Kaiba entered the basement cautiously, weighing the crown in his hand. He knew that giving this back to the merman would put them on good, solid terms, so it was worth it.

He had had it appraised by a jeweler who had come to his home with all his tools, and declared the value of it to be several million yen.

Also, because it looked like an ancient artifact, the value would only go higher once historians put their bids in, and it took a lot of dexterity to dodge the jeweler's questions.

Atem was asleep, but he heard the door close and ignored it, choosing to stay underwater.

His stomach was pleasantly full and this was the best sleep he had had since his capture.

"Hey!"

Seto Kaiba was calling him from above and Atem continued to ignore him.

Swallowing nervously, Kaiba realized he didn't know the merman's name.

Crap.

Sighing, he walked over to the chair and sat down, making sure to stay several feet away from the edge. If the merman emerged and decided to spit at him…. Kaiba shook his head and propped his head up on the table, closing his eyes and deciding to take a nap.

Atem slowly rose to the surface, making sure to be as quiet as possible. He eyed the businessman, keeping his face beneath the water and inching closer to the edge.

His crown was sitting on the table, right beside the sleeping man's arm, and as promised, all its jewels were intact. It had not been touched at all.

A man of his word, Atem thought appreciatively.

He jumped when the man spoke suddenly, with his eyes still closed. "Hey, fish, what's your name?"

"Fish?" Atem raged, curling his fists at his sides, his cheeks burning. "Call me by my name. I am Atem."

"Okay, Atem," Kaiba said simply, feeling his tongue twist pleasantly around the foreign syllables. He stood quickly and held the crown out to the merman, seeing his own arm shaking slightly.

"I won't hurt you, so you can bring it here," the merman said loftily, smirking evilly at him. "But call me fish one more damn time, Seto Kaiba, and you'll need a new arm, just like that other man."

Kaiba nodded silently and moved closer. The merman snatched the crown from his hands and readily swam away, placing it in the far corner of the pool, out of reach.

Sighing, Kaiba rubbed his aching neck, his eye catching on another pile of sparkling gems gathered in a small pile at the edge.

"More offerings?" Kaiba asked tiredly, and he received a tight nod from the merman.

Atem narrowed his eyes at the human. Was it not clear that he was hurting and missing his family?

"Stop giving them to me," Kaiba said coldly, rising to his feet and moving to sit back in the plastic chair.

There was a long awkward silence before the merman spoke up first.

"You're the first human I've encountered who would refuse these gifts."

"Yeah, well…" Kaiba crossed his legs tightly, giving the merman a quick glance. "They're gems without a serial number, but very clean. I'm not about to be accused for trafficking gems."

Atem blinked rapidly, not understanding a word.

"Nevermind," Kaiba growled, rolling his eyes. The barrage of questions from the jeweler had reminded him to be cautious about accepting gifts that came out of a fantasy creature.

"You either explain, or you don't speak at all," Atem hissed in response, moving closer to the edge and feeling anger spike quickly inside of him. This man was as infuriating as he was handsome!

"Oh my god." Kaiba palmed his face in exasperation. "Humans…we tag our jewels with numbers. Unnumbered jewels are either fake, or stolen—"

"I understand." The merman cut across him rudely. "Your species is so greedy, you must mark every gem with a number so one can claim it."

Kaiba stared at the merman for a long moment before giving him a tight nod. Sure, sure whatever. This thing could understand it in his own way.

"Right, I'm here to ask how you produce the gems in your tears," Kaiba said stiffly, curling his fingers over his knee, and he saw the merman's eyes widen at him.

"I cry," Atem replied stupidly, wondering if the human ever listened to anything he said.

"Yes, but what is in your tears?" Kaiba asked earnestly, leaning forward in his chair. To his dismay, the merman backed away, glaring.

"I don't know, and you're not going to slice open my face to find out."

"I'm not going to do that," Kaiba said quickly, his cheeks reddening with a mixture of rage and embarrassment at the suggestion. Did this merman think he was a monster?

He gazed at the food cart, seeing neatly stacked plates with not a speck of food left behind.

"How did it taste?" Kaiba asked gently, wondering if anything would be considered poisonous to the merman.

