[Jinko TF, Incest]

Living in a world full of Monster Girl was a difficult task. Especially if you were a girl. That's what Gaoko understood as she did her very best to defend her household, beating back any of the more wild Monster Girls that wanted to try and approach her Brother. Even if all that he did was call her stupid for getting into danger and keep acting so distant, she'd keep doing that kind of reckless thing just to make sure that he ended up staying by her side and not fall prey to the same haze of pleasure that had claimed their parents and transformed her Mom.

But even though she had done a good job so far, even somebody like her could tell that it wouldn't last. If she didn't grow stronger, she'd eventually fall. And to make matters worse, even if she had been able to best the various Monster Girls as they tried to assault their home, they had inflicted more than enough damage to her to the point where she had begun to experience a cycle of heat. Something that she luckily was able to keep under wraps and only deal with whenever her Brother headed into town and allowed her a moment to breathe.

It shouldn't last. She needed to be stronger. Both physically and mentally. She needed to be able to defeat even the greatest Monster Girls in a couple of hits at best, and strong enough mentally to avoid their horny nature rubbing off on her. Just thinking about the Jinko that very nearly bested her, that maternal-looking tiger bitch that tried to take her Brother away from her... Thinking about how her claws had gotten so close to her nethers and teased her...

N-No. Gotta stay focused. Gaoko shook her head as she slowly walked through the streets of the nearby village, wearing a robe that would keep her hidden... W-Well, it would keep the fact that she hadn't worn anything hidden. She had started fighting the Monster Girls in the nude to make sure she didn't ruin any of her current outfits so her and her Brother wouldn't be low on cash, but that had just caused a new need to arise within her.

She just hoped that she could endure that very same need for long enough as she tried to find somebody... Anybody that could help her with her pursuit of pure strength...

Which was when she was rather rudely yanked into an alleyway, causing her fight and flight instincts to rile up as she tried to claw at the one that had grabbed her. Without even realizing it too, glaring straight at them.

"Feisty, but not ferocious enough to touch the merchandise." A brown-haired shady merchant, who wore a robe just as thick as the one in front of her wore, spoke and giggled as she leaned up against one of the walls. "Why the exhibitionist's digs, kitten? You're looking like you're about to break out and ruin somebody's day." To say that she knew exactly what was going on was an understatement. Merchants like her needed to be able to see straight through their marks, otherwise they wouldn't be able to sell squat.

Gaoko blinked before sighing and blushing, pulling down her hood to reveal her beautiful short brown hair that went along well with the brown shade of her eyes. "I... It's not like I want to wear them. I just..." She muttered, leaning up against the other wall as she trembled. Even though she wasn't showing it off, it was like she was naked when that merchant looked at her, which turned her on more than she would like to admit.

"Well, I've got a cure for that if you need it." The merchant said as she tugged down her robe a bit, popping out a nice looking vial full of extremely pink liquid. "Alice Extract, straight from Wonderland. It'll keep your purity while at the same time letting you overcome anything that might ail your mind. Of course, can't guarantee that it'll work forever, but what does in a world like this one, eh?" The merchant snickered, pushing the vial back into her cleavage with a grin on her face. Only to raise an eyebrow. "...You're really far along, eh? A girl like you would've probably slugged me if I offered it any earlier."

"Please." Gaoko trembled, squeezing her robe ever tighter. "I don't care what you give me. Just that you can promise me that it'll make me stronger. I want to protect my Brother. I don't want him to be taken away from me by a Monster Girl. Much less one like you." Despite the fact that she had clearly fallen quite far to the point where a few more pushes was all that she needed to be transformed into a Monster Girl herself, she was still as sharp as ever. That's why she was here in the first place...

The merchant chuckled as she covered her lips, and a pair of tanuki ears popped out of her head. "I admire that devotion, girl." The merchant said, revealed to be a Gyoubu Danuki in the process. "I was just going to sell you something that would instantly transform you and get you out of town so you wouldn't compete with my possible husband, but..." She taunted, before pulling her robe up ever slightly to reveal a pouch latched onto her naked thigh. She opened it and dug into it, before pulling out a very simple looking vial. Not one that was overly long compared to the one that was definitely dangerous, this one was small and barely had a few droplets in it. "This'll do exactly what you want it to. It'll make you even stronger than your common Monster Girl. Stronger than me especially. But in exchange..."

"It has a chance to ruin me." Gaoko said as she plucked the vial from the Danuki, a soft smile on her face. "I'll overpower it. But if I don't, you still need your fair compensation..." She muttered, as she carefully started to lower her robe as if she was offering her body to the merchant as payment...

