Chapter 1

It was shaping up to be a nice afternoon. I'd spent the morning finishing up my summer homework, so the rest of the day was dedicated towards relaxing and doing nothing important. I'd even finally managed to get that one drop that was being a total pain earlier, too. Argo was gonna be totally furious when he found out I got it first, without his help.

Yep, this was a nice day, and nothing was going to disturb my nap on the couch until dinner was -

A heavy weight decided to land square on my center. "Oof," I grunted, the wind rushing out of me, and cracked an eye open to glare at my sister as she mounted me.

"~Big Bro~! It's time to get up!"

"Yuuki," I grumbled. "What are you... No. Aiko, what is Yuuki doing?" I asked, tilting my head until I was looking at her upside-down.

Aiko looked up from the manga she was reading on her tablet and glanced our way. "I think it's the 'mounted wakeup call'," she said before shrugging and going back to her reading.

"I wasn't even asleep," I pointed out in a deadpan. "And it's after five in the afternoon."

"Should you be telling me that?" The elder twin lifted one leg from the armrest of the chair and lifted it up to drape over the backrest, her head getting closer to the other armrest.

"She never listens to me," I pointed out.

"I'm right here," Yuuki complained, rocking back and forth in what I assumed was annoyance. The problem was, the end result was that anyone looking in from the outside saw something definitely improper.

"Yuuki!" I squawked, squirming until I managed to get out from under her, somehow ending up on the floor without knocking Yuuki off of the couch.

She pouted. "What is it now?"

"You shouldn't do that," I said.

Her Pout - and on her face, it definitely deserved the capital letter - intensified. "Why not?"

"Because it's really something siblings shouldn't be doing together," Aiko said when I struggled for words. "It's usually more of a lovers' thing." She had wriggled around so that she was lying stomach down, halfway over the armrest with her legs swinging freely in the air.

"Oh, then it's fine," Yuuki said, then glared at me. As close as she could get to a glare, anyway, since on her face it looked like an angry puppy. "Since he already said we weren't his real sisters."

I winced. "I didn't -"

"Yes you did." I looked up from where I'd ended up, against the arm of Aiko's couch, at Sugu, who was leaning over Yuuki's couch and glaring at me twice as hard as her younger sister.

"- mean it like that," I finished.

"Well, it doesn't matter," Yuuki said. "'Cause if we aren't real siblings, then I can marry you!" she added brightly.

My answer probably couldn't be classified as a word. My next plea, on the other hand... "Aiko, please..."

She just looked down at me, raising a delicate eyebrow.

If there was anyone that could get Yuuki to restrain herself, it was her twin sister. "Please?" I asked.

She smiled, and I felt a rush of relief. "Nope." And then I felt like crying. "You brought this on yourself, ~Big Bro~," she said, singing her voice with the exact same tone Yuuki used before, and I felt a shiver run down my spine.

"Oh, that's right," Sugu said conversationally, and I looked at her in hope of a reprieve. "Well, Kazuto, you could always fulfil your childhood promise and marry me. We're only cousins, after all," she smiled sweetly.

"I don't remember ever making a promise like that," I said flatly, catching a glimpse of my mom standing behind Sugu.

She smiled, as if enjoying a private joke, and then said, "While I'm definitely a fan of good relations, no matter what kind of relations they are, how about you give Kazuto some space before he overdoses on estrogen." I'm saved! Thanks, Mom. "And dinner's ready."

A smirking Sugu and Aiko followed me to the dinner table, with a laughing Yuuki joining us not much later. "Like I was saying, I didn't mean it that way," I explained while I snagged my food. "I was surprised, because, well... I'd never thought you couldn't be... I never imagined you as anything other than my sisters."

"I imagined Bro as my lover a couple times," Yuuki said cheerfully, and a piece of fish went down the wrong pipe as her words registered.

I coughed a few times, then called her out on it. "Yuuki! That's -"

Or tried, anyway. "-Completely alright, since we're not related," Aiko said with a shrug, studiously not looking my way.

"Don't tell me..." I stared at her.

"Okay, I won't," she said with another nonchalant shrug - that was completely ruined by the wide, Cheshire Cat-like smile on her face.

I looked at Sugu.

She looked away, blushing fiercely.

I let out a sigh, trying to ignore how hot my own ears felt. Sisters.

Maybe if I just ignore everything and pretend our family's something approaching normal...

I was just about ready to close myself in my room for my nightly gaming time with Argo when someone rapped lightly on my door. "It's open, Aiko," I said, knowing she was the only one who would knock like that. Sugu hit a lot heavier thanks to her muscles from kendo, and Yuuki didn't even bother knocking before bursting into my room and throwing herself on my bed. "What's up?"

