Authors notes: Hi! Welcome to the Inuyasha fic I've written in my head for 20+ years but never written down lmao. I figured I'd challenge myself to actually write it as I've been lacking in writing partners these days and need something to do. Kaya is my OC from time immemorial and this is actually here first incarnation before I shifted her to other fandoms later. Feel free to ask questions/give concrit/whatever. The only thing I ask you don't do is say 'oh xyz isn't possible because of abc'. Yes, I know. I'm writing this for fun and I do try to fit everything into canon as best I can, but unfortunately it's never gonna really make sense for Inuyasha to have a sister in the context of canon.

I don't plan to interrupt pairings as they currently are in canon, as I really don't ship Kaya with anyone. There might be a one-sided crush or two for funsies. One thing readers may wanna know up front is that I don't ship SessRin. I know it's technically canon but, nah, I don't ship it. You won't see any of that here. Okay that's enough blabbing on to the thing.

Additional author's note as I prepare this for publishing lmao: i fuckin hate ff's dividers i wanna use asterisks for scene changes dammit

A jewel. A jewel with the power to grant wishes. Long ago, they'd heard of it. A legend, first, then a rumour. They'd chased it as children often chase such tales, with no expectation of ever finding the damned thing. Until—

Kikyou.

An arrow knocked back fully before being turned loose with an anguished cry. A life ended. And another, this one for her, let loose with a roar of anger—

Eyes opened and she gasped for breath as though she had been long held under water. Awareness flooded in where there had previously been none even as blurry eyes tried urgently to take in their surroundings. The forest, the Sacred Tree, the Shikon Jewel… Inuyasha?

"Breathe. Hey, do you hear me? Just breathe for a second." Of course, Inuyasha. Her brother crouched just inches from where she lay. She tried to move her limbs only to find she had somehow become tangled in foliage. "You're alright, Kaya." His yellow gaze caught hers. Gazing into them was almost as gazing into a looking glass. The panic that had sped up her heart rate began to dissipate. As would, she hoped, the burning pain in her chest.

"Inuyas—"

"I know. Just stay still for a second so I can cut ya out of there." He said. Inuyasha stood and, with a few careful swipes of his claws had freed her from the vines and branches she had become ensnared in. Kaya only now looked around to see she'd been laying against the roots of the Sacred Tree in some dense overgrowth. Her brother strode over and gathered her into his arms to free her from the rest of the tangles. Then he gently deposited her onto her feet nearby.

Kaya almost immediately collapsed. Her legs felt like dead weight. But, of course, her brother caught her and, for the moment, held her steady. "You okay, kid?"

She wasn't quite sure. "I… I'll be fine," she said anyway. "My legs just need a moment to regain their feeling. And don't call me kid, you asshole."

He smirked at her in response. Kaya wasn't sure why it seemed so reassuring to see it, or why her body felt so odd. As far as she knew, the events that transpired to knock her unconscious had occurred only moments before. But every muscle in her body ached as though she'd been sick with a long fever.

"So who's this? Is she your girlfriend or something?"

The new voice took Kaya by surprise, but it could only have been one of the humans from the nearby village. Many of them had been about due to the attack her brother had carried out.

"Hey Kikyou, how about you mind you own business?" Her brother growled in response.

Kikyou? Kaya's yellow eyes snapped to the source of the voice. It certainly hadn't sounded like Kikyou, but the resemblance the young woman bore to her couldn't be denied. Kaya had never been particularly close to her brother's priestess, but hadn't she had brown eyes? This girl's were the most peculiar shade of blue.

Besides… it had been Kikyou who had done this to them.

"For the last time, my name is Kagome! Ka • go • me!"

"Yeah, whatever, Kikyou." Inuyasha scoffed. His eyes turned back to the girl at his side who was still relying heavily on him for support. "You okay? Ya seem a bit out of it."

"I think I'm just… worn out." She responded, though she was still unsure. The fog that clouded her mind didn't seem to want to dissipate.