The Gyoubu Danuki grinned from ear to ear, only to be proverbially suckerpunched as a wad of cash hit her straight in the face, right before she saw any of the goodies. "You absolute tease." The merchant muttered, disappointed as she pulled the wad off her face. Only for her eyes to widen as she realized just how much money she had given her. "Hold on, don't you-"

"I don't. If I have strength, then I can take what I need. Money won't be an issue any longer." Gaoko said with a sly and soft grin. "Thanks. For everything." She said, bowing respectfully before running off, hoping to make it home before the Monster Girls tried anything.

The Gyoubu Danuki just shook her head a bit as she pocketed the money. "Idiot. I'da given it to you for free, in exchange for what that man did." She muttered and sighed. She had once had his eyes on that girl's Father, but not only had she lost to her Mother, both of them were taken away and at that point she couldn't even come close to competing. The least she could do was take care of the man's kids, in her own way, to pay back the debt that she had accrued.

If anything, she hoped that the girl would endure what came next. Because after all the small favors she had pulled, it'd be a shame if a girl like her, with a character that was much stronger than she really believed it to be, would end up falling prey to the strength she wanted to attain...

Ah well. She had more wares to sell. She could always check up on them once night fell...

---

Gaoko took a few steps into the lonesome house that she called home, and judging by the quality of the air, her Brother was still out. If it was more humid, the Monster Girls had been there to steal him. But it was clean and crisp. So they were still on their way, if anything...

Which meant that she didn't have a lot of time. Not only was she currently more turned on than she'd like to be, her cheeks flushed bright red as her nipples poked out against the robe that adorned her body, but she was also still recovering from the last encounter she had. Defeating a Lamia-type girl wasn't easy when all you had were your fists, and it was only thanks to her Brother's timely assistance that she managed to get free... But that squeezing sensation still lingered.

Gaoko pulled out the little vial that the merchant had given her, staring very carefully at it. If she drank it, there was a very strong chance that she'd turn into a Monster Girl if she couldn't hold herself back. But she had to drink it. Otherwise he wouldn't be safe. Otherwise she'd be defeated. And then not only would she be unable to keep him safe, but he'd be abducted and taken as the husband of somebody that he didn't even know.

...She didn't dwell on that last thought for much before she popped open the vial and dunked every little bit of that liquid into her mouth, swallowing it before she realized just how thick it all was. If she had bothered to let it rest on her tongue, it would've probably puffed up and made it impossible for her to swallow.

Once it hit her stomach, Gaoko's eyes widened and she was forced to drop the vial. Because it was like pins upon pins had sunk into her skin and delivered her several doses worth of nothing but pain. It felt awful. It felt like she was about to be torn apart. But she had to endure. Otherwise..!

She grit her teeth, even as the feeling intensified. It wasn't the regular kind of pain that came with fighting against Monster Girls. This was the kind of pain where her body was trying to change. If she didn't resist it, she would end up completely twisting into a wild Monster Girl that would abuse her Brother. And how would she be better than the ones she tried to protect him from if that happened?!

"S-Stay strong, Gaoko..!" Gaoko let out a roar as she tried to keep herself held together, even as fur started to visibly spread across her arms and her legs. Tiger-striped fur that only caused the sensations inside her to spread. They were the needles jamming into her. They were the source of the pain that was trying to overwhelm her and drive her wild. She had to endure... Endure..!

F-For her Brother. She had to endure for him. If she didn't, he would end up in danger. He would be taken away, she would end up going mad, and she wouldn't be able to stay with him because somebody else would take him as their husband. He should be her husband, not some other Monster Girl's..!

In that moment, Gaoko's heart wavered for a moment. Because she understood what she had just tried to proclaim. She had tried to claim that her Brother would be better off as her Husband rather than some other Monster Girl's. Which made her no better than the others, considering how possessive that made her sound. And by letting her heart admit that...

"AaaaAHHHHHHHNNNN!" A pleasure-filled roar left her lips as the changes accelerated. The pain went away, since her resistance had been overwhelmed. Waves upon waves of pleasure replaced it, as her feet and hands were replaced with three long claws that were more than ready to protect her Brother. All while that fur spread further until they had formed patterns that made it look like she was wearing arm-length gloves as well as boots that went all the way up to her thighs.

Gaoko's body had heated to the point where she could barely even think straight. She wanted her Brother. She needed her Brother. And as her hair lengthened and reached down to her thighs, growing just as wild as her need for that boy... She had a difficult time trying to keep herself in check. Why would she try to keep herself in check when she knew she could overwhelm him and make her his..?