"Just saying hi," my sister said, sitting on my bed and swinging her legs idly. A quick glance told me she'd just gotten out of the bath, since her long hair was still damp. "You know Yuu and I don't hold a grudge about what you said, right?"

"I figured. I still shouldn't have said it, though."

She smiled. "That's good, I was worried you might think we were mad at you," she said, before rising from my bed and padding over to me. "All of us do love you, Kazuto. The other two just have strange ways of showing it."

"And you don't?" I asked her. "If anything, you're worse than they are." Aiko never started anything, but she was always ready to make any situation worse than it already was.

"Oh, don't say that." She wrapped her arms around my neck and leaned in close. "You'll hurt my feelings."

She was close enough that I could feel her breath on my cheek, and I could smell the flowery scent of her shampoo, and feel her hair tickling the back of my neck, and - "Out," I said abruptly. "You're just messing with me."

Aiko giggled, before giving me a swift peck on the cheek. "Have fun with your games, Kazuto."

"Sisters," I complained to Argo later that evening, while we were busy raiding a boss. "One would be bad enough, why do I have to be saddled with three? And they just won't leave me alone."

"Why're ya sayin' that?" he replied.

I rolled my eyes, even if we were voice chat only and he couldn't see. "Every day, it's something different. I mean, yesterday Yuuki decided that my spot on the couch was more comfortable than where she was sitting, so instead of just asking me to move she made herself at home on my lap. And then the day before that, I swear Sugu was just waiting for me to walk by so she could exit the bathroom in her towel."

"Pfft," Argo snorted before his voice suddenly cut out. I glared at his character. I bet he was laughing and muted his mic so I wouldn't hear.

"I know you have a sister," I said to Argo a few seconds later. There was this one time we did a video call, and Argo had his sister talk to me instead. She was cute, with a mischievous smile, and I didn't really bother calling Argo on the swap. It was definitely something he'd do just to laugh at my reaction. "Does she do stuff like that? Also, boss gonna spam fire breath, buff us."

"I know," he replied, and his character started casting buffs on everyone in the party. "Eh, m' sis does some 'f the stuff yer talkin' 'bout. Not 'xactly like yer describin', less like she's tryin' ta seduce me an' more like she jus' doesn't care I'm aroun'."

I shrugged. "I guess."

"Should be done with the breaths in five, so get ready for DPS," Argo told me. "An' sounds ta me like yer sisters 're tryin' ta get ya to see 'em as women."

I blanked for a second as I processed that and almost missed my chance to start hitting the boss. "Don't say things like that, they're my sisters." I said.

"'Course they are," Argo drawled, and I grumbled under my breath. "Didn' ya tell me they were 'dopted or somethin'?"

"You're no help at all, Argo."

Later, after we beat the boss and dissolved the pickup party, I leaned back in my chair. "You said you got into the SAO beta, right?"

"Yeah, jus' like you," Argo replied. "Gonna be wild, yeah?"

I grinned. "Can't wait."

"Ya gonna be cool wi'out yer sisters? I mean, yer always talkin' 'bout how ya spend a lotta time with 'em, righ'?"

I shook my head. "Yeah, I'll be fine. The twins said they're gonna be getting a part-time job, and my other sister said she's gonna be busy too." Not sure why Yuuki and Aiko want a part-time job suddenly, but Sugu had another kendo tourney during the month of the SAO beta.

Argo snickered. "Well, I'll see ya in th' beta, 'kay? Later, Kirito."

"Later, Argo."

"Hello, Kazuto," the woman said with a smile. "My name is Midori Kirigaya."

"...Hello?"

"I'm your aunt."

I inhaled sharply. My parents had... "Oh. Are you here to adopt me, then?"

She smiled. "You're quick, just like your parents told me. Yes, I'm here to -"

"Nooo!" a young girl's voice wailed. "You can't take Big Bro away from us!"

I was tackled by a long-haired missile and knocked over, falling on my butt. "Ow... Yuuki," I complained. "That hurts."

"And who are you?" Midori asked, looking a little confused.

"I'm, uh..." Yuuki trailed off and tightened her hug around my waist."

"My name is Aiko," the elder twin said politely from where she was standing at the doorway. "That's my sister, Yuuki."

Midori looked at the two of them, then looked at me. "Sorry, girls, can I speak with Kazuto alone?"

Yuuki looked up at me, and I patted her head. "It's okay," I told her.

"Promise you're not gonna leave us?"

"Promise."

In an instant her smile was back. "Okay! Let's go, Sis!" She let go of my waist and hurried over to where Aiko was waiting before the two of them ran out of the room, Aiko leading like she usually did.

