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Strolling through the waters at the beach, Eren Jaeger found himself attracted towards a small, underwater cave, only accessible by swimming under a mountain of rocks. It was a risky operation, but Eren had always considered himself to be daring, always performing dangerous tasks to pull himself away from the “weak Omega” stereotype.
Not thinking too long about it, he decided to go for it, ripping off his shirt and diving into the water. The path was rocky and narrow, almost too small for him to comfortably fit, but there was a sliver of air between the water and the wall, allowing him to catch his breath.
He swam for a long time, limbs becoming sore and exhausted with the strain. Eventually, Eren found himself at an opening, climbing out of the water and sinking on the ground. Gulping for air, he was unaware of the cobalt blue eyes watching his every move.
A splash of water shook him out of his exhaustion as he snapped up into a sitting position. Looking around, he saw that he was in some sort of underground cavity, much larger than the cave he was originally headed towards.
There were small items lying around, and what he could make out to be a bed made of seaweed and blankets in the corner. Eren stared at the bed, completely baffled at how someone could get such nice blankets in the water. How could anyone get here when he struggled so much? Was he even…alone?
Trying not to think of the sudden fear that rang through him, the Omega crawled towards the makeshift bed and laid on it. It was surprisingly comfortable, and even had a pillow under the covers for his head. It didn’t take long for him to fall into an uneasy rest, dreaming of blue waters and slithering creatures coming to eat his toes.
_____________
Soft air on his face slowly disrupted Eren from his slumber, his mind and body becoming more lucid the more he awoke. Opening his eyes, the first thing in his sight was a pale face, dark hair, and long, black horns.
Screaming, he scrambled up and towards the other end of the cave, tripping over the…thing…that disturbed his sleep in the process. Pressing his back onto the wall, the Omega gazed at the one at the opposite end, fully taking in their looks.
Pale skin shined luminously, the dark hair framing the beautifully etched face perfectly. They had a young face, probably younger than him. A sharp nose sat above thin lips that were pursed into a scowl, irritation clear on its features.
Their chest was bare, showing a manly chest, chiseled with abs and strange markings. The lower Eren looked, the more he saw that this person wasn’t human. At their hips were fins that ran all the way down a long tail, twitching in aggression.
The tail was stunning, decorated with stripes and flowers. A chain of weeds sat around the waist, gems and jewels attached to more weeds that hung down the appendage. They were probably the most beautiful person Eren had ever seen, the thought making him sink down onto the ground in awe.
Having heard of mermaids before on television, Eren wasn’t expecting to be face to face with one that looked like it would kill him at any second. He knew he should be worried, as the mere size of the creature was exponentially larger than him. If he stood, they would tower over him by at least twice his height. Their body was wider than his, too, something that sent a jolt of interest through him.
Lost in his thoughts, he was shaken to his core by the sight of the creature slowly moving towards him. Panic rose in his mind again as he tried to make himself as small as possible.
He whimpered in fright as fingers prodded at his skin on his legs. Gazing at the action, he saw sharp nails gently scratching his calf, the sight drawing a squeak from him.
“P-Please d-don’t hurt me! I’m s-sorry for intruding, I-I didn’t mean t-to!”
The creature eyed him for a moment before reaching out and touching his face. It poked at his cheeks and gripped his lips, moving the skin around experimentally as it began speaking, a squeaky (but still much deeper than his) voice ringing through the cave.
“Hmm…humans strangely small. Size of pup. You pup, human?”
At the question, its gaze snapped and locked with Eren’s, his entire body freezing at the contact. Pup? Like a puppy—a dog?
“I-I’m not a dog!”
At this, the creature snorted, shaking its head.
“Not dog, stupid human. Pup. New human. Fresh.”
Eren’s nose scrunched up in confusion. A fresh human? New? Like a…baby?”
“You mean a baby? I’m not a baby!! I’m probably older than you, jerk! I’m fifteen years old.”
The mermaid huffed in irritation as they grabbed Eren in their hands and lifted him like a twig. He was twisted around as the mermaid inspected him closely, moving his body like a rag doll. He was poked and prodded at wherever the fingers could find skin, the mermaid seeming to be especially interested in his toes. The creature even went so far as to rip off his bottoms, leaving him fully naked.
A screech left his lips as the mermaid stroked his bottom, the pad of its finger teasing his hole. Eren began waving his limbs around, trying to escape from his capturer’s clutch.
“HEY!! You can’t touch me there!! And you’re a kid, come on!!”
Eren’s foot connected with the creature’s face, a sharp cry of pain echoing within the walls. He was harshly dropped on the ground as the mermaid grabbed at his injury, staring at him.
