It was late night when Yuu finally heard the sound of his uncle closing the door of his own room. He waited quietly, curled up under his blankets, listening for any other sounds that Guren might make, but about thirty minutes later the house was completely silent.
He threw his blankets aside and stood up, his bare feet padding quietly on the wooden floor as he went to his closet, opening it and grabbing the backpack he had prepared before going to bed. Throwing it over his shoulder, he padded to the door of his room. He opened it, wincing when it made a cracking sound, but no one seemed to wake up as the house remained silent. Releasing a quiet sigh, he made his way to the kitchen, where he finally grabbed the cupcake he had bought on his way back from school.
He wished he could have bought a cake, but Guren would find it weird to see him coming home with a huge birthday cake. A simple cupcake would have to do, for now at least.
One day, he thought. One day I’ll make a real birthday cake for him .
He checked the clock - 11:23 p.m.
He still had time.
Yuu opened the door of the kitchen, peeking outside. Guren’s house was on a beach, so his backyard was all sand until it reached the sea. As Yuu left, the salt-scented breeze hit him, and he smiled a little, thinking of who he was about to go meet.
Once outside, he didn’t have to worry too much about not making noise. The sand muffled the sound of his steps, so he ran across the beach, the stars and moon being the only things to light his path as he made his way to the huge rocks gathered to the left of the house, where once he explored in search for secret caves when he was only 10, and found a merboy instead.
The rocks were slippery because of the water, so he had to be careful as he climbed them. It was a little difficult finding the right cave in the dark, but as he approached it he heard a soft hum, and his smile widened. He let the melodic voice humming guide his steps, and finally found their secret cave.
The inside of the cave had beautiful crystals on the walls and ceiling that gleamed an eerie green in the dark. Sea water formed a small pool inside of it, with some rocks around, where a beautiful creature sat, humming a song Yuu knew too well. The merboy played with some shells on a collar, his beautiful blue tail half on the water, wavering slightly from side to side creating a soft splash sound on the water. Yuu stopped on the entrance of the cave for a moment, holding his breath as he admired that gorgeous being.
Then the merboy raised his eyes to him, the blue in them gleaming in the dark, and his face lit up.
“Yuu-chan!” He squealed, almost dropping the shell collar he was holding, and his tail splashed harder on the water, like a puppy’s tail when they see their owner. Yuu chuckled and made his way to him, careful with the slippery rocks.
“Hey, Mika.” He said as he finally reached the merboy. As he opened his backpack and grabbed a towel, Mika’s eyes followed his every movements.
“I thought you wouldn’t come.” Mika pouted, watching as Yuu settled the towel on the rocks and sat by his side. “My birthday is almost over.”
Yuu smiled sheepishly, “I’m sorry, I had to wait for Guren to go sleep. But!” He showed Mika the cupcake he had bought. “I brought this for you.”
Mika’s tail once again made that excited wavering, and Yuu giggled as he watched Mika drop the collar in favor of grabbing the cupcake and examine it from every angle possible.
“It’s a cupcake,” Yuu said, “I would bring a real birthday cake for you but…”
“It’s beautiful, Yuu-chan!” Mika sighed, smiling. The cupcake had blue icing with a small blue fondant dolphin. “I’ll keep it forever!”
Yuu snorted and shook his head. “It won’t last forever, Mika. It’s food.”
Mika gave him a puzzled look and glanced at the cupcake, pouting. “It’s too cute to eat, though,” he mumbled.
“I know,” Yuu smiled sadly, “But I can buy another tomorrow, if you want.”
Mika shook his head, “No need, I’m fine with this.” He smiled at Yuu, “Thank you, Yuu-chan. It’s a nice birthday present.”
“That’s not all, though.” Yuu reached into his backpack and pulled out his real present. Mika’s eyes widened and he gasped when he saw it.
“The mysterious globe!” He cried out, almost dropping the cupcake before remembering around it; he set the cupcake on the rocks with his shell collar and reached for the present Yuu was giving him: a small crystal globe with the figure of a mermaid inside.
Mika had found lots of weird stuff that ended up at the bottom of the ocean, and had a huge collection of them that he showed Yuu once (a long story involving a kiss that could make Yuu breath underwater and a long trip to Mika’s lair, a den hidden deep in the sea). He had told Yuu back then that his most prized possession was a “mysterious globe”, a simple christmas globe like those that you shake and small snowflakes fly around inside it; his globe was broken and covered in mud, though, so Yuu had the idea of buying him a new one.
“Did you like it?” Yuu asked, though the answer was obvious by the happy expression on Mika’s face. The merboy hugged the globe and nodded, beaming at Yuu like he had just given him the biggest treasure on earth.
“Yes, I love it! Yuu-chan, you’re the best!” He threw himself at Yuu, pulling him in a tight hug - and when he said tight, he really meant it; Mika had a huge strength, and sometimes he forgot he could easily snap Yuu in two if he so wanted.
“Oof! Thanks, Mika, but you’re gonna break me,” He whined, and Mika quickly pulled away.
Yuu wheezed, trying to get more air in his lungs, and then chuckled.
“I’m glad you like it, though.”
Mika nodded again, looking at his globe with a cute smile. He had changed a lot since they first met, but his smile still remained the most beautiful thing Yuu had ever seen.
Yuu had been 9 when his father went crazy and tried to kill him. After that, his mother committed suicide, and he had spent a whole year in an orphanage before the foster system managed to contact a distant uncle of his, apparently his mother’s brother or something. At 10, he went to live with Guren in a small city by the sea.
