A/N: Hello all, this is the very first fem Jaune x Sisters story on the site. This sinful filth will be the first in a new wave of yuris to come out, so have fun reading!

Their Sin

Summary: They couldn't help it. They were attracted to her, in the most sinful of ways, and Joan wasn't sure how exactly to handle their sin. "Wait, ALL of you love me?"

*Chapter 1*

The Arc family in Nibelheim was one that was quite strange. Juniper and Alexander Arc were parents to eight children, all of them daughters.

Janette was the oldest daughter, and a full-time huntress. Her light hair was dyed with blue streaks, and unlike the rest of her family, she had a love for explosives, whether it was blowing a bolt with only a whisper of a sound or rigging a dozen barrels of gasoline to create a firestorm from hell. Ironically, her temper was nonexistent; she kept a cool and calm head at all times, the twenty-five year old often being the lone voice of reason during family disputes.

Jenna and Jade were the first set of twins. Jade had long spiky tresses, and Jenna's hair was long and flowing. The two were graduates of Beacon Academy as well, and earning a reputation for their swordsmanship. Jade was brash and aggressive, relying on her sword's sheer weight and size, whereas Jenna's long odachi was razor sharp and perfect for her quicker, more composed style. The two celebrated their twenty-third birthday over a week ago, and yet to their parents' annoyance, had yet to outgrow their childhood mischievousness.

Jane was the third oldest at twenty one, and considered the taskmaster of the family. Unlike the rest of her family, she had chosen to not be a huntress and instead focused on being a blacksmith. It was her who made both Jenna and Jade's weapons, making them perfect for killing Grimm. Her hair was always found in a long, elegant braid that fell all the way down to her backside.

Julia and Jan were the second pair of twins at twenty years old. Jan had a love for beating the living hell out of Grimm with her twin maces and letting out loud victory yells, and Julia was very, very quiet. She only spoke when necessary, and sometimes not even then. Quite a few spread rumors about the black sheep of the Arc family secretly being into the forbidden art of necromancy, but no one dared to say it to her face in fear of her twin and the youngest sister of the family. Julia would often blush every time someone teased about her having a crush on her little sister, and wouldn't say anything.

Jeanne was the second youngest, at nineteen. The self-proclaimed 'slayer of one thousand Grimm' loved to boast about her prowess in battle to no one in particular, and was fiercely protective of her little sister, getting into quite a many fights with boys who couldn't take no for an answer. Those who dared to hurt her in any way were sure to feel the wrath of Jeanne's claymore.

And finally, there was Joan. The 'baby' of the family, at seventeen years old, there were many adjectives one could use to describe her. Lovable, adorable, and a bit of a ditz to name a few. She was practically the spitting image of her mother, with the same blonde hair and even the same sort of fighting style. She was a sweetheart, unless someone messed with one of her big sisters. She flung herself headfirst at a boy who tried to grope Jane, pounding him with her shield until she had to be dragged off of him. Joan wasn't the best fighter, and ended up on her ass more than anyone during family sparring practice.

And by Oum, if she had to hear the words, "Joan, are you okay?" one more time, she'd start believing they cared about her more than in a sisterly way. If only she knew that it was true.

Jenna sighed as she walked into Jeanne's room. "What is it now? I swear, if it's another 'I think I like this guy', I'm really going to smack you."

Jeanne squirmed, her face crimson, and the older Arc sister rolled her eyes. "I'm right, aren't I? Sis, you can't—"

"It's not a boy," Jeanne interrupted. She shuffled her feet, and the typically boastful girl was unusually quiet.

"Oh, so you're batting for the home team?" Jenna's annoyed expression was replaced by one of endless teasing, and she smirked. "Oh, now this truly is scandalous behavior. I never expected this from you. So, who is it?"

Jeanne shook her head violently, drawing her knees up to her chest and rocking back and forth. "I can't tell you…you wouldn't understand."

"Fine. I'll guess." Jenna folded her arms. "Is it someone we know?" 'No fucking way. I thought I was the only one who was out of the closet and proud of it.'

A nod answered her. "Very well. We see her every day."

"Okay." Jenna pursed her lips, thinking. 'So, someone we know, and we see her every day? But the only one I can think of is…'

She stopped, her jaw falling to the ground. "No way…you're kidding me, right? You have a crush on her?"

Jeanne looked away guiltily. "I told you that you wouldn't understand…"

"Understand what, that you have a crush on your little sister?" Jenna sighed and took a seat next to her, rubbing her back. "I'm not sure if you've noticed, but you're not the only damn one who does. Janette and I have been talking about it the past week or so. I'd be very surprised if Jade doesn't. Jane either doesn't or is hiding it well, and I know for a fact Julia and Jan do. Come on, haven't you seen how they act around Joan?"

