Yeosang made a science out of some eggs and bread there.

"Hongjoong, good morning. I just returned from Agats. The people there were surprised we were back to search for their monster. Told them we tamed it with some fish," Yunho snickered good-naturedly and there was really no way to break this to them kindly.

San was up, peering from the tank. The question lingered on his lips since he had seen which direction Hongjoong came from. Generally, it would be good news that Hana spent the whole night, but Hongjoong didn't look too merry about a success.

"How is Hana doing?" San asked before Hongjoong got to reply to Yunho and his shoulders drooped. This was what everyone looked forward to today.

"I'm afraid I have bad news," he tried to warm them up since people dying on the field was definitely not uncommon. People drowned, people got eaten by sharks, people died of illness from travelling far down into the water.

Still, it was no less devastating. Though they hadn't known Hana for long, her death was cruel and unnecessary. Hongjoong blamed himself for not knowing better.

When everyone stared at Hongjoong expectantly, he exhaled.

"I found her corpse earlier. Seonghwa gored her apart."

Wooyoung sucked in a harsh breath. The rest looked similarly shocked, and San deflated in his tank. His face was the most telling, as if he mulled over the possibility during her long absence as well.

Stressed, Hongjoong ran a hand through his hair. Not all of them were accustomed to this detail of researching a violent species. Mingi felt the same claws graze him before, so he just looked miserable at the thought of what happened to Hana.

Yunho, on the other hand, was entirely foreign to this part of their job.

"What the fuck? What happened? Are you fine? Why did he do that? Damn, that beast is even scarier than I thought." He asked, disturbed by the sudden attack when Seonghwa put up with them so far.

Hongjoong could only offer his prior theories based on Seonghwa's mating behaviour.

"I suppose he felt threatened by her, but wanted to get her alone as soon as we were gone... It was my mistake. I didn't pay enough attention to his body language."

A heavy silence settled between them. Wooyoung's sigh mourned her loss.

"Poor Hana..."

Yeosang crossed his arms. He looked ready to leave after this revelation. After all, who knew if the rest of them were safe? Or when Seonghwa might kill another person to be with his obsession.

"What should we do? Mission failure, yes, but her body? Do I have to document that?"

"I figured bringing her to the water would be best so she can unite with her element. I will send a report to the institute once we are back in Agats. If you can bear it, it would be good to have pictures just in case. Not much left to do an autopsy on," Hongjoong winced, making it sound even worse than it was in their inner eyes.

But Yeosang nodded. That much he was okay with. He could distance himself from the empathy, regard this event as a natural death in the wilderness.

While the others finished the day and got to packing, Hongjoong accompanied Yeosang to the location of the incident and they took pictures of the pitiful remains swarmed by insects and flies. Seonghwa lurked around nearby and Yeosang mentioned how his monstrous features had softened, but he didn't want to stick around. They would be gone by the afternoon, so he went back to camp to help the others clean up.

Hongjoong crouched in the peat for a while, caressing Seonghwa's hair. He was lost in thought about this peculiar bond they formed and how cosy Seonghwa was with him, despite hissing at the other team members.

He was such a special creature. So unique. Hongjoong hated having to leave, but without Hana and after the murder, they couldn't do anything else for now. Seonghwa's mating period ended a success and San wouldn't get anywhere near him to carry an egg.

No, this was another goodbye. And perhaps it was for the better. Seonghwa defended himself and the institute wouldn't try again to have him breed with anyone.

So long as Hongjoong kept their secret safe.

"Time to leave," he sighed, sad that this visit was so marred by blood and pain. He would have loved to play with Seonghwa in the water, feed him and teach him more words, but it would have to wait for later.

When Seonghwa's eyes batted open and his body twisted in a swirl of dainty fins to glare at Hongjoong, he had to snicker. Seonghwa knew so well what this tone meant.

"I know, I know. You are too attached. I will be back. I suppose I have to take care of you now, since this was my mistake in the first place. Maybe I find something to do in Indonesia so I can be closer to you. I'll figure something out."

At least Seonghwa wouldn't get pregnant. One thing Hongjoong did right. (Also yes, his dick still hurt and it was now noon.)

Seonghwa's pout was tinted with frustration. His fingers pawed at Hongjoong's ankles, as if pondering to haul him away again but thinking better of it since Hongjoong was his mate now.

A protective species, noted. Perhaps even one that mated for life.

"Hongjoong... Hongjoong..." He mumbled, but Hongjoong appeased him with a secret kiss, getting to his feet.

"Behave, hm? I'll come back soon," he promised with a light smile, even when the real mayhem was only just beginning once he was back in Seoul.

The researcher left, taking his spooked team and his equipment along. By now, Seonghwa understood when it was time for these longer goodbyes and not just an evening spent alone.

His dark eyes followed his mate through the swamp as he retreated to his work and his mundane life away from Seonghwa.

Perhaps next time, Seonghwa wouldn't let go once his prey was in his grasp.

********

As an info on what happened to Seonghwa: certain species of fish undergo drastic changes in appearance and behaviour when they enter their mating season. Seonghwa's changes were inspired by the male salmon!
Thank our resident expert on merfolk millky_cockk on Twitter for the idea