They enjoyed a lazy Saturday morning, a surreal domesticity settling over them. Breakfast was a quiet affair, punctuated by stolen bites of toast and shy, fleeting glances.
The tension was still there, a low, electric hum beneath the surface, but it was different now. It was the tension of a live wire, not a tripwire.
They left the house at ten, the bright morning sun feeling both cleansing and exposing.
"So…" Makoto began, a nervous giggle escaping him. "I have no idea where to start. Where are we buying all this stuff?"
Yuna stomped ahead, her twin-tails bouncing with a familiar, bratty energy that felt strangely comforting. "Obviously, Akihabara, you idiot."
She shot him a glare over her shoulder, but there was no real heat behind it. "And don't even think about holding my hand in public unless you want me to scream incest predator at the top of my lungs."
She led him down a series of narrow, bustling alleys lined with colorful, overflowing fabric stalls.
Her fingers, surprisingly deft and knowledgeable, trailed over bolts of silk and cotton, her expression one of focused, professional concentration.
"This one," she declared, slapping a roll of sky-blue fabric with a definitive thud. "For Ganyu's main outfit."
Then her smirk turned wicked, a familiar, dangerous glint returning to her eyes. "And this..." she held up a bolt of sheer, shimmering lace, the fabric catching the light like a spider's web "...for the lingerie I'll wear underneath. So when some creep asks for photos at the con…"
She leaned in, her breath a hot, conspiratorial puff against his ear. "…only you will know that your little stepsister is wearing under all that modest cosplay."
She tossed the fabrics at him with a haughty sniff, her authority absolute. "Now pay up, big bro. And don't forget the unicorn pajamas."
Her nose wrinkled in a gesture of mock disgust. "Disgusting." But he saw the way her eyes lingered on a pastel pink set with matching, iridescent horns.
Makoto paid for the mountain of fabric, his wallet weeping silently.
"Well, I didn't know we'd need this much," he sighed, a genuine note of surprise in his voice. He hefted the heavy bags, a strange, domestic satisfaction settling in his chest.
"Do we need to buy props too? I seem to remember I broke your horns last time, haha." He scratched the back of his hair, a nervous, self-deprecating gesture.
Yuna's face turned a shade of nuclear red. She kicked his shin, the blow landing with pinpoint accuracy that made him yelp.
"Shut UP about the horns!" she hisses, glancing around frantically to see if anyone overheard. "And yes, we need new ones because SOME ANIMAL snapped them when he bent me over the..."
She cut herself off with a strangled, frustrated noise, grabbing a pair of sturdy-looking resin horns from a nearby prop shelf.
"These," she muttered, shoving them at him. "Unbreakable. Because apparently, my brother can't control himself when I'm in cosplay."
The cashier, a young woman with a bored expression, coughed loudly. Yuna beamed at her with a terrifying, saccharine sweetness. "It's a sibling bonding project!"
"Phew, props and fabric done, I guess," Makoto sighed, the weight of the bags a pleasant ache in his arms. "Should we go check for lenses and wigs too?"
Yuna's eye twitched. "You're enjoying this way too much," she muttered, but she was already dragging him by the sleeve toward a nearby wig shop, a determined, single-minded focus in her stride. "And don't get any ideas, this is strictly for cosplay purposes."
Inside the shop, a chaotic explosion of color and synthetic hair, she immediately pounced on a long, flowing blue Ganyu wig, holding it up to the light with a critical, appraising eye.
"This one," she declared. Then, with a wicked grin, she grabbed a short, bright cream-color wig: Klee's signature, bobbing style.
"And this. For when you inevitably beg me for the loli package again."
She shoved both wigs at him before marching over to the contact lens display. "Aqua blue for Ganyu," she mused, her finger tracing the display case. Then she held up a pair of vibrant, crimson red ones.
"And these are for…" Her smile turned dangerous, a silent, sinful promise. "…secret private shows."
She dropped them into his basket with a triumphant smirk. "Your wallet is crying, isn't it, big bro?"
Makoto looked at the growing pile of expensive cosplay supplies in his arms, a sense of grim, financial reality setting in. "Well, kind of," he admitted with a shrug and a theatrical, mock sob.
"Now I understand why those pre-made sets are so expensive."
He looked at her, a playful, lewd glint in his eye. "I think I need some… consolation for all this lost money."
He slapped her ass, the sound a sharp, satisfying crack in the quiet shop, then grabbed and squeezed it with a possessive, proprietary gesture.
Yuna yelped, a sound of pure, unadulterated shock, and jumped a foot in the air.
She whirled on him, her eyes blazing with a murderous, incandescent fury. "YOU!!!" She grabbed the nearest wig stand, a styrofoam head adorned with a garish purple bob, and swung it at his head like a medieval club.
The shopkeeper, who had been quietly organizing a shelf of hairspray, gasped in horror.
"Die! Pervert! Degenerate! Incest pig!" Yuna shrieked, chasing him through the narrow aisles, the wig stand a weapon of righteous, sibling fury.
But her face was flushed a deep, furious crimson, and her breath was coming in uneven, ragged gasps, and it wasn't just from the rage. He could see the thrill in her eyes, the dark, exhilarating excitement.
When he finally ducked behind a mannequin dressed in a bizarre, futuristic sailor uniform, she leaned in close, her voice dropping to a venomous, thrilling whisper. "Touch me like that again in public, and I'll make you buy the entire fucking shop."
She skipped away, a triumphant, wicked bounce in her step, and sweetly handed the abused wig stand back to the horrified clerk.
"Just some sibling play-fighting~" she chirped, her voice a mask of pure, innocent delight.
Then, under her breath, a final, damning command to him: "Pay up and let's go. I need to break in these new horns."
Makoto, his heart still hammering from the chase, paid for the wigs and lenses, the clerk pointedly avoiding his gaze.
He caught up to her on the street, a breathless, exhilarated laugh bubbling up in his chest.
"Hmm, that was… kind of hot when you insulted me like that," he chuckled, poking her cheek. "You're a bad stepsister. Maybe you've awakened something you shouldn't have, Yuna."
Yuna's eye twitched violently. "Oh my god," she deadpanned, stomping ahead, the shopping bags swinging wildly at her sides.
"First the incest, and now you're a humiliation kink freak?" She whirled around, jabbing a finger into his chest, her face a mask of theatrical disgust.
"Next, you'll be asking me to step on you while I call you trash."
But her cheeks were still flushed, a betraying tide of pink, and she couldn't quite meet his eyes.
"…Disgusting," she muttered, but there was no real heat behind it. "Just… keep those new and disturbing fantasies in your pants until we get home, you degenerate."
She grabbed his wrist and yanked him toward a nearby café, her grip surprisingly strong. "We're getting boba. And if you even THINK about groping me in public again…"
Her grin was pure, unadulterated evil as she added, her voice a low, thrilling purr.
"Now buy me a strawberry milk tea, you worthless trash."