Association with Butterfly Mansion elicits poison use?

Future Phoenix Form Names:?
-Burning Sky Dance: Something involving actual outward pyrokinesis, possibly something inspired by Flame Form 4 mixed with Form 5?
-Tailwind of the Sky God: Focused flame expulsions from a user's weapon or limbs that act as thrust to enable flight? Possible Phoenix Form 4 or 5 candidate, since this seems fairly straight-forward in terms of elemental shaping.
-Breath of Life/Merciful Phoenix Tear?: A technique that through closely syncing the user's breathing with a subject (potentially via mouth-to-mouth resuscitation-type contact?) allows them to extend the effects of Phoenix Form 2's accelerated healing to another person, guiding their body into performing the technique even if the subject is otherwise incapacitated? Potentially extremely straining on the subject; may save their life in the immediate but may also be more likely to induce the stress that lowers their lifespan as recompence. This downside is especially dangerous if the subject also has a Demon Slayer Mark.

Salamander Style?: A style mixing poisons with fire by ingesting toxic materials and mixing them with flames inside the user's body before expelling them in Breathing techniques?
-Form 1 Crouching Tiger, Hidden Wisteria: Consuming wisteria flowers beforehand, the user imbues them into the cloak of flames created by the 5th Flame Form, creating a new technique that slashes the target with poisonous flames, creating wounds that demons find more difficult to heal.

'Rengoku Hinotora'
'Rengoku Hinotora'

^{P e r s o n a l i t y} :

Hinotora is, in a word, "irreverent", having little respect for tradition or hierarchy. Strongly self-assured to the point of almost being arrogant, she is rather rude by Japanese standards, rarely using honorifics, calling others casually by given names -or nicknames- or just shamelessly voicing her discontent aloud, even in formal settings. While not fundamentally opposed to not making a problem of herself, Hinotora resents being expected to conform to the expectations of anyone but herself. In her eyes, the only approval she truly has to meet is her own, and as long as she's living life the way she has decided is correct, that's all there is to be said about it. She is the sort to revel in exertion, to exhibit the tendencies of a battle junkie once her blood gets pumping.

Her apparent brashness, however, clouds the true cunning in her nature. At heart, Hinotora is a deeply ambitious woman, tantalized by the idea of self-improvement and strength; yet, she is also steadied by a keen sense of self-preservation. Contrary to many -if not most- Demon Slayers, who glorify the ephemerality of life and the meaning in sacrifice, Hinotora has no intention of dying, not any time soon and ideally not any time at all. To her, sacrifice is cowardice and weakness, to take the easy way out, and true strength is to defy the dying light until the bitter end and beyond. As something of a fan of Western culture and media, she once encountered a quote that struck her poignantly: "Dying is easy, young man; living is harder!" Having internalized this concept, Hinotora believes true strength is continuing to live and fight on no matter what, because you're no good to the world dead. And no matter how many you save in the present by dying, you could have saved far more by living on in the long run. Yet, conversely, she does not scorn those that die simply because they were weak; in her eyes, the truer sin is not dying after having given your all but forgoing survival whilst having any other option.

This kind of ideology, needless to say, stands in stark contrast to much of what the Demon Slayer Corps believes, almost seeming to mock their history in how it interprets the pursuit of justice through a lens that many demons could appreciate. But it's far from the most controversial stance Hinotora holds. In fact, as far as actual demons are concerned, she views them as no different from humans spiritually. In her mind, it is only right to dehumanize others based on "inhumanity" as a concept, not physical status. "Humanity" to her is a way of life, lost or gained by deeds and choice, not by nature, and she is open to offering demons -particularly young ones- some level of slack in consideration for their biological murderous instincts, provided they show a willingness to rise above them. Conversely, she does not view the human and demon conflict as a matter of black and white and sees no issue with good demons killing evil humans. Despite this, she is not by any means blind to the nature of most demons, who more often than not selfishly abuse their powers to murder and consume the undeserving, and she is doesn't hesitate in punishing the truly unjust and mercy-killing those too weak of will to resist their instincts.

At her core, though not arrogant enough to shun working with others, Hinotora is a girl who found a certain strength in isolation, who didn't crumble under the pressure of others' expectations but rose up to defy them and carve her own path. Despite her seemingly selfish ideals, however, the one thing the Rengoku Clan truly instilled into her was a genuine value for justice and the pursuit of a better tomorrow. Dazzled further by tales told in many a fiction she buried her nose in as a child, along with tales of legends in Demon Slayer history, Hinotora idealizes the concept of heroes and -in contrast to her outward tendency to dry cynicism- wants to stand for what is ultimately right, no matter how much her methods might disagree with the opinions of the majority.

The only person Hinotora seems keen to offer actual unvarnished respect as a matter of deferential authority is the head of the Butterfly Mansion, Yushiro, who she refers to as "Sensei", admiring him as the pinnacle of demon-kind's potential for coexistence with humanity and as a person of otherwise genuinely respectable intellect and legacy. She still finds his fits of annoyance amusing and is not above harmlessly needling him, having certainly attempted to pester him for stories of legendary events he was involved in.

^{S h o w a S e c r e t} :
The circumstances of Hinotora's birth were contentious in no small sense of the word.

Her mother, Rengoku Taiga, a Flame Breathing demon slayer, had conceived out of wedlock during a night of emotional fancy with a handsomely mysterious stranger, and while this would have already been scandalous enough, what would turn the matter borderline heretical was when the father of Taiga's child chose to make himself known. Having apparently kept tabs on her in the aftermath of their dalliance, he approached Taiga on a dark, moonlit night and revealed himself to be a demon, and it was at that moment that she realized with horror that the man before her was none other than a Blood Moon, the only demons that could sire children. And it was then with a terrible "kindness" that the Moon attempted to turn both mother and unborn child with his blood... and failed.