On his first day there, Guren had let him go explore the area, and he found these caves near their house. By entering once, he saw Mika for the first time, though back then he was just a boy like him, his fins still small and his teeth not sharp enough. Mika had been terribly scared of him, having heard awful stories of humans, but after seeing Yuu was too young to be of any danger to him, they both became close friends.
Mika then explained to him that he was exploring the surface for the first time, as he had just turned 10, the age the merfolks were finally allowed to go to the upper world. Yuu had become fascinated by the things Mika told him about the underwater world, and in turn Mika was always curious about the human world.
They met whenever possible in that cave, each time bringing each other small trinkets from their own worlds. Yuu had a huge collection of beautiful seashells, of all shapes and colors, that Mika usually brought him; and he had lost the count of the amount of random things Mika asked him to bring, ranging from hairpins to forks and pencils. Yuu found it amusing, but he wasn’t about to complain; Mika always smiled brightly at him whenever he brought him something new.
And now here they were, six years later, on Mika’s 16th birthday. Yuu had been meaning to come meet him all day, but he had been stuck at school and his club activities, and when he got home Guren was there so he couldn’t sneak out without an excuse.
He was finally where he wanted to be, though, so it didn’t matter anymore. Watching Mika’s happy face, Yuu felt more at ease. Mika had grown a lot too, his fins bigger, new scales appearing on his body, and his teeth growing sharper like a shark’s. Still he maintained an eerie beauty, like only a merfolk could, his eyes a curious blue like two precious gems, his hair always silky and soft, his whole frame lithe, though he had some decent muscles that had Yuu drooling.
(Yes, he was attracted to the merboy, what’s new? It’s not like he could help it, with how beautiful and sweet Mika was.)
Yuu supposed he himself had grown decently too, though nothing close to the handsome merboy by his side. He supposed no one could ever compare to a merfolk anyway, but Mika was on another level, he thought. He was just too good-looking to be true.
Mika’s voice snapped him back into reality, and Yuu realized he had been staring too much. He blushed and cleared his throat.
“You were making that cute face again,” Mika giggled. Splash, splash , made his tail on the water. “The one you make when you think too much.”
“Shut up,” Yuu chuckled, bumping his shoulder.
“Oh, I brought you something too!”
That got his attention, and he watched as Mika set his precious new globe on the rocks by his side to grab his shell collar again.
“Here,” Mika offered him the collar, and Yuu noticed his cheeks were flushed a beautiful pink. “This is for you.”
Yuu slowly accepted the collar, sighing in awe. The shells were really beautiful, oddly black, and in between each of them there was a small green shell.
“It’s so beautiful,” Yuu whispered.
“S-so, will you accept it?” Mika asked nervously, and Yuu raised his eyes to him, slightly confused. What was he so nervous about?
“Yeah, of course! Why wouldn’t I?” He smiled. “Though it feels kind of weird having you offer me a present since it’s your birthday.”
Mika fidgetted slightly, sighing.
“Mika?” Yuu gave him a concerned look. “Hey, what’s the problem?”
Mika hesitated, looking from him to the collar.
“It’s… this collar…” He mumbled. “It’s something we do to give to those we choose as our mates. Accepting one means you accept to be my… my mate, so…”
The collar almost slipped from Yuu’s fingers in his shock
“M-mate?” He gasped, blushing furiously. He remembered the kiss Mika had given him a few weeks ago, the kiss that allowed him to breath underwater. When Mika had explained to him how it worked, he had felt really excited because he had wanted to kiss the merboy for years . When Mika finally kissed him, he couldn’t help but feel happy - his lips were so soft, with a slight taste of salt, and Yuu loved all three seconds it lasted.
Only later he had explained to Mika why he had been so embarrassed about it: kissing on the lips, for humans, was something you only did with someone you liked.
“ Like a mate?” Mika had asked, and Yuu had nodded.
Mika had started acting really awkward since then, making him more and more questions randomly about how humans behaved with their mates. Yuu thought he was just curious as always, but now, looking at this seashell collar…
“You… you want me to be your mate?” He asked, and Mika’s shoulders shrunk, his tail waving nervously from side to side. Splash splash splash.
Slowly, timidly, Mika nodded, peeking shyly at him.
“I… I’ll understand if you don’t want to,” He muttered in a miserable tone, “Maybe you’ll prefer a human as a mate, but…” He trailed off, averting his eyes, his expression so sad it broke Yuu’s heart.
Quietly, Yuu put the collar on, enjoying how it felt around his neck and how the seashells sat against his collarbone. He then touched Mika’s cheek, making the merboy look back at him. His blue eyes widened when he saw Yuu with the collar on, but he didn’t have the time to say a word, because Yuu leaned in and pressed his lips against Mika’s.
Mika sighed and then melted into the kiss, placing his hands on Yuu’s face. His palms were cold and wet, the scales on them tickling Yuu’s skin, but he liked it. He liked everything about Mika.
“Yuu-chan…” Mika muttered when he pulled away, and Yuu pressed another quick kiss to his lips before smiling.
“Of course I’ll be your mate,” It’s all I’ve ever wanted . “If you’ll be my boyfriend.”
Mika’s eyes lit up at that. He understood that boyfriend was the equivalent of a human mate - or almost that, now that Yuu thought about it the equivalent would be spouse , but he could explain this later. It didn’t matter to him anyway; he wanted to be with Mika and Mika wanted to be with him, and that was all he cared about. Hell, he’d marry Mika and accept him as his spouse if he had to (though he would have some trouble to explain to his uncle that he had married a merboy at 16).
“I will!” Mika tackled him into a hug again, chuckling, and this time Yuu lost his balance. Both of them tumbled down into the water.
It didn’t matter, though, as Mika was quick to give him the kiss that allowed him to breath underwater - though, this time, the kiss didn’t stop for a long time.