"They seem to care a great deal about you," Midori said once she'd closed the door again.

I scratched my cheek. "They... lost their mom and dad too."

She sighed. "Oh... Well, I guess that changes things..."

"You're not... going to..." I sniffled. I wasn't going to cry. I wasn't...

"What? Oh, no no no, I'm still going to adopt you," she said hurriedly. "I just have to look into the paperwork for adopting three children instead of just one."

"-zuto. Kazuto, wake up, it's morning."

I groaned and opened my eyes. "G'way, Sugu," I groaned. "'m sleeping."

My sister huffed. "If you don't get up, I'm letting Yuuki do the wake-up calls from now on."

I sighed. She was playing dirty and we both knew it. She made that threat every morning, but she still hadn't followed through with it. "Fine, fine, I'm getting up." I sat up, realizing after a second that I had a small problem. "Um, Sugu?" I asked her, and her eyes snapped away from my shirtless body. "Can you, y'know... go out, so I can get dressed?"

"Uh, yeah," she said. "Just don't go back to sleep or it's Yuuki coming in next."

"I'm already up," I protested.

After I got dressed, I opened my door and headed downstairs, still yawning. "Morning," I said as I sat down in my usual chair with a thump.

"Good morning, Kazuto," Aiko said lightly from her chair, where she was reading her tablet.

I took one look at her and felt my face burst into flame. "Aiko," I choked, "what are you wearing?"

"Hm?" she asked, glancing up at me and then down at the silky clothes that were way too tight on her. "Oh, these are my new pajamas. Do you like them?" she asked, leaning forward.

I definitely reacted to that, and was glad that I was sitting down. Like Sugu and her twin, Aiko was an early bloomer.

"Morning," Yuuki called out, getting both of our attention.

And of course, she was wearing her new pajamas, too. When did they even buy those?!

"Oh, did you tell him yet?"

"Nn-nn," Aiko shook her head. "I was waiting."

"Tell me what?" I asked.

"Not yet, not yet!" Yuuki said hurriedly. "We have to wait for Sugu!" And Sugu was involved in whatever this was? Did I want to know? It might be more of them making fun of me for what I said a few years back.

Shrugging, since I'd tried getting Yuuki to tell me her secrets before and I never succeeded, I got busy with eating my breakfast. I needed to eat a big breakfast and lunch, since today was the launch date for SAO. I couldn't wait until the servers went live.

Throughout all of breakfast, my sisters were all but vibrating in their seats. Whatever this secret was, it was definitely important. "Alright," I sighed, setting aside my breakfast dishes once I'd picked them clean. "So what are you three hiding?"

"Eheheh," Yuuki laughed. "Ready? Three, two, one!"

Simultaneously, all three of them pulled their surprise out from behind their backs and showed it to me.

I stared in shock at three identical copies of Sword Art Online.

"What?" I asked them. "How?"

Sugu grinned at me. "Well, we knew how excited you were about the game," she said, "and we wanted to have some fun, too! So since everyone else is going to be new to the game, this was the best time to have you teach us how to play."

"Yup!" Yuuki cheered, throwing up a V for Victory sign as she beamed at me. "Me and Aiko worked all August to be able to buy our copies. Sugu asked Mom for the prize money from her kendo tournament."

I sighed and folded my arms, looking at the three smiling girls in front of me. "And you're not going to let me say no, are you?" I sighed. When they all shook their heads, I sighed again. "Alright, alright, fine. We can play together. Just, go get your NerveGear calibration done first thing, and then we can figure out how this is going to work."

"I'm sleeping with Big Bro first!" Yuuki cheered.

I choked on the air, coughing to clear my throat. "What?" I rasped. "Yuuki, what-"

"Huh?" she asked, looking at me in confusion. "When we use the NerveGears, it's like sleeping, right? So I want to sleep on your bed next to you, Big Bro! I called it first!" Off to the side, Aiko looked away and muttered something, while Sugu frowned.

"O-oh..."

"Did you think I meant something different?" Yuuki asked me curiously.

"Not at all," I said flatly. She just giggled. After what she said during dinner yesterday, was it a surprise I jumped to a conclusion? Especially with the misleading way she said that.

The rest of the morning, I spent on my computer, watching a live stream on the sale of SAO. It was insane how long some people had to stand in line, and I wondered how long my sisters had waited to buy their copies.

When there was only ten minutes before the launch of the servers, I went out of my room and knocked on the door to Aiko and Yuuki's room. "Hey, you two," I said when Aiko opened the door. "Just wanted to let you know, when you log in you'll be in a large plaza. There's a fountain in front of you, so either find or wait for me there."