"I thought they were only doing it for a bet or something," Jeanne mumbled.

"You are unbelievable, little sis." Jenna gave her a pat on the back, giving her a sympathetic smile. "One word of advice, as we're finding out the very hard way."

"What?" Jeanne sighed.

"Make sure you're obvious about it to Joan. She's an idiot about this kind of stuff," she replied, walking out to give her sister some alone time.

Jenna honestly wished she was kidding about it, too. As much as she and the rest of her sisters loved Joan, the youngest member of the Arc family was probably the most clueless when it came to taking hints.

Janette even tried to get Joan for herself after sparring practice, saying she could 'show her a few moves'. And true to form, Joan didn't get the not-so-subtle innuendo and said that she couldn't dance.

Jade and Jenna howled with merciless laughter at Janette's loud groan of frustration after witnessing that one.

In a way, Jenna was glad that Janette didn't get Joan first, even if the rivalry was friendly. It was a competition between them, after all.

And the prize was Joan.

It was strangely arousing to her. The idea of performing lewd acts on her own sister was as exciting as it was forbidden. It was such a sinful act, and yet it was one she'd enjoy tremendously.

Jenna walked into her and Jade's room, and she found her twin waiting on her bed. Jade gave her an exasperated look, peeking up from her dirty magazine carefully disguised as a weapons catalogue. "You are un-fucking-believable, you know that?"

"What do you mean by that?" Jenna grinned, amused at her twin's reaction. "I didn't do anything but offer good sisterly advice."

"Uh huh, sure." Jade rolled her eyes, voice dripping with sarcasm. "I'll believe that when pigs grow wings. I thought it was supposed to be your and Janette's sin, not hers. I refuse to believe you want more competition for Joan."

"Are you accusing me of secretly trying to start an incest harem so Janette can't have sweet little Joan all to herself?" Jenna's smirk grew. "I'm almost offended, sis."

"Keyword: almost." Jade grabbed a pillow and threw it at her. "Pain in the ass."

Jenna batted it away with a lazy flick of her wrist, grinning mischievously. "I don't see why you continue to deny you have a crush on Joan. It would be so much easier to admit that you do rather than hold in all this denial. You'll only hurt yourself in the long run." 'It's so much fun to tease her. Sorry Jade, but you're too much fun for me to resist teasing.'

Jade's face lit up, and she started to stutter a bit. "I-I don't!"

'Gotcha.' Jenna strutted over to her, poking her in the chest playfully. "The way you blush says otherwise, dear sister~."

"Oh shut the hell up," Jade grumbled, throwing another pillow. This time, it met its mark and hit Jenna in the face.

Jenna recovered, chuckling menacingly. "Oh no, now you've awakened the one winged angel of tickle torture." She pounced like a tiger, pinning her twin down and ruthlessly tickling her sides.

"W-would you stop calling yourself that!?" Jade gasped out, giggling like a madman as her sister tickled her. "S-stop it! I give up!"

"Do you really? I don't believe you." Jenna's hand crept down to her legs, pinching them a little.

"Eep!" Jade squirmed, trying to get away from her. "C-come on! I give up!"

"Good." Jenna let her sister go, and Jade sat up, clutching her sides and giving her a dirty look.

"Never…do…that…again…" she wheezed.

"Come here, you." Jenna smirked and pulled her in for a tight hug, giving her butt a gentle pinch. "The sooner you tell Joan, the better."

"You really think she'll just take it no problem?" Jade sighed, not even bothering to retaliate for the butt pinch.

Jenna smirked and patted her shoulder. "Puh-lease. Once that ditz realizes it, undoubtedly because of me, you, or Jeanne, we'll be gravy."

"I knew it." Jade rolled her eyes and gave her an exasperated look. "This is part of some grand scheme of yours to make sure that Janette doesn't get her to herself, isn't it?"

"I plead the Fifth."

"Pain in the ass…"

Jenna rubbed her hands gleefully, stealing a look at the clock on their bedside table. The bright red letters shone 3:30 pm, and she winked. "So, dear sister, what do you plan on doing while we wait for Mom to get back from her shopping trip with Joan? If you need help, I'll be glad to lend a hand to a sister in need~."

CRASH!

"Jade, put your Buster Sword down. I can't fuck Joan if the house is in shambles."

Joan struggled up the steps, carrying five bags worth of clothes that her mom insisted on buying. "Oh come on!" 'Why does she need this many clothes? She won't even wear half of them!'

She let out a sigh, trudging into the house. "Hey, we're back."