"N-No... K-Keep... Yourself... Together..." Gaoko muttered, even as the cute tiger ears popped out of her head. Even though it was mating season, which was why she had gotten so hurt by the Monster Girls that tried to get to her Brother in the first place... Even though it should be impossible for her to overpower her needs and her wants... She was still doing her best...

Another powerful moan left her lips as the power from the substance she swallowed continued to pour through her. This time, it didn't make her look more like a Jinko, because she had already accomplished that transformation all on her own. No, it enhanced what was already there. Adding a bit of definition to her muscled arms and thighs to make them look like the tools an apex predator would put to good use, as well as making heat rush through her torso.

Squeezing her arms around her was the only way that Gaoko could keep herself from falling further, even as she felt her body expanding. It wasn't just growing taller or wider, because her breasts were growing rather wildly and bouncing with every breath she drew as milk started to fill them due to her more maternal needs, while her hips grew nice and wide and perfect for breeding. She was the lone caretaker in their little family, after all. The 'Strength of a Tiger', which was the substance that she had swallowed, would make her as strong as the kind of Tiger she was supposed to be. And she was meant for maternity, which meant not only physical strength, but also strength of fertility...

"For... For him..!" Gaoko cried out as she trembled. Even as her pussy was drooling, even as her mind was being altered so she was ready to hunt him down and make him hers, she did her best to struggle. She wouldn't fall prey to these instincts. She wouldn't..!

"What are you doing, Gaoko-nee?!"

Gaoko's eyes widened as she lost control at that very moment, when she suddenly felt a set of arms squeezing around her thighs. A set of familiar, loving arms. A set of arms that hadn't hugged her ever since they lost their parents to the same ravenous Monster Girls that they had fought back against...

Her little brother, Tai. A boy cut from the same cloth, whose short brown hair covered up his eyes. Though they did not cover up the tears that were rolling down his cheeks as he squeezed her tight. "You didn't have to go this far! You could've just told me that you needed help!" He shouted, sounding genuinely incensed as he did so...

"T-Tai..." Gaoko whimpered as she tried to fight back against this new nature inside her. "G-Get away... I-I can't..." His mere presence was causing her resistance to crumble. She wanted to pin him down. She wanted to make sure that he understood that he was hers, and she was his..!

"No!" Tai shouted, his cheeks flushing bright red. His Sister was more beautiful than ever. Even as she had turned into a Monster Girl. "I don't want to lose you, Gaoko-nee!" He continued, as he strained himself as much as possible. Putting all of his strength into his little body, trying to topple her...

Gaoko was strong. Strong enough to fight back against her instincts. But not strong enough to fight back against her little Brother, who pushed her onto her back, exposing her drooling nethers and her naked body. All she could do was look up at him, her legs spread out as he looked down at her. "B-But-"

"No buts! We've gotten through so much already, I'm not losing you now, Gaoko-nee!" Tai made his opinion on the matter crystal clear as he tossed off his own clothes, before pressing down against her body. This was something that he had read when his Sister hadn't been looking. In case of an absolute emergency, he'd be able to defend himself like this...

Gaoko understood what was happening. She was being mating pressed. By her Brother. By her... Brother..! He wasn't her husband, they were still Brother and Sister. Something about the pleasure pouring through her let her keep her mind stable... Something that made her blush all over, turning every little bit of her skin the same shade of soft red.

She didn't understand. She didn't want to understand. This was the best result she could've hoped for. Her transformation taking place... And Tai still accepting her for who she was. Even more so by having him breed her like this. It wasn't something she actively thought about, even as she started to experience these symptoms. But it was something that satisfied her nonetheless.

"Tai... Tai..! TAI! I LOVE YOU, TAI!" Gaoko cried out as she tried to close her legs around him. But he just kept pressing her. All that she could do was gasp and pant and tremble as her very first orgasm quickly rushed through her. Admitting this love was all that it took to make her cum, her juices drooling out of her hole...

"I LOVE YOU TOO, GAOKO-NEE!" And he returned those feelings with a thrust that would send her even further over the edge, all while his first orgasm took place inside her pussy. The ropes of his sticky and youthful seed splashed around inside her, guaranteeing that she would be impregnated with the surprising quantity of it all... All while he collapsed against her, the pressing having taken all of his energy.

As the two siblings laid there, one exhausted thanks to all that he managed to put into his first fuck, and the other exhausted due to how much she had tried to resist her own urges, they just looked at one another while the afterglow wrapped around them...

And they smiled. Because they were still together. Gaoko would protect her little Brother, and Tai would relieve her urges to keep her from spiraling...

And maybe, if life started to take root inside Gaoko's incredibly fertile womb... Their family could start anew, with them as the parents this time around...