"All of it was delicious," came the confident reply, and Kaiba watched the merman swim closer to the edge, looking friendlier. "I enjoyed the varieties of fish eggs you had on the side."

"You have expensive tastes," Kaiba said tersely, thinking of course the mermaid king would love eating all the caviar he had in his private stash.

"Well, I would like more." Atem smiled thinly, glancing at the human before quickly looking away, feeling his cheeks burn with a strange fire again. "Thank you."

Kaiba heard the hostile tone diminishing, and he jumped at the chance to ask, "Can you control the acidity of your saliva?"

Atem blinked rapidly and narrowed his eyes, sinking lower in the water for warmth, wondering if he should answer this question.
It seemed Seto Kaiba had come in to interrogate him on his bodily functions.

"Why do you want to know?" Atem shot back, and to his surprise, Kaiba had a simple answer prepared.

"I'm interested," Kaiba replied, folding his hands together in his lap, gazing deeply into the merman's angular violet eyes, his heart fluttering with nervousness.
This man's eyes were the most beautiful shade of deep violet.

Inhuman, eerie, and beautiful.

"I see." Atem narrowed his eyes at the human, trying to read his aura. It seemed genuine enough, so he decided to answer with, "Yes, I can."

"Yes, how?" Kaiba pressed, leaning forward in his chair, his blue eyes bright with curiosity.

Atem kept his guard up, waiting a heartbeat before answering, "I will it."

There was another long, tense silence before Kaiba nodded, still unsatisfied with the answer.

He was itching to touch the merman's scales and skin, and possibly take a swab of his saliva, but he didn't know how to get close without being attacked.

Baby steps.

First, he had to gain the creature's trust—

"You want to touch me," Atem said nastily, catching a steady stream of thought from the man, and he saw Kaiba stiffen visibly with fear. "And you want to take something called a 'swab', which I assume is a part of me. I'll give it to you, if you bring me two meals a day."

Kaiba felt his eyelid twitch and he remained glued to his seat with shock.
The creature could read his mind.

"Only sometimes, and only when you're feeling vulnerable," Atem said thoughtfully, giving the water a playful flick before adding, "Like now."

Weak all over, Kaiba began to grow numb.
Holy…shit.

He had been right to keep Mokuba away.

"Your next of kin, Mokuba," Atem jeered, leaning over the edge of the water, growing more and more confident with each passing thought. "Cute kid. He gives tidepool demons a good reputation."

Unable to draw his next breath, Kaiba watched Atem lean his head teasingly along the edge of the pool, his beautiful hair spilling over the side.

"I'll tell you what I know, human who deals in business and money," Atem said calmly, holding his hand up and showing the man he could retract his claws to make his hands look as human as possible.

Kaiba bit the inside of his lip so hard, he tasted blood. Before his very eyes, he had watched the claws shrink into the fingers that rounded at the tips.
What the fuck….

"I know that you are scared of me." Atem pressed his chin down atop of his arms and yawned languidly. "Even before you saw me, from the very beginning you were frightened of me. You didn't want anything alive to be in the container. I know. I heard your thoughts."

Kaiba grit his teeth, his face heating up with fury and humiliation.

"True!" Atem let out a deep laugh that echoed pleasantly around the room, and Kaiba felt his skin crawl. "You are a proud man…and…"

And what? Kaiba growled silently, hating the fact that this had turned into an open-session of fortune telling, where this merman picked apart his thoughts and personality, making him feel emotionally defenseless.

"You put up good fight because you're strong-willed," Atem contemplated, twirling a strand of his blonde hair in his fingers, feeling his hand burn from the intensity of Kaiba's eyes following his movements.

"Damn right I am," Kaiba said, and he watched the merman throw his head back and laugh beautifully again.

Enchanted and unable to help himself, Kaiba stared at his slender, tanned neck.

"How fun," Atem smiled impishly and gave the businessman one last apprising look before he heaved himself out of the water and sat enticingly along the edge.

This human wanted to play!

Well, this would be an interesting change of pace.
Perhaps if he got the human to love him, his freedom was closer than he'd originally thought.

