Same universe, but not Canon. Jack is 18, Kalin will be turning 19, Crow is also 18, but younger than Jack, and Yusei is 16. No idea what age they are in the actual show. Anime is weird like that.
Jack scoffed at one of Crow's comments as he pushed the door open.
"Oy! Kalin!" he barked.
Crow shoved past him. "Hey Kalin! Ya here?"
Crow ducked into the kitchen and Jack headed for the living room. Striding across the darkened room, Jack paused, eyes catching on the dark bundle of limbs and spiky hair tucked into the corner of an old armchair. Stepping closer, he made out black hair with gold streaks standing up at all angles, oversized clothing, and the slight rise and fall of the small male's chest as he breathed. Blinking in surprise, he stared for another moment before continuing down the hall to where Crow was noisily rousting Kalin from his sleep.
Kalin yawned and stretched as Jack came in. Couldn't they have let him sleep? "Seriously you guys? It's like 7am!"
Crow snickered. "It's almost noon."
Kalin gawked for a moment, snapping out of his surprise at Jack's sudden question.
"Who's your roommate?"
"Roommate?" squawked Crow. "You've got a roommate and you didn't tell me?" he accused. "Is it a guy or a girl? How'd you meet? Can I meet them? What are they like? Are you close?"
"Whoaaa, slow down Crow," chuckled Kalin. "It's a guy. His name is Yusei, and we're not super close yet. I only met him a couple of days ago and he needed a decent place to stay. Apparently he was on his own, but the place he was holed up in didn't have running water or electricity. Not all that uncommon here in the Satellite, but impressive considering how long he's been on his own."
Crow blinked curiously, opening his mouth for another question before he was cut off by Jack. "He's wearing your clothes. You never let anyone wear your clothes."
Kalin sighed. Jack was never one for small talk.
Crow piped up again. "What!?" he hollered. "I thought I was your best friend!"
"Of course not, you dolt, I am," dismissed Jack.
"What was that you-"
"Kalin?" interrupted a sleepy voice from down the hallway, a bit confused.
"Yup, and two more," he answered, quickly moving past the silenced pair.
"Friends of yours?"
"More like brothers," Kalin answered with a laugh. He reached forward, ruffling unruly gold-on-black spikes. "Fall asleep on the couch again?"
"No, the armchair this time," Yusei sighed, chuckling a bit.
"That's a guy?" asked Crow incredulously.
Jack smacked him upside the head. "Have a little tact."
Yusei yawned again, reopening slightly cloudy cobalt orbs. "If I wasn't so tired, I'd hurt you," he threatened ineffectively.
"Jack, Crow, go back to the living room," Kalin ordered in frustration. "You're blocking the hall. I'll be there in a minute."
The two did as told, watching Kalin lead a sleepy Yusei by the hand. "You should really work on making it to the bed," laughed Kalin, half-serious.
"I tried," the raven defended. "I couldn't remember which one was mine. You've got like 3 bedrooms!" He sounded embarrassed.
"You'll get it," reassured Kalin. "But later," he amended. "You should get some sleep in an actual bed first."
The voices trailed off down the hallway as the two disappeared into one of said bedrooms.
Jack and Crow waited in the living room for Kalin to come and explain, knowing he wouldn't leave them there for long. Said male popped into the room a couple of minutes later.
"First things first," he warned, "don't prank him."
Crow blinked, surprised by his seriousness. "Why not?"
Kalin narrowed his eyes, sensing the coming defiance. "Don't," he repeated. "He's blind."
Crow lurched, unsure he'd heard right. "Really?"
"Yes, and he hadn't really had a chance to settle down here yet, either. Give him a chance to get used to us before you start messing around. I don't want him to get hurt and he seems pretty skittish."
Crow seemed to do an immediate about face. "I don't prank people with handicaps," he promised solemnly.
Kalin laughed. "Don't treat him like glass, either. It frustrates him."
"Why's he so important?" demanded Jack, narrowing his eyes. "Why is a total stranger living in your house? It's not like you, Kalin."
Kalin sighed. "He's a good kid, ya know? And he's only 16, which makes you two years older than him. How could I leave a kid like that alone in a hellhole like he was living in?"
Crow nodded. "I see what ya mean, but why here? You coulda left him with Martha. He'd have more people around to take care of him."
Kalin shifted uneasily. "Honestly? I really thought he'd fit in well with the guys. I guess you probably can't see it yet, but I was thinking he could stick around."
"Can he duel?" challenged Jack.
Kalin smirked. "Of course he can duel; that's how I found him. He's amazing. If he dueled me, I'm not sure who would win. His deck is seriously hardcore."
Both visitors stilled for a moment.
Crow whistled. "That's a pretty big claim, man. Ya seen 'im duel before?"
"Yup." Kalin popped the 'p' with an incredibly smug look on his face.
Crow paused, brow wrinkling in confusion. "Wait, if he's blind how does he duel?"
"He started with a friend reading off the cards to him and built a gadget that scans the cards and plays back their names, points, and abilities to him through an earpiece. It's installed in his duel disc."
Jack blinked. "A gadget, you say?"
Kalin, knowing where he was going, answered immediately. "He's a good mechanic too, and sometimes he talks like Bruno."
Jack and Crow both stared at him in shock.
Crow recovered first. "It takes all kinds…" he finally managed.
"Can he help with our runners?" Jack demanded.
"Yeah, he's already worked on mine. He cut down the cool time for the boosters by half. He'd probably be able to do even better if he worked with Bruno. He can't use any visual schematics or design programs, but he can build a wicked engine from scratch in just a couple of hours," he added.
"Pretty impressive," agreed Crow. "I say he stays."
"I'll tolerate him."
"Guess it's settled then."