The aftermath of the attempt and the terribly weak state it left the mother in would leave it an open secret that the circumstances of the upcoming birth were the union of a demon and a human, and more ardently, it was advised that the fruit of the union be removed before it could blossom, such was the shamefulness of it. Yet, the soon-to-be mother rejected such advice, and for her ardent determination, she was rewarded with a healthy baby girl... who she'd not live long enough to raise.

This was the world Rengoku Hinotora arrived into, orphaned at birth and perceived rather unfavorably for the circumstances of it.

To the Rengoku Clan's credit, despite Taiga's more immediate family shunning and otherwise outright disowning her child for the walking stain on their reputation that she was, Hinotora was not disbarred from the same opportunities any other child of the clan had, having all her basic living and educational needs met. However, the rumors surrounding her heritage isolated her socially growing up, leading to some amount of ostracization, and she would end up not internalizing or properly embodying the Rengoku Clan's ideals, becoming a rebellious punk of a girl.

Despite being indoctrinated into Demon Slaying from nearly the moment she could walk (perhaps as a form of "penance" for her existence and "proof of worthiness" in certain eyes), Hinotora did not respond to harsh training and attempts to mold her into a simple cog-in-the-machine weapon with meekness and humble obedience, but instead earned scorn for being a snarky little shit that offered no respect to others that wasn't "earned", displaying a precocious awareness even early on that she knew she was being treated unfairly and had no intention of taking it lying down. Her increasingly irreverent behavior led to her being viewed as ungrateful towards her benefactors and occasionally heretical for the curiosity she showed towards "deviant" and "problematic" knowledge. This dissonance in values further ostracized her, especially once she developed the Phoenix Breathing Style rather than "course correcting", earning her even greater scrutiny for the "shamefully selfish and dishonorable" mindset emphasized by her new Breathing Style.

In the end, having felt as though she never truly formed bonds with her own family, Hinotora would take the opportunity shortly befoe she reached her age of majority to transfer away from the strict and traditional Kyoto branch of the Demon Slayer Corps -and subsequently, the Rengoku's larger sphere of influence- to study and fight abroad with the far more flexible and lenient Tokyo branch. There, she encountered an environment so diametric to the one she had left that she even found herself fighting alongside demons as allies every now and then.

As it turned out, the Tokyo branch of the Demon Slayer Corps paid much more respect to a niche element of their Corps' history, the reality that in their direst time of need, they had received aid from other demons against Muzan, the reality that demons could -if given the chance- reject their murderous instincts and coexist peacefully with humans. This understanding was something Hinotora found to resonate with her on a level she hadn't realized was possible. And as she continued to sharpen her skills on the rather more "intense" Tokyo territories in the demon vs slayer conflict and studying the history of said conflict and how it came to be, she found herself silently asking a rather poignant question...

Aren't humans and demons just two sides of the same coin, after all?

Not much more than two years ago, shortly after she'd moved to Tokyo and begun delving deeper into a medical education, that same question was brought into even sharper relief, as when encountering a demon during her "civilian hours" that nearly bested her due to attacking her while she was unarmed, Hinotora discovered that her blood was not only toxic to demons but had the capacity to convert them back into humans. Instead of being disturbed by the potential implications this might have for her own status, however, Hinotora was ecstatic, beginning to study the phenomenon deeper and consider the ways this could be used to further deepen the development of her Phoenix Style.

Nowadays, if you were to visit the Butterfly Mansion, perhaps you might encounter her occasionally, a young woman with jet-black hair and a dark red long-coat, her golden eyes curled into sharp coy smiles, as she casually engages in comradery with an allied demon. In recent years, Hinotora has slowly become a more common face amongst the most intellectual faction in the Demon Slayer Corps, earning her keep in performing experiments in new ways to fight demons, and from a mundane angle, "Doctor Hinotora" is slowly gaining a reputation amongst secretly Butterfly Mansion backed hospitals as a young rising star in the medical field.

Also fairly recently, Hinotora has been scouted as the Tsuguko of the Dragon Hashira, Jae-eun, and while she was initially wary of the offer of a many who so often wore a flowery mask, she has since found the arrangement between them to be surprisingly and pleasantly amiable.

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'K o k y ū'
'K o k y ū'

^{F l a m b o y a n c e} : Hinotora is a practitioner of Flame Breathing Forms 1-5 and is capable of the advanced form of Total Concentration: Constant Breathing. However in terms of the pure Flame Style, her proficiency lacks compared to her true specialty, the Style she developed as one more suited to her philosophy, Phoenix Breathing. It is for this reason and her general estrangement from the Rengoku Clan that has led to her never learning Flame Breathing Forms beyond the 5th.

Phoenix Breathing or “The Breath of the Phoenix” is a derivative offshoot combination of Flame Breathing and Total Concentration Breathing, which could be seen as heretical by many Demon Slayers, as it emphasizes a philosophy of "ascension" and the pursuit of survival, idealizing the concept of "stoking an eternal flame", rather than burning brightly and burning out. In a sense, it rejects the idea of sacrificing oneself in the pursuit of one's goals, instead emphasizing living to fight another day. For, after all, what point is there in fighting for a better world if you don't live long enough to enjoy the fruits of your labors, right? Regardless of this rather selfish premise, however, there is an undercurrent of honor, an idea that reckless sacrifice is -in itself- cowardly and that living to fight on guarantees the chance to save even more lives in the long run. In Hinotora's eyes, a true Phoenix may burn eternally, but they burn always for Justice. A true Phoenix shall Set Their Heart Ablaze... and always rise from their ashes.

Mechanically speaking, the Phoenix Style takes advantage