When Eren met the gaze of the mermaid, he could only watch as tears filled blue eyes at the pain. He was struck with the sudden pang of guilt as the mermaid turned and shuffled back to its bed, crawling in it and curling into itself.
It was quiet except for a few sniffles. The air was tense and awkward. The guilt only rose within Eren’s chest, and he let out a sign. Cursing his innate kindness, he crawled over to the bed and climbed over the hunking creature.
Settling between the wall and the surprisingly warm body, the Omega began to pry the mermaid’s hands from his face, revealing pinkened skin stained with tear streaks. Sighing, he tentatively lifted his own hand and stroked the soft hair of the creature.
“...sorry for kicking you…I didn’t mean to…”
The creature looked at him, still sniffling. Its finger stroked his nose softly, causing it to scrunch up cutely.
“Bad human.”
Eren scowled at the words.
“Yeah, yeah…bad human, whatever. You really must be young to cry easily like this. How old are you?”
The mermaid grabbed Eren around the hips and flopped onto his back. Eren was forced to lay sprawled out on the firm chest beneath him. He didn’t really know where to put his hands, so he awkwardly flopped them to the side of the creature’s head as it spoke.
“Human bad, bad, bad. Levi not young. Levi older than human in human time. But Levi still child in merpup time. But cause Levi older in human time, Levi in charge of you, now. Little human is Levi’s. Mine now. Be pretty mate and take care of merpups for Levi now.”
Eren’s mouth flew open in shock. This…creature…Levi…wanted him to have his merpups ?? In what world is this even possible?
So lost for words, the Omega’s mouth could only gape open and close multiple times. Levi took advantage of this, moving forward and shoving his lips to Eren’s.
A squeak left Eren’s mouth as Levi’s tongue invaded and stroked his. The mermaid’s tongue was long and slimy, easily soaking his mouth and hitting the back of his throat. He would have gagged, but Levi was oddly strategic about thrusting the appendage so it wouldn’t choke him.
For someone who claimed to be so young in his community, the mermaid was quite adept at using his tongue. He was easily able to coax Eren’s out, wrapping around the much smaller muscle and stroking.
Little moans flew from the Omega’s mouth at the feeling. He was sensitive on his tongue, knowing that from his previous experimenting with some of the boys from school. As embarrassed as he felt about the noises he was making, he couldn’t help the pleasure shooting to his toes.
The tip of Levi’s tongue entered Eren’s mouth as he stroked the appendage. His hand reached out, forcing the Omega’s mouth closed. Eren instinctively knew what to do, sucking the tip genty.
Eren’s moans picked up, becoming louder with each passing moment. His hips thrust against Levi’s stomach, trying to find relief from the growing pleasure. His bare cock stroked against the mermaid’s skin, the tip of his Omegan cock catching with each thrust.
They remained like that for a while, Eren just enjoying the feeling of the pleasure in his little cock. He almost didn’t feel the mermaid’s hand wrapping around his bottom, gently molding it, until a finger traced the line between his cheeks and stroking the slickened rim found there.
Yanking away, the Omega panted heavily, trying to regain his breath. Attempting to pull away, Eren wiggled from Levi’s arms, feeling them close in on him. Hands on the mermaid’s chest, he pushed violently, squeaking out protests.
“W-Wait…wait!! I c-can’t!! It's wrong, p-please!”
In response, he was flipped onto the bed, flat on his stomach. Levi’s weight pressed down on him from above, warming his body. Something wiggly touched his bottom, a shriek leaving his lips. He could feel Levi place his lips next to his ear, panting like an Alpha in rut.
“Bad human, bad mate. Have to make up to Levi. Levi make mate happy, Levi promise.”
The words were spoken between deep growls, the hair on Eren’s body rising. He wasn’t ready to be someone’s mate!! He could barely take care of himself, let alone an Alpha and some pups! He wanted to go home.
“L-Levi! Please let me go home…I’m sorry for disturbing your nest, but I'm too young to have a mate! A-And so are y-you! I’m scared, now, Levi…please let me leave.”
He was turned over on his back as soon as the words left his mouth. Levi looked down at him with an intensely nervous face. Leaning down, the creature gave a little lick to his cheek before nuzzling his face.
“Levi be good mate for pretty human. Levi promise. Levi human no scared. Levi take care.”
With that, the mermaid’s lips were on Eren’s, sliding and licking his way into the Omega’s mouth. Eren had to admit, he had enjoyed the kisses from his experimental endeavours, but they paled in comparison to the way Levi kissed. He threw his entire body into it, the passion coming across beautifully. It was easy for Eren to forget all of his fear, wrapping his arms around the large, firm neck and licking back.
