"When I grow up I'm gonna be your bride, Kaito-nii!"
A tiny three-year-old Len grinned up at Kaito.
"E-eh? Lenny, we're both boys, silly!"
Kaito blushed anyways. "Jeez, what are you saying..."

The tall blunette sighed and licked his ice cream. It had been nearly eleven years since Len made that silly promise. They had been so close then... Of course, as Kaito was now 20 and Len was 14, they rarely had time to talk recently. It was kind of depressing. Kaito stood up and reluctantly put the tub of ice cream away. He pulled on a white jacket and walked out the front door.
As he approached the Kagamine house, Rin darted out, her ribbon bouncing. She grabbed Kaito by his shirt and dragged him away.
"Hey!" the girl that looked so much like her brother said excitedly. Kaito was painfully reminded of Len's similar childlike innocence. "So... me and Len-chans' birthdays are in a few days..." Kaito mentally facepalmed. How could he forget? "...and I want you to come to surprise Lenny! Miku-chan and Meiko-nee and Gakupo-nii will be there too."
"Uh... okay," the older Vocaloid replied stupidly. He smiled a little thinking about how happy Len would be. He was looking forward to seeing the boy, "Kay! See you, Kaito-nii!" Rin beamed. She ran back into her house.
Now left with nothing to do, Kaito wandered around aimlessly wondering if he should get Len a present (completely forgetting Rin, of course). Maybe a banana plushie. He laughed at his own idiotic joke.

"Yay~!" Rin squealed, jumping up and down in excitement. As soon as the candles were blown out, she ripped them out of the cake and grabbed a giant kitchen knife. Kaito shuddered as he remembered her Fear Garden music video. Rin with a knife was generally something to avoid.
"Uhh... Happy birthday, Rin and Len," Kaito said. Rin shoved a piece of cake at him, grinning ear to ear, and Len smiled at him. "Thanks, Kaito-nii~"
Kaito felt his face heat up a little as his younger friend said his name. He quietly nibbled on the cake, wishing he had ice cream too. The room was filled with Vocaloids, gathered to celebrate the twins' birthday.
"So!" Rin said/yelled, wiggling towards her brother. Kaito suddenly realized almost everyone had moved to another room, leaving Rin, Len, Miku and himself. "Lenny! We're fifteen now! Shouldn't you have a giiiirlfriend by now~?" She looked towards Miku with a devilish grin, eyes narrowed. Both the blonde and the teal-haired Vocaloid blushed and looked away. "Kyahaha! How cute you guys are!" Rin made a w face.
"Well you don't have a boyfriend," Len retorted, sticking out his toungue. Rin suddenly stopped her insane laughter, face going blank.
"Actually..." she paused for dramatic effect. The wicked grin slowly returned. "Mikuo asked me out yesterday!" Len crossed his arms and pointedly looked away from his sister. "Well then, since Lenny is being booooring, let's go somewhere else, Miku-chan," Rin said decisively. She took Miku's hand and tugged her away. Miku looked back and smiled at Len apologetically, then followed her friend.
Now left alone with Len, Kaito felt his heart speed up. It thumped loudly against his chest. The blunette wished hard that Len wouldn't be able to tell how unreasonably nervous he was.
"D-do you really like Mi-"
"Kaito-nii." Suddenly Len was standing in front of him. His large ocean-blue eyes looked straight into Kaito's darker blue ones. Kaito felt like he was going to explode. "Miku... is nice and pretty. But I don't like her like that."
"Then who..."
"I made a promise, did I not? A promise to a very, very important person and I don't intend to break it."
"Wha-" Kaito broke off as a jolt of realization ran though him. Len stared him right in the face with a determined, unwavering gaze.
"I-it might be wrong... but... this feeling can't be ignored."
And with that, the blonde stood on his tip-toes and their mouths met. An electric current shot through Kaito and his eyes widened. Slowly, he relaxed and melted into the kiss. He carefully put his hands around the young boy's waist and and pulled him close. Suddenly, Len released and fell backwards.
"L-Len...?" Kaito asked hesitantly. Len looked up, his big eyes starting to tear up.
"That was so freaking embarrassing."
Kaito smiled and gently pulled Len onto his lap. "I bet so. Thank you, though." He rested his head against Len's neck and felt the blonde shiver. "Len... I love you and I'll wait forever, so don't break that promise, okay?" he mumbled. Len made a small noise of agreement and curled up against his six-years-older love.
From the other room, Rin giggled and quietly closed the door.

A/N: AHHH so much dialogue XD More LenKa, yay! I'm not really happy with how this turned out, though...
Thanks for reading this far! =A= If you review I will love you forever and ever and ever.