Aiko nodded, while Yuuki was busy grabbing all of the equipment for her NerveGear and holding it in her arms. As soon as I stepped to the side, the younger twin ran over to my room and headed inside. Right, yeah, I forgot about that. Somehow.

After giving Sugu the same heads up I gave the twins, I returned to my room to find Yuuki already curled up on my bed, waiting patiently for me. "C'mon, Big Bro, hurry up," she said, patting the bed. "It's almost one!"

"I'm coming, I'm coming," I said, already regretting not putting my foot down and insisting she Dive with Aiko. At least Aiko could get her twin to focus.

I got the NerveGear hooked up and snug on my head before I laid down. Yuuki, of course, immediately grabbed on to my arm and pressed it close to her chest, cuddling close to me. I blushed as I felt my arm trapped between two soft pillows, but it wasn't like I could say anything. "Ready?" I asked her.

"Yeah!"

"Link start!" we chorused.

My account data was still present, carrying over from the beta, so I didn't have to set up a new account. Instead, I was able to keep my beta avatar, saving me some time.

When my vision cleared, I looked around. Everything I could see was exactly how I left it, from the blue sky to the cobblestone under my boots. "Hello world," I said, grinning. "I'm back."

Like I'd expected, I was the only one of us actually finished, so I decided to take a break and wait, looking at all the new players to see if I could figure out which ones were my sisters.

All in all, it was surprisingly easy. Yuuki was the easiest one to pick out, since her appearance was virtually unchanged outside of her hairstyle and eye color. I almost missed her, since I was looking for her short black hair instead of the long flowing purple hair she was sporting, but the bright red headband she always wore to keep her bangs out of her eyes gave her away.

From there, it was easy to pick out Aiko; she had to be the one that was somehow keeping Yuuki relatively focused instead of bouncing off every wall in sight. Her appearance wasn't all that different from real life, either, just subtly different here and there. I guess the twins were satisfied with how they looked, unlike me.

I looked at the players talking to the twins. If they were Aiko and Yuuki, then that would mean that Sugu was...

I couldn't help staring. I mean, Sugu's avatar was blonde, with her long hair pulled back into a ponytail. But that wasn't the, uh, most striking change.

I will not think about my cousin's breasts, I will not think about my cous-SISTER's breasts, I will not think about my sister's breasts...

My sisters talked to themselves for a few seconds before turning and heading toward the fountain, like I'd told them. I rose up from my seat and waved to catch their attention, and instantly Yuuki started running towards me. "Big Bro?" she asked, looking me over.

"It's me, Yuuki," I said. "Everything go okay?"

"Yep!" she said, beaming at me as Aiko and Sugu joined us. "What do you think of the avatars, Big Bro? Do we look cute or what?"

"Very cute," I agreed, patting her on the head. Yuuki giggled. "So, first things first, I'm going to send you all a party invite. When you see a panel pop up in front of you, hit Accept."

After I invited them all to a party and had everyone add each other to our Friends List, I glanced at the avatar names they'd chosen for themselves. Leafa was Sugu, Ran was Aiko, and... "Yuuki," I told her, "you're not supposed to use your real name for the name of your avatar."

"Tehehe," she laughed, bonking her head and sticking out her tongue. "My bad."

"Well, not like we can change it now," I sighed. "So, now that everything's set, we should head out to - Leafa? Is something wrong?"

She was staring at me intently, and I shifted under her scrutiny. "I don't like it," she said finally. "I like your normal face more, Kazuto."

"What's wrong with my avatar?" I protested, pride stung. I liked how I looked in SAO.

"It's not what we fantasize about at night," Ran said casually. I blushed, regretting that I'd asked. A quick glance showed me that Leafa was blushing too, though Yuuki was as casually cheerful as ever. "So, Kirito, where are we going? You were saying something before you got distracted?"

On one hand, I appreciate that she was getting down to business, but on the other hand could she do that so without the knowing, cat-like smug smile?

"Y-yeah," I said, coughing. "Like I was saying, now that we're all together let's head out to the fields, and I'll teach you how to fight."

"Okay~," my sisters chorused.

I felt... strange. Like I wasn't processing what I was hearing right.

...cannot log yourselves out of SAO, and no one from the outside will be able to shut down or remove the NerveGear from your head.

"Kazuto, I'm scared," Leafa said, pressing close to me. I wrapped an arm around her automatically, just like I did when she snuck into my bed during a thunderstorm.

On my other side, I felt two more warm bodies and shifted so that Ran and Yuuki could cuddle closer to me. I was their big brother, I was supposed to keep them safe. But this was my fault. I'd dragged them into this.