Immediately after she spoke, she was instantly swarmed by her older sisters. "Waah! Hey!"

"Joan!"

"We missed you~."

"Welcome back!"

"Sorry you had to endure her torture! I'll go next time!"

Joan struggled through the blonde maze of bodies, blushing as they fawned over her. "Guys, I'm okay. Really. It wasn't that bad."

Ever since she turned fifteen and had her aura unlocked, she didn't understand why her sisters acted like this around her. They constantly fussed over and were extremely protective and clingy. Almost…too clingy for it to be purely overprotective sisterly acts. 'What if…they're trying to say they like me?'

'Nah, that wouldn't happen.' Joan dismissed that idea quicker than it had formed in her head. There's no way her sisters would do that. She knew that incest was a thing from some of the naughty books she read in secret, but she didn't believe for a second that her own sisters would feel that way towards her. She'd know.

Right?

"Hey, let her breathe, will you?" Jenna's voice spoke louder than the rest. "Joan, something came in the mail for you. It's waiting for you on your bed. Don't worry about this; me and Jade will take care of it."

"Thanks, Jenna." Joan gave her a relieved smile. She could always count of Jenna to be reasonable whenever Janette wasn't around. "You're a lifesaver."

"Anytime, kiddo." Jenna winked.

Joan managed to free herself from her sisters' evil clutches and ran up the stairs to her room, curious as to what could have come in. 'That's a little weird. I don't remember ordering anything, and it isn't my birthday.'

She headed inside, and like Jenna said there was a small package waiting for her on her bed, wrapped with a light-ish red bow on it.

The blonde unwrapped it and saw that it was a notebook, with 'For Joan' written on it. "Huh. I wonder what this is about."

She opened to a random page and started to read.

Joan looked up at the girl whose thighs she was between, planting gentle kisses on them. "Feel good?"

The girl nodded weakly, moaning as Joan's tongue gently circled around her wet sex. "J-joan~!" The two had been at it for hours now, and both of their desires burned as bright as ever.

Joan's tongue licked eagerly, tasting more of her, and she gave her sensitive clit a loving kiss. "You're so beautiful. I love you."

Her tongue slipped inside her, and the girl screamed out as she orgasmed violently. Her nectar gushed out, and her creamy thighs kept Joan's head in place. "Joan~! Kyaa!"

She shook, and she pulled Joan on top of her for a sweet, loving kiss. "Oh Oum, I love you so much."

Joan's face was redder than a tomato, and she dropped it in shock of what she just read. "D-did I just read a book of me having sex with someone!?" 'Who the hell wrote this!?'

She picked it up, and read the last line on the page.

Joan kissed back, entwining her hand with hers. "I love you too, sis."

"WHAT!?" Joan shrieked in shock. "I-I just read an incest smut of myself! Jenna! You better explain yourself!"

She stalked out, ready to give her mischievous older sister a serious tongue-lashing. When she got to Jenna and Jade's room, she was in for one hell of a shock.

Jenna was on her bed wearing a pair of lacy silver panties, and a hungry smirk was on her face. Joan froze in shock, and Jenna stalked over to her like a tiger. "What's the matter, sis? Cat got your tongue~?"

"I…I…" Joan backed up until she hit the wall, and Jenna sexily strutted towards her, cupping her chin and dragging a finger down her chest.

"Oh, Joan…" she sighed. "You have no idea how painful it's been, hiding this shameful secret from you."

"S-sis…"

"Shush. No words…" Jenna placed a finger on her lips to silence her before tilting her chin up. "By the gods, you are absolutely irresistible…"

"You mean you've felt like this the whole time?" Joan whispered. "Why didn't you tell me?"

Jenna rolled her eyes. "You are a complete dunce, Joan. Our hints haven't exactly been subtle."

"Our?"

"Janette and me."

Joan looked down at the floor in shame, her face crimson. She felt bad for not recognizing the problem sooner. "All this time…and I didn't notice. I'm sorry, sis."

"You can make it up to me this way." Jenna placed her lips on hers.

Joan let out a muffled squeak of shock, trying hard to comprehend that her own sister was kissing her.

And she liked it.

Jenna pulled away, giving her a lazy grin. "It felt good to get that out, Joan." She let Joan go, and she winked at her. "Don't go too far now~. We're not finished~."

She walked towards the bathroom, presumably to take a shower, and Joan slumped down to the ground, touching her lips. "W-why?"

"Why do I like this?"

She didn't understand why, but she knew one thing.

This was their sin.

A/N: And that's it for the first one. This fic won't be too long (seven-eight chapters), and will be updated fairly regularly. So, I hope you enjoy the future chapters of this sinful fic!

Discord: DPL #5371