One of Levi’s hands came up to gently fondle the Omega’s cock, his fingers playing with the skin. The pad of his thumb stroked over the sensitive tip, drawing a broken cry from Eren’s mouth.
Levi swallowed each sound that spilled from his lips, his tongue practically down the boy’s throat. It was getting harder for Eren to breathe, and he began pounding on the broad chest.
At the feeling, the mermaid pulled back, scowling down at the human. Eren was breathing raggedly, trying to find his right mind as he stared at the creature.
Taking in the sight of the Omega, Levi grunted, moving down and licking at his chest. His tongue flicked at one of the perked up nipples, feeling the thighs beneath him quivering in pleasure.
Feeling the sudden urge to sink his teeth in something, Levi smiled before biting down on the flesh around the nipple. The boy screamed in pain as blood flooded his mouth. A moan escaped his throat at the taste of his human’s ruby nectar.
Pulling back, Levi lapped at the open wound, smiling for the first time. Eren let out a whimper at the image of daggered teeth, sharpened to the tip. Looking down at his chest, he cried out when he saw the teeth marks on his chest, bleeding profusely.
As he gazed at his wound, sobs escaped his chest, pure fear racing through his veins. Locking eyes with Levi, he could only watch as the mermaid used his sloppy tongue to trail down his body.
Eren’s cock had long since gone soft, but the feeling of the wet appendage on his skin slowly brought his aroused state. He could see his cock trying to get nerd through the pain in his chest.
Levi must have noticed it, as well, since his gaze went straight towards the struggling protrusion. Lowering his head, the mermaid sniffed at it a few times before wrapping his tongue around it, a shrill scream leaving the Omega’s lips.
Hands flying into Levi’s hair, Eren gripped and pulled at the locks as his hips flew towards the mouth around him. He was left breathless as the tongue stroked feverently.
Levi allowed the human to feel the pleasure of his mouth as his fingernails traced the sack hanging below. He was curious about them, not realizing how fragile and tender they were. His nail accidently sliced the thin skin, drawing a screech from Eren.
The sudden pain from having his balls cut drew a sharp throb in Eren’s cock. It hurt, but somehow it only added to the delirious pleasure he was in. His hips were practically slamming into Levi’s face at a ragged speed as his wails reverberated around the cave.
“Ngh…L-Levi!! ‘S good…g-good…”
Suddenly pulling back, Levi sat back on his tail, watching the human flail about as Eren tried to pull him back to his bleeding and throbbing cock. He could see a few nicks from his teeth on the flesh, humming in satisfaction at having thoroughly marked his mate.
Grabbing the flimsy legs, Levi closed them tightly and shoved them towards the boy's chest, putting the puckering hole on full display. He stared curiously at the wetness that leaked from it.
“Human wet why?”
At the question, Eren poked his head from around his legs, ready to tell Levi off. Mouth open to speak, he peaked at the mermaid’s tail, seeing something enormous and dripping poking out from a hidden slit.
Yanking his legs away from Levi’s hands, he sat straight up, just staring at the thing. Taking a hesitant hand, softly touched the top of it, whimpering when he realized what it was.
There was no way that was going inside of him. It wouldn’t fit, and if by some chance it did? It would rip him apart.
Taking advantage of the boy's distraction, Levi grabbed him and laid him on his back. He paid no attention to the indignant yell, only pinning the human down with one hand.
With the other hand, he gripped one of the soft cheeks and moved it, putting the rim on display for him. Bending down, he sniffed at the hole, contemplating its smell. The tip of his tongue slithered out of his mouth, licking around the rim and gathering the liquid there. Pulling back, Levi smacked his lips, swishing the wetness in his mouth. Humming, he savoured the taste as he dove back in to lick at the twitching entrance.
Eren let out a cry at the feeling of his bottom being devoured. He could feel the appendage digging into him, soaking his walls with spit. The Omega’s limbs went numb as they twitched on the ground, his body not able to keep them up.
He hadn’t even had an orgasm and already Levi had worn him out. He wouldn’t be able to take much more of this, that was for sure. Opening his mouth, he tried to make Levi get on with it.
“L-L-ah-Levi!! P-Please…I…I c-can’t take anymore!”
At the words, the mermaid's eyes lifted, gazing at his human. Removing his tongue from inside the boy, he licked his lips. Moving up the thin body, he sank his teeth in different areas on the tan skin, leaving open wounds on the flesh. Blood poured from each bite mark, rubbing between their bodies.