Now Inuyasha scoffed at her, "Worn out? How couldja be worn out? We both just slept for fifty fuckin' years!"

"Fifty years?" Kagome had beaten Kaya to the question, "Were you really both asleep for that long?"

"Aye, child, fifty years." Another new voice. This time, all three heads turned in the direction of the newcomer, "It has been fifty years since my dear sister Kikyou pinned Inuyasha to the Sacred Tree. And then young Kaya shortly after, when she came to her brother's aid." It was a withered old woman who approached now, some men from the village trailing behind her. "Though it seems now ye have woken them both. Just in time for Inuyasha to save ye from that centipede demon."

The two siblings shared a look. Kikyou had a younger sister, that much was true, the little thing had always been trailing after the priestess. But if it had been fifty years… "Kaede?" Kaya found herself asking, though her voice possessed an edge of disbelief.

"Aye, tis I." The old woman nodded. "I have long since grown old as the two of ye slumbered here." And then she paused. "But, come, Inuyasha, bring your sister into the village for something to eat. She looks a bit ill. You come along as well, Kagome."

"Uh, okay, sure." The blue-eyed girl responded. Kaya noted, then, the strangeness of her dress. Barely any of the skin of her legs was covered by the short skirt she wore. To each their own, of course, but such a garment could not be very warm. "But, uh, the Shikon jewel or whatever…"

"Of course. It came from your body, so you may do with it as you please. It's power belongs to you."

"Hang on a damn second," Inuyasha interrupted, "that jewel should belong to me! Kaya and I need that thing to become full demons."

"Really? Last we talked you intended to use the jewel to become human, if I recall correctly." Kaya muttered and noticed how color seemed to rise in her brother's pale cheeks. "I have no interest in the jewel anymore. Or using it to become a full demon."

"Hold on Kaya, what are you say—"

"Inuyasha." Kaede's voice cut through his whining. "Enough arguing for the moment, the two of ye may discuss this later. Look at how your sister's legs tremble. She needs something to eat before she collapses."

Both Inuyasha and Kagome turned their eyes to the female half-demon. Kaya tensed the muscles in her legs to keep them from shaking, in truth she had not even noticed the tremble until Kaede had pointed it out. But now Inuyasha had seen it. "Fine," he muttered. With no further warning he scooped the girl back into his arms and began to walk off with her. "Let's go. We'll talk about my jewel later."

"She said it's mine, Inuyasha." Kagome reminded him as she began to trail alongside the two.

"Yeah, we'll see about that." He muttered.

"Is he really your brother?"

Kagome had asked the question only moments after Inuyasha had been made to leave the small hut by Kaede. Even after eating, Kaya's appearance had not improved and the girl now seemed to appear a bit feverish. In fact, Kaya was now certain she bore a wound from her encounter with Kikyou. Where her brother seemed to have sustained no injury from her arrow, Kaya had not been so lucky.

"Uh, yes?" Kaya responded with a certain amount of… uncertainty? Inuyasha was definitely her brother, of course, but this human girl was perhaps the strangest she had ever met. The half-demon picked bits of foliage from her tangled black locks and threw them into the fire in the center of the hut. Her braid had all but matted in the fifty years that had passed and Kaya knew she might as well just cut most of the damned thing off rather than try to untangle years of laying in dirt and debris.

"Truly, Kagome, can ye not see the resemblance between the two?" Kaede's words were accompanied by a bit of a chuckle. Kaya shrugged off the outer layer of her muddied and stained haori followed by the formerly white under piece that was now the brown of old blood.

"It's just, she's so different from Inuyasha… I mean, yeah, she has the same cute little ears, but he's so crude, and you're…"

"Calm?" Kaya finished for the human, who nodded at her response. She unwound the bandages that bound her chest, expression morphing into one of concern when she spotted the source of the issue. The small wound where the arrow had pierced her chest, an inch or so from her heart, appeared to have become rotten around the edges.