Kaiba's mouth steadily grew drier while he watched the merman spread out on the bevel of the shallow pool. His muscles were well-defined and his tanned skin seemed to glow under the low lights.

The sheen in his tail was the most fascinating. It would shift between red and gold every time he moved, and the tips of the tail were sharp and delicate.

"It's been a while since I've played with a human," Atem said smoothly, feeling a small twinge of doubt.

This man would be his first human frolic.
Was this acceptable?

It was forbidden and punishable by death if he, a royal, was caught playing with a human. But there was no one to see them here, and the circumstances were dire.
His freedom depended on it.
Besides, this human was pretty.
There was no harm in trying.

Finally, Kaiba found his voice, and he couldn't speak in a volume higher than a whisper. "What do you mean by play?"

"In all senses of the word," Atem replied calmly, but his heart was pounding so thickly inside his chest, it became a low hum. This human, Seto Kaiba, was a curious one. His actions were not inherently cruel, but just in case a 'swab' was something hostile, he decided to ask.

"But you will have to tell me what a 'swab' is," Atem said deeply, and he watched Kaiba smile prettily and let out a nervous laugh.

"I take a sample of your saliva in a plastic tube, and I get to keep it."

Atem nodded, feeling more at ease now than ever before. He had suspected as much.

Kaiba noticed the nod and his spirits soared. A nod meant that he could take a swab.

Kaiba stared at the merman's bare chest for a long moment before he rose to his feet to hurry out of the room, slamming the door behind him.

Startled, Atem frowned. He hadn't managed to catch the last thread of thought from Kaiba's mind before he ran.

Perhaps he's scared, as he should be, Atem mused, lying back on the cool stone and staring up at the dark ceiling, wishing he could see the sky.
The plan had changed. He would now indulge the human as much as possible, and when the human was satisfied, he would be released.

Human life spans were short, so Atem figured he would be freed within the next fifty years, give or take.

Kaiba leaned heavily against the door, willing his heart to calm down.

He was sweating profusely, lightheaded, and slightly aroused.
Holy fucking shit.
He was being propositioned and…mind-raped.

Was the merman…advancing on him? Hitting on him? Trying to control his actions?

Offering to play.

"In all senses of the word."

Meaning sex! Kaiba thought, horrified, and he sank slowly to the floor in a sitting position. Was he curious about it? S-Sure, but he was more interested in the how, and not the why.

But how could he find out the way mer-people had sex with humans? The mermaid king sure didn't seem like he would willingly offer sex with another human, which probably meant….

It's a trap, Kaiba thought shakily, clasping his hands together and closing his eyes tightly. The merman would catch him off guard then slit his throat. Mokuba would come down and find his bloody body floating in a saltwater pool.

Atem tilted his head, hearing a steady stream of thoughts from the human entering his consciousness, and he suppressed a huff of amusement.
This man was also distrustful it seemed.

The worst and most difficult kind of human to fool, Atem thought angrily, giving his tail an annoyed flick.

So Seto Kaiba would not immediately take him up on the offer. What would he do now?

I'll be here until the end of time, until the end of his time, Atem growled furiously to himself.

After a few short moments, the door swung open again, and Kaiba appeared with a steel briefcase.

Amused, Atem smiled warmly at the human, having changed his tune completely. A pretty human who was mildly frightened of him was better than a pretty human who was cruel and unforgiving.

"We are not going to play," Kaiba said firmly, holding up the bags. "Samples of everything from your body right now."

"Take your time," Atem said mildly, deciding to tuck his hands behind his head and lay back down on the marble bevel. "You can do what you want."

Grinding his teeth, Kaiba set the briefcase down by his feet and flipped it open, revealing rows of empty glass tubes.

"Open your mouth," Kaiba said carefully, approaching the merman with a cotton swab, and the merman obediently opened his mouth wide, showing off a gleaming row of perfectly human teeth.

He hastily stuck the swab into his cheek and sealed it into the tube, his hands shaking terribly.

He snatched up another tube and saw Atem's eyes twinkle playfully at him.

"Venom, from your fangs," Kaiba managed a stiff smile, and the tube was snatched out of his hand. He watched with increasing fascination at the way Atem managed to fit the top fang in through the rim the tube with precision, and a thick, yellow liquid filled it quickly.