Mouth bloodied, Levi pressed their mouths together as his hands grabbed dainty ankles. Spreading the legs, he settled between them, his huge, slimy cock brushing the twitching hole between Eren’s cheeks.
As their lips swapped reddened spit, the creature’s hips pushed forward, breaching the boy. He knew he was probably too big for his human, but Levi had gone too far to just stop. His pretty human would make the best mother to their pups, and he knew he could make the human happy.
Eren sobbed at the pain of being stretched. Each of his cries were soaked up and swallowed by Levi, who refused to release his mouth. He had no prep from the mermaid, feeling as the engorged cock rubbed against his walls.
Trying to look down around their attached lips and tear streaked eyes, Eren caught a glimpse of his stomach. The skin was stretched where Levi plunged into him, a substantial bulge in its place. The bulge only got bigger and bigger until the creature was fully sheathed in him.
Finally releasing the human’s lips, Levi pulled away, sitting back on his tail and observing their connection. He looked ridiculously pleased with himself as he gazed at his mate.
“Human open up good for Levi. Levi make human feel good.”
As soon as his sentence was finished, he grabbed stretched hips and flipped Eren onto his knees. All he did was swirl the boy on his cock, drawing a squeal from the Omega as something inside him was brushed against.
Once the boy was settled on his hands and weak knees, Levi began to grind his cock inside the clenching walls. The position made it difficult to fully thrust, and Eren seemed to realise that. His hips began to move subconsciously, his Omegan instincts kicking in.
With no sexual experience like this, the human didn’t know if he was doing it right, but he allowed his body to thrust back into Levi. Little moans filled the area as he chased after his orgasm, his pace ragged and rushed.
The mermaid grunted, grabbing the boy’s hips and adjusting him. He brought the human back onto his cock at a steady pace, making sure Eren felt each brush on his tight and warm walls. He continuously hit and stroked the special spot within the Omega, pretty squeaks urging him on as his tiny cock swung beneath him.
“Ngh…Le-Levi!! Please!”
Eren was barely able to form words as he was brutally fucked. His arms collapsed under him and his upper body sank to the ground. His face scraped against the cold, rocky ground as drool pooled beneath his cheek. His eyes were hazy with pleasure and exhaustion as his body was thrust into.
As much as Levi loved being inside his human, he wanted even more to be able to see his pretty face. Once more, he picked the boy up, twisting him and setting the light weighing boy on his lap. His cock was shoved even further inside the human’s guts, brushing everything in there.
Without further ado, Levi bounced the human on his cock, the boy’s limp limbs flailing around. The mermaid’s eyes were glued to the flushed face, watching as his human’s eyes rolled into the back of his head as his cute, little cock sprayed his chest with his release.
Now that the boy had finished, Levi let his own instincts take over. His hands gripped the hips enough that he heard a crack in the bones. He furiously pumped his cock with his human mate, wiggling the tip around inside him so that he could milk the boy’s little dick for each drop it was worth.
Watching his human’s cock and thrusting savagely into him pushed him over the edge. His huge mouth closed around the human’s neck, teeth sinking into the flesh, officially marking the boy as his. His cock swelled up as he came inside the boy, filling him up until the human’s stomach was distended.
It was only their first mating, so the eggs wouldn’t take this time around, but he refused to waste a single drop of their coupling. As he caught his breath, Levi released one side of Eren’s hips and patted the boy’s face a few times.
“Wake human. Wake.”
A groan left Eren’s lips as he was brought back to Earth. His eyes opened, seeing Levi’s face, blood dripping from his mouth. A whimper left his mouth at the sight, tears welling up in his eyes.
He never took his gaze from Levi’s face as the mermaid shifted, moving them towards the makeshift bed. His body was gently laid on the bed as the cock inside of him slipped out, leaving him feeling strangely empty.
Levi moved away from the bed, grabbing something from a little area away from him and moving towards the water. He fiddled there for a moment before returning to Eren’s side, noticing the eyes that followed his every movement.
The creature took the object, which Eren could now see was a cup, and bent it towards his lips. Water dribbled down his chin as he guzzled the water, tasting the saltiness. He gagged, pulling away and spitting the water out.
Turning to glare at the mermaid, he pouted, the facial expression making Levi’s chest swell in happiness at having such a pretty mate. He was glad he didn’t eat the human like he wanted to…the boy was too pretty to pass up.
Ignoring his happy expression, Eren turned onto his side, his body protesting at the motion. His throat was scratchy as he opened his mouth to address the mermaid.
“If you want to keep me, you had better find some water that doesn’t come from the sea, fish dick.”