This is for my good friend Sleepy_Child02. 
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Declaimer: I don't own Digimon or it's characters. They belong to Toei Animation. If I did, I would make Yamchi/Matai and all my other ships in Digimon canon.

This is a tentacle-creature Daisuke x Adventurer Takeru/ Adventurer Yamato x Merman Taichi

??? POV
Watching from the beneath the surface of the water.
A boy with golden-shimmering locks swims overhead, his soft feet padding idly over the water.
Mate. Must make him my mate. The intermittent paddles aligned with the thump of my heart. Ba-dump, Ba-dump. The slim bod slithers, and the abs---mmh! Rock solid. How pretty. I reach out my hand to the blinding light. Pretty mate. Come to me pretty. Come to me.

Adventurer Takeru POV

A chill runs up my spine, an intensifying stare burning holes into my back. I stop splish-splashing around and glance around cautiously. Huh? I take a closer look at the water.

Adventurer Yamato POV

"Takeru, wHaT aRe YoU dOiNg?" Sh*t. My voice cracked. "The ice cream's getting becoming rOoM tEmPeRaTuRe! Hurry up already!"

Adventurer Takeru POV
Hearing my brother's constant "rOoM tEmPeRaTuRe!" calls, I advance onto the sand with confidence. "Yeah, I'm coming!" I glance back once more to the waves engulfing the beach, only to have these dark, mysterious eyes stare thirstily back at me. As if under a trance, I slip back into the water, chin deep, ready to dive in. Glug-glug-glug-glug. An angry hand yanks me out.
Huh? I follow the veiny hand to the man's pissed face.

"Nii-san..."

Adventurer Yamato POV

"What the hell do you think you're doing?" pulling my brother out of the water. I pull him into a hug.

"You could have drowned."
"...." sighing, Takeru's confused face glances back to the ocean.
"Let's go." I lead Takeru away.

??? POV

No. The image of the golden-haired boy slowly fades away. Nononono. Bring him back. He's mine.
Ready to go after my mate, the glimpse of a spike stops me. Oh no.
Blocking the way, a spiky-haired urchin of a merman raises his brow at me.

"Taichi-senpai..."

"Dai," Taichi clicks his tongue, arms crossed. "What are you doing? You know you shouldn't be near the surface, especially with humans in the area"

"But senpai-----"

"No buts!" Taichi's eyes soften

"I just...don't want you to get hurt"

"...."

I twiddle my thumbs, biting my lower lip upon thinking about my mate. My mate, who, just inches close, now feels a thousand miles away. Taichi, although a blockheaded-mess, immediately notices my worry.

"What is it?"

I look up to Taichi's concerned face, a face who I've bawled choking upon the heartbreak of my unrequited crushes. A face who has seen the worst and best of me. A face that I trust. He has always been there for me and look out for me. He look and still takes care of me even when I was kicked out of Atlantis. He came to check on me whenever he could. He brought me food and supplies. He made sure I was well off and the best thing is that he lives at the edge of Atlantis and is not that far away from where I live. He is the simply the best. He defends and doesn't let people talk bad about me.

"I found my mate. I...I felt a connection"

Hand on Daisuke's shoulder, Taichi looks back at the surface. "...Was it one of the humans here?"

"Yeah"

I squeeze my eyes shut, scared to see Taichi's expression. Was it shock? Was it pain? Or was it anger? I scrunch up my shoulders to protect my body, as if expecting a stinging slap to whiplash my face. Getting kicked out of Atlantis for eating the principal's soup was one thing, but loving a human??? That was unheard of, and to its very core, unspeakable. Oh gods, why did it have to be a human. Why couldn't it be a sexy fish? Just wh----"

"You know... you're not the only one who has a human mate." Taichi slides up close and breathes whispers, "I have one too..."

I whip my face to him so fast I feel like I made a sonic-boom. "Really!?"

Shocked and disbelief overcame in a sudden flurry.

"H-have you guys mated yet?"

Taichi looks away, as if reaching for a longing memory, but to no avail.

"Haha, no....it was a long time ago. I-I saved him from drowning. He was such a small boy, and I couldn't just let him drown. So, with all my power, scooped the boy up gently into my arms and swam to the surface. Man, I flapped my fins so hard I thought my tail would fall off. And when I finally broke the surface, I noticed how pale his face was, and realized----his heart stopped."

The words sunk in. No words can describe the anguish in Taichi's eyes. But then the light came back. "But then he began coughing up water, after I...you know" I nodded. Yup, good old CPR. "I was so glad I saved him that I almost burst into tears. And...for some time...we stayed together. Him, making ice cream for me even though he hates sweets, we were happy. But I couldn't stay for long...maybe a few months at most...I had to go back"

"Why didn't you stay?"

"I couldn't---trust me I wanted to but---it was against the rules." Seeing my eyes fall downcast and shoulders droop, Taichi immediately scrambles for a response. Then, pulling out a big grin, and slapping my back with those muscular soccer-trained hands, Taichi cheers on "F*ck those rules! Just go for it Dai. You deserve to be happy"

My eyes spring back up with and my shoulders spiffed up with excitement. Before I even realized it, I was already smiling.

This is why I trust you. You always look out for me and think of what is best for me.

Taichi POV

Smiling softly, I ruffle Davis' soft hair and pluck off the cowlicks of his head.