Amazing. Simply amazing. In addition to being half-fish, this man was also part snake.

"You think I'm a snake?" Atem asked mildly, listening to the pleasant clinking of tubes coming from the steel box. "I'll show you a snake…."

"I didn't say that," Kaiba responded gruffly, holding up another empty tube and almost dropping it when he saw that an appendage had magically grown from a slit in the merman's fin, several inches beneath his navel.

It was the same color as the tail, but it was odd, slimy…almost tentacle-like but instead of suction pads, there were a series of odd ridges running up and down along its length.

Kaiba sat down hard, and felt his tailbone chafe painfully.
Uh…what the fuck was that?! A worm? A snake?!
An organism that grew out of the merman's tail?
An organism that lived off of the merman's sustenance?
Was that why this man needed so many different nutrients in his water?

Or was that his…penis…

"What?" Atem asked, frowning deeper as he tried to continue deciphering Kaiba's thoughts, which had begun to jumble together incoherently.

"Your pet snake," Kaiba said evenly after finally managing to find his voice, and he couldn't properly draw his next breath.

Atem blinked and wondered if he ought to laugh, his body burning with humiliation. Somehow…again, this human made him feel this way.

"My pet sn—indeed," Atem replied, his voice shaking with mirth. "Would you like to pet him?"
This human was truly dense! Was he doing it on purpose?

Kaiba gripped the glass tube so hard, he felt it almost shatter in his grasp.
It was his penis.
This had taken a strange turn.
And the merman was making fun of him.

"I see, that is the word for it," Atem smiled sweetly, wondering if he had scared the human sufficiently enough. "Is it true that you humans like to give it a name?"

Completely at a loss for words, Kaiba shakily replaced the empty tube back into the briefcase and stared a blank space on the ground until his eyes began to water.

Incredible.
A male merman was propositioning him.
Hell…fucking no.
He wasn't gay, at least he didn't think so.

…But how could he say 'no' for an opportunity to take to a sample of a mythical creature's semen?

"You want a sample of…what?" Atem asked shrewdly, losing his patience as his arousal began to fade into disappointment. "I thought you wanted to play. It seems you are cowardly after all."

Kaiba blinked rapidly, wondering if he ought to take the bait. The merman sounded impatient and angry.

"Show me how you touch it then," Kaiba said headily, turning slowly to face Atem, and he crossed his legs firmly, feeling the wetness from the ground soaking in through the bottom of his trousers.

Atem blinked once and nodded slowly, curling his fingers around his own shaft. He gave himself a steady stroke upwards, enjoying a warm jolt of pleasure traveling up through his stomach, understanding that Kaiba needed some guidance.

Kaiba felt his head spin violently as he watched Atem's fingers stroke the odd-looking tentacle, his knuckles whitening over the shaft which had begun to stand up and look somewhat erect.

Was it…not going to stay erect?
Deeply aroused and intrigued, Kaiba continued to watch, noticing that the tip would flick this way and that after a particularly pleasurable stroke upwards, and he swallowed thickly, shifting uncomfortably while his back was drenched in nervous sweat.

Oh…man. This was fucking weird!

"Let go of it," Kaiba said quietly, his curiosity rising to an all-time high, and his stomach tightened strangely when the merman threw him a playful smirk and released his shaft slowly.

He watched in amazement as the tentacle curled over Atem's thumb almost longingly before the hand was withdrawn, and Kaiba felt a strange pressure in his groin when he had a sudden image of the length inside his mouth.

The tip was pointed almost like a tongue, and if he ignored the fact that it was coming out a gigantic merman's tail, and only focused his gaze on the merman from the torso up…would it be like sucking on a giant tongue?

No longer able to string together a coherent thought, Kaiba reached for it and almost recoiled when the tentacle seemed to reciprocate and stretch towards his hand eagerly.

"Stop that! Are you doing that?" Kaiba cried, shrinking his hand away quickly, his heart thudding painfully in his throat as Atem let out another deep laugh.

