I didn't stop to edit this at all, wrote it late at night while tired and fighting a headache, so I'm sorry for any oddness/if it's not up to my usual quality. Just a quick drabble about a scene I've had in mind for a while.
The first one to hear him was Izumi, entirely by accident. It was late, and they were all inside a Trailmon, most of them sleeping and recovering from their most recent defeat at the hands of the Knights, but Izumi found herself quite suddenly wide awake and unable to slip back into slumber. After a few minutes of shifting about on the bench, she became aware of a sound she hadn't expected - it was quiet, but someone was definitely singing a gentle, soothing melody.
A few quick glances helped her pinpoint the source of the sound as coming from the far side of the train car, where the twins had been sitting - and, sure enough, at a second glance, it became clear to her that Kouichi was still just as awake as she was, and it was his voice she was hearing. Kouji was sound asleep in the corner, and Kouichi was seated with his hands folded neatly, turning the occasional glance to his brother.
With slow, careful movements so as not to make a sound, Izumi crept closer, curious as to what he was singing, but not wanting him to stop. A few steps closer and she realized it was a lullaby, and had to stifle a giggle. Kouji looked the most content she'd ever seen him, and she had little doubt that was thanks to his brother's gentle voice.
He was good, though. His voice was soft and carried the gentle melody with ease, but at times there was a ringing to it that was somehow both haunting and calming. All to soon, though, it ended. Kouji shifted in his sleep, and Kouichi stifled a soft chuckle into his hand. He leaned back in the seat, resting his head against the window for a moment, before stiffening and turning to Izumi, his cheeks turning red. He started to speak, but glanced back at Kouji, and seemed to think better of it, instead standing up and gesturing at Izumi to follow him to another car.
"H-how long were you-?" Kouichi started, trailing off and finding himself unable to maintain eye contact.
With a giggle, Izumi replied, "I woke up and heard you singing. Sorry for not speaking up, I didn't want to interrupt." She leaned over a bit and smiled at him.
Kouichi rubbed the back of his neck and stared at the floor. "Er, um," he said, stumbling over his own words, "I...Kouji looked like he was having trouble sleeping, and, and I...it's just an old lullaby mom used to sing when I...well, she probably did it for both of us at some point, now that I really think about it, but..."
"You're really good, you know that?" Izumi said. She'd meant to make him feel a bit less embarrassed, but the color on his cheeks only got darker.
"Um...t-thanks," he said, shuffling his feet. A moment of silence passed, awkward and heavy, before he spoke again. "We...we should probably try and get some rest," he said. They said their goodnights and headed back to the other car. Izumi still couldn't sleep, but she closed her eyes and got as comfortable as she could. She felt a little bad - she hadn't meant to startle Kouichi like that, and it was obvious he hadn't wanted anyone to know about what he'd been doing.
After about half an hour passed, she heard a gentle melody coming from the other side of the train car again, and smiled.