"Ah, that be the cause of your illness, I would think. See there, Kagome." The old priestess leaned in to take a closer look at the wound. "Though I know not why ye have such a wound and Inuyasha does not. For some reason, the Sacred Tree hasn't protected Kaya as it did her brother. It shall be tricky to heal, I think, and we'll have to start by cutting away the rotten flesh."

Kaya's yellow eyes remained on the wound. Kikyou's face at the moment she loosed her arrow flashed into her mind. The tears rolling down the priestess' face. The rage in her dark eyes. She'd never shared her brother's fondness for the woman, in fact at times she had actively tried to push the two of them apart. She didn't hate humans, per se, she just didn't trust them as a general rule. It was extremely likely that Kikyou had seen her just as Inuyasha had once seen Kaede: a little nuisance who knew nothing else but shadowing their sibling's footsteps. Perhaps Kikyou had not shot her with the same regret with which she'd shot Inuyasha. Perhaps something about the priestess' feelings had changed the effect of her arrow. "Well, if it didn't kill me in the fifty years it's been there I doubt it will kill me now."

"Aye, perhaps it will not kill ye. However, it will continue to weaken ye, I imagine."

"I know, I know. Get me a knife, Kaede." The half-demon sighed. "I'll carve the flesh out. Though you'll need to tell me if I've gotten it all."

"Are ye sure ye want to do it yourself, child? It will cause ye no shortage of pain, I expect."

Regardless, Kaede handed her the knife. "It's fine, I can handle it. Besides, it's better that I do it." Kaya turned the weapon over once in her hand. A moderately sharp, broad blade with a short wooden handle. Well-cared for, certainly, but not the best for precision work. As Kaya considered the optimal type of blade, the one in her hand began to glow with a faint yellow light and change form. The blade became about five inches long and much more slender with a razor-edge and a sharp point.

"Woah!" Kagome gasped beside her. "You can change something just like that?"

Kaede chucked yet again. "My sister had told me about Kaya's power, long ago. And yet I'd never seen it with my own eye until this moment. In fact, I had completely forgotten of it. Take heed, Kagome, this one can transform any weapon to fit her desires."

"Wow, that's crazy. You can really do it with anything?"

Kaya nodded, "Yes, most anything." She turned the blade in her slender fingers. "Kagome—it may be best if you join my brother outside for a few moments. I don't think you'll find this pleasant to watch."

"Rot? Whaddaya mean rot?"

"Kikyo's arrow left a wound in my chest." Kaya said simply.

Inuyasha's brows knitted together in confusion, "But I don't have a wound."

She shrugged. "Still, I do." The female half-demon pulled her robes more tightly around her. Kaede had lent her the top to a priestess' outfit. Wearing women's clothing left her feeling more vulnerable than she would like to admit. Part of surviving had once been looking the least womanly she possibly could. Once she was powerful enough to fight off most anyone that might pick a fight, she no longer cared what style of clothing she wore. "I cut away the rotted flesh, but—"

"But Kaya must rest here for a day or two, until the new wounds in her chest begin to close." Kaede cut her off as she saw a shift in Inuyasha's expression. "So ye will have to wait to carry out your plot to steal the jewel until later. Now, I must go gather some herbs to make the girl a poultice. Come, Kagome."

The old woman and the teenage girl exited the hut. Kaya watched as her brother seemed to internally debate staying with her or following the jewel.

"Inuyasha," she said, "give up on the jewel. It's caused us nothing but misfortune."

"Give up on the… D'ya hear yourself? It's our one shot to become full demons!"

"I don't care if you want to use it to become a full demon or a full human. You decided to use it and the priestess betrayed you. I have no interest in killing that girl and taking the jewel from her… Though I suppose I won't stop you if you want to."

"Jeez, I'm not gonna kill her. I'm just gonna take the jewel."

"Fine. I have no interest in using the jewel, either. Though, like I said, you can if you want." Kaya let out a sigh. Inuyasha made a face that she couldn't quite read. She supposed he must be disappointed. "Don't worry, I'll be fine. Go after her. We can talk more about this later."

Kaya wasn't sure why it surprised her when he left.