"No…only sometimes," Atem replied excitedly, pleased with the human's reactions. They were so interesting!
He could see why playing with a human was something mer-people enjoyed. The mere reaction was worth it.

Taking a deep shaking breath, Kaiba reached for it again and saw it straining toward his hand once more. Oh god…gross….!

A human penis was strange enough, but this thing….!

Kaiba reminded himself to shut up because the creature could read his mind, and he bravely wrapped his fingers around the length, expecting it to be cold, but it was warm.

To his utmost horror, the tentacle jumped excitedly up in his hand, and Atem's chest heaved with excitement as he threw his head back, enjoying the foreign sensation of heat consuming his body.

"Oh my...g—holy…s—," Unable to properly talk, Kaiba kept his hand outstretched over the tentacle and splayed his fingers out, watching it writhe excitedly around his palm in a mesmerizing dance, slipping in and out through the gaps of his fingers, almost as if it was a tongue, licking his hand, waiting for it to grasp onto it tightly.

Letting his breath out slowly, Kaiba gave it a firm grip and a few rough strokes upwards, seeing the merman's tail convulse suddenly while Atem let out a shuddering gasp. "Too much…don't!"

Slowing his motions down, Kaiba ran his hand up and down along the full length, fascinated with how it self-lubricated at the base and extended fully when he pulled it upwards. The more he thought about it, the more it was just like a giant tongue.

His dick leaked wetly in his underwear, startling him greatly, and Kaiba froze, realizing that he was aroused by this…by some strange miracle, or curse.

He gave Atem a nervous stare, seeing the merman's eyes half-lidded with lust and his mouth parted excitedly.

A kiss with that acidic saliva would probably kill him, but kissing this thing down here probably wouldn't kill him.

"Stop thinking about that," Atem commanded, breathing heavily and deeply excited. "I've decided I won't kill you. You're too entertaining for that."

Kaiba was only half-listening. His ears were ringing with a strange noise and something possessed him to lean his head down to give the pink tip a quick sniff.

It was an oddly fresh scent, reminiscent of an ocean spray mixed in with something…unique.

Atem gasped and almost recoiled, drawing his tail up to his chest. Was the human going to bite him there?! It wasn't for eating!

"Stop," Kaiba mumbled, now fully intending on sucking the merman off. "I'm going to lick it."

Horrified, Atem shook his head frantically, thoroughly regretting everything now.

The human pushed the middle of his tail down with surprising force, causing him to lay flat, and before Atem could compose himself or protest again, a hot, pleasurable warmth consumed him steadily, and he glanced down at himself breathlessly, unable to tear his gaze away from the strange sight.

The human had captured his length inside his mouth and was sucking powerfully, sending more violent jolts of pleasure running up and down his spine, and Atem let out a frantic gasp as wave after wave of alien sensations washed over him.

Meanwhile, Kaiba was conflicted, half-enjoying the way Atem's penis moved freely inside him like a tongue swirling happily against the roof of his mouth, and half-regretting ever putting his mouth on the wriggling length, because the taste was extremely salty, and it was so thick, his jaw was aching.

The tip of the tentacle snaked upwards naughtily, almost as if teasing him, testing him, challenging him to take it deeper into his mouth, so he did, pressing his palms down on either side of the merman's scaly hips and letting the tentacle dick shoot upwards repeatedly past his own tongue and pleasurably hit the back of his throat with surprising strength.
Oh…holy fuck.
What if this thing moved like this while it was inside of him?
Or even…on his own penis, while Atem thrust his hips upwards?

The rigorous up and down motions of the tentacle inside his mouth was already lewd enough, causing his stomach to churn with a mixture of ecstasy and arousal. His pants were uncomfortably tight, and Kaiba wished he could touch himself while this odd penis fucked him in the mouth, but he held back.

Atem's vision was swimming dangerously in and out of focus as the human's mouth would not let up. Sometimes, there would be a powerful suck, sending an enormous stream of heat down to the very tips of his fins, and other times the light bobbing of Kaiba's head sent tingles down his fingertips.
Amazing. Never in all of his life had Atem ever felt such intense pleasure.
Humans were filthy creatures because of their knowledge of this act.