...no longer any way to revive someone within the game. If your HP drops to zero, your avatar...

If it were just me, I wouldn't... I wouldn't be so worried. I knew what I could do, and if I played my cards right I could make it to Horunka by tonight, grab the Anneal Blade and some quick levels. I didn't have anything to fear, at least until my beta knowledge ran out.

But it wasn't just me. My sisters were here too. Yuuki, Aiko, Sugu... They were in danger.

I couldn't just run off. I had to protect them.

...the end of the tutorial and the official launch of Sword Art Online. Players, I wish you the best of luck.

It still felt like a dream had suddenly turned into a nightmare, but I couldn't hesitate. "Let's go," I said, tugging at my sisters. They followed me, even Yuuki being unusually quiet. It might have been a combination of Kayaba's announcement, or how we'd been returned to our real-life appearances, but seeing my normally energetic sisters like this made something twist in my stomach. They were supposed to be happy.

Once we'd slipped out of the crowd of screaming and panicking players and made our way into one of the alleys, I stopped and turned to face my sisters. "Okay," I said. "The way I see it, there's a few different options, but the safest thing to do is for you three to find an inn nearby and rent rooms. The starting amount of Col won't last long, but I'll send more, I promise."

Yeah. The best thing to do was to make sure they were safe. If I was by myself, I could fight without worrying that they'd -

"No!"

I stared in shock. "Yuuki, you have to -"

"I said no," she repeated, frowning at me. "You can't just leave us alone. You promised, remember?"

I sighed. "Ran..." If her twin asked her, Yuuki would go along with the plan. "Please, you have to -"

"Nope," Ran said, folding her arms. "We won't let you just abandon us and put yourself in danger."

"Yeah!" Leafa added. "I'm not going to let the person I love do everything," she said. "You taught us how to fight, so we want to fight with you."

I studied all of them, watching me with fire in their eyes, and then sighed. I'd never been able to say no to them, especially when they really, really wanted something. "Okay," I said finally and against my better judgment. "But that means we have to work extra hard to stay safe."

My sisters smiled. "Hooray!" Yuuki cheered. "Wait... Darn, this means we don't get to use Plan B!"

"...Plan B?" my mouth asked before my brain could stop it.

"Oh, that one's a lot of fun," Yuuki said cheerfully. "We'd just take turns kissing you until you agreed. Whoever gets you to agree gets to be your lover first!"

"...That's..."

"Still completely acceptable," Ran said, giving me a wide Cheshire-like grin.

At least Leafa wouldn't look at me, even if her luminescent blush and dreamy smile gave away exactly how she felt about Plan B.

I wish they would at least try to hide it...

So hey check out this stupid thing that I'm doing

This story originated from a plot idea I found while reading a forum thread on SAO ideas, and I found a snippet where Yuuki and Ran were also Kazuto's siblings, and then the idea just wouldn't leave me alone so I'm writing it for shits and giggles and also because I want to write things other than Nightblade from time to time.

The first scene is mostly the other person's original snippet, so credit to that guy/girl, though I shifted it around a little for shenanigan reasons. Everything else is pure Knight, don't worry (that's why its terrible i know right)

Two main points of AU divergence: one, Yuuki and Aiko's mom died, so they never got the blood transfusion so they never got HIV because these two are precious babies and nothing bad should ever happen to them. And two, Kazuto's adoption took an extra year or two to go through, so he's old enough that he knows that Midori is his aunt and not his mom. (also Argo is still Argo, Kazuto's just a dumb idiot when it comes to girls (Argo's sister mentioned is her older sister))

Story stuff:

1) Point of view is consistently first person. Probably going to stay in Kazuto's head. It'll lose out on some shenanigans later, but meh, I like it in here, it's comfy.

2) This story might end up a little… explicit? Given the subject matter, that shouldn't be a surprise. Anything physical will happen off-screen, since underage kids and all that, but the first chapter should be a good indicator of about where this story will be heading. Probably the most explicit thing I'll be discussing is nudity, and even then it'll be like 'Yeah their clothes are gone MOVING ON.'

3) In this case, incest equals win-cest. Happy days!

4) The main focus won't be on fighting, but on the shenanigans Kazuto's sisters will get into while trying to get into his pants. Slow burn on romance, mainly because Kazuto's a shy boy.

5) Update schedule is 'Whenever the heck I feel like it.'

Right, that should be everything! Enjoy, folks. Kazuto's sister problems have begun~

Also you might have noticed the default story image, it'd be fantastic if some kind soul could whip up a cover for this. (/shameless begging)