"From what I believe, there's two humans up there. Siblings, in fact, one older, one younger"

"I'm pretty sure my mate is the younger one"

"Okay, I'll distract the older one while you meet up with your mate"

With the knock of the ultimate bro-fist bump, more bro-er than any other fist bump in the world of bros that peeps be jealous, the two nod in agreement.

"Thank you senpai!"

Taichi POV

"Watch yourself Dai okay and good luck"

Leaving to distract the older male. 15 minutes later I reaches the surface but stays hidden in the shadows. Having a closer look at the older male. Hmmm...he looks a lot like that boy I saved all those years ago.

Yamato POV

Treading upon the sand and OH MY GOSH THE ICE CREAM MELTED, I sigh. Humph! And I kicked the sand into the ocean. Wait...the ocean. I wonder if I'll see him again...that boy who saved me all those years ago. I clench my fist around my necklace, two silver tags dangle from it, one with an orange sun (crest of courage) and the other with the crest of friendship. But this time...I won't let him leave ....this was the other reason why I came with my little brother not just to watch out for him...something tells me he is near...just wait I'll see you again.

Quietly, I begin to set my trap...

Reader POV

"Where the f---- is TK," Yamato murmurs to himself, glaring at the puddle of an ice cream. Curse you, ice cream, curse you and your ability to melt just when I wanted to eat you. Yamato turns away and calls "TAKERUUUU" in increasing volume. Well guess what, I didn't like ice cream anyway. Little did he know that Takeru drifted asleep near the ocean waves, waves that seem so calm and harmless, yet hiding away the roar of a shadow that has yet to reach the shores. KA-CHACK! The trap has gone off

Taichi POV

Struggling within a tangle of ropes, I pry at the frayed edges to pull free. What the hell?! When did this get here!? Flopping about and scrambling to break free using his super-merman strength, cuz no way am I becoming fish meat, a glinting, luminescent shine pulls his attention. A shell. A pickled-plum shell whose sharp edges seems perfect for cutting ropes! I quickly reach out through the holes of the net to grab the shell, straining to grab ahold of it. PLOP! A baby crab pops gingerly out from the warm sand, shaded by the pickled-plum shell on its head. Scuttle, scuttle, scuttle. Aaaaaaaaaaand he's gone. Sh*t.

Reader POV

Meanwhile, Takeru snores peacefully away, unaware of the struggling merman cursing some poor crab who knew nothing better. Cold. A cold hand rests on his cheek, startling, but gentle. Nii-san?... The hand then caresses his face, slowly, and cupped in an endearing manner. Then, the fingertips brush down the sides of his neck, sliding down his collarbone and chest, down... down... and OH MY GOSH HE'S CARESSING MY ABS. Takeru darts his eyes open with a "WHAT THE HECK YAMA----" Takeru's eyes lock with those of a swirled hazelnut color, eyes that peer deeply into one's own with a sense of mystery and piqued interest. Yup, that's totally not Nii-san. "W-who are you?!" Realizing the hand still resting on his abbs, Takeru "eeks!" and the stranger quickly pulls his hand away, disappointingly. Then, pulling Takeru's hand close to the stranger's own chest. "I'm Daisuke"

Takeru, startled from touching Daisuke's bare but sexy chest, reels back. Somehow, hearing the name Daisuke sounded familiar, as if Takeru finally discovered the missing piece to him, an unconscious, connecting thread now becoming more apparent. "I-I'm Takeru." From then on, the two lock eyes with each other in silence, feeling an unnatural force pulling them close together, the force of a red thread binding their souls together.

"W-will you come with me?!" Daisuke blurts out. Takeru, despite meeting a stranger almost blurts out "YES, TAKE ME PLEASE." But he looks back to the melted ice cream bowl.

"I-I would like to....but I can't leave my brother"

Daisuke, taking Takeru's hand, reassures, "It'll only be a while. I'm sure you'll see your brother sooner than you think"

And with a tug of the hand, Takeru follows Daisuke into the water.

Meanwhile, Taichi flounders about in the net.

Crunch. Taichi whips his head towards the sound.

"Who's there! If you wanna make fish meat outta me! I'll ---er -- make sure I'm not delicious!!!!"

"Delicious?"

Taichi freezes at the voice, the low, husky voice that has called out his name in the middle of the night.

"It good to see you, love. I was disappointing that you left without a goodbye"

Red rushes up to Taichi's face from embarrassment and guilt.

"Y-Yamato, I-I-----"

Taichi's tail turns into legs. Oh sh*t

"...So you can live on land, you just can't let water hit you....Why didn't you stay with me? We...we could have started a family, you and I, together with our children. And I always tried my hardest to make sure you stayed, but when I saw the door hanging open, knowing that my lover wasn't coming back, I wondered....did I mean so little to you?" Tears began filling up Yamato's eyes.

"Yamato I!----you know it wouldn't have worked out...I-I...couldn't tie you down to me. A merman and a human? Hah...I had obligations and responsibilities to return to back in the sea world. But I just want you to know.....you meant everything to me."

"..."

"Cut me free Yamato"

Seeing the spiky-haired teen struggle in the net, pitifully entrapped, yet reassuring that he can't escape, Yamato bends down to cut the ropes. Then, pausing with a grim expression, Yamato stands back up."

"....I can't... I-I won't lose you when I found you again"

"Yama!---"