Unable to hold out any longer, Atem gave in to the repeated swirls and strokes of heat and let out a shuddering sigh, releasing thickly into Kaiba's mouth.

"Shit!" Kaiba jerked his head up frantically and dove for his briefcase, snatching a glass tube with a slippery hand and managing to scoop a residual glob of semen into it.

Shaking with adrenaline, he gazed at the wet and sticky mess covering Atem's tanned torso, actively avoiding looking at the wriggling tentacle still jumping excitedly upwards from his groin.

Kaiba lips dryly, tasting nothing but the strange tang mixed in with salt.

He was glad the color of semen was also white, but…was the sample contaminated with his own saliva?

Sitting back on his heels, Kaiba forced himself to calm down, willing his boner away. That had been fucking weird, and he had possibly crossed a line.

Atem let out a contented sigh and glanced down at himself curiously, his heart still racing madly inside his chest, his body still shaking with threads of residual pleasure.

That had been…too short, and too intense.

"...Again?" Atem ventured weakly, hearing his own voice shake. He was beginning to understand now why playing with humans was explicitly forbidden.
He never wanted to even think about another mermaid ever again!
If a human's mouth felt this good…it meant that other parts of their body might feel even more amazing, indescribable even!

"Again?!" Kaiba gasped. The slime had not yet dried off his own hands, and he wondered if he ought to wipe it on his own pants, or wash it off in the pool. Was the semen acidic too?

"Yes, it was quite good. Again," Atem said simply, giving the human a smile, feeling newfound appreciation for Seto Kaiba.

"Right-right now…?" Kaiba blinked, deeply shaken, and the merman nodded his spiky head firmly with another playful smile.

"You don't want to?" Atem tilted his head at Kaiba, gazing hopefully into his clear blue eyes, feeling his heart skip several excited beats inside his chest.

There was a long silence.

Kaiba slowly reached to snap his briefcase shut before rising to his feet unsteadily.

He stumbled to the exit, ignoring Atem's calls echoing from behind him.

"Human…come back! Are you tired? Or is it true that you can only go once?"

Kaiba slammed the door behind himself and leaned against it heavily, his breathing ragged.

Holy fuck.

His dick hurt from staying resolutely hard inside his pants, and Kaiba cursed himself darkly.
Was he seriously going to jerk himself off after doing that?

He had just mindlessly sucked on the merman's tongue-penis.

And it had felt good.

It had felt really good.

The thought of how Atem's tongue had danced erotically inside his mouth was enough to make him cum, and grit Kaiba his teeth, curling his knees to his chest, rocking back and forth steadily, riding out his low orgasm.

And that was another first.
He had somehow managed to cum inside his own pants without a stroking touch, and with just pure thought.

Maybe I've been possessed, Kaiba thought glumly, his mind humming with a strange haze he recognized as lust.

But a tiny voice in the back of his mind told him that he had done everything of his own accord, because he had wanted to lick the merman's strange dick.

Slowly rising to his feet, Kaiba left the briefcase on the floor and made his way to the elevator, deciding to take a cold shower.

Inside the room, Atem slid back into the water smoothly and floated blissfully on his back, his mind wonderfully clear, his body strangely light.

That was something he could do all day and all night. It was understandable why many a mermaid would run off with a human man who could give them that kind of pleasure, but mating with humans would ultimately lead to their extinction.

I'm in trouble, Atem thought guiltily, throwing a hand over his forehead, feeling himself grow aroused again.

At this rate, he wasn't sure how many times he needed to copulate with the human before he felt completely satisfied.

Something that had been a teasing hunch had turned into a serious pleasure session, and Atem's mind kept wandering back to the way Seto Kaiba kept his mouth clamped tightly over his entire length.

Shaking his head firmly, he forced the image out of his mind and flipped over onto his stomach, staring down at the white floor at the bottom of the pool.

One thing was for certain. Seto Kaiba was an amazing human in more ways than one.

Author's note:

Kaiba grapples with his sexuality and then feels horrified at what he did.
Atem is literally just so happy and horny, he just wants to go again and again.
The forbidden fruit is always the tastiest.
Might as well make the most of your imprisonment, right?

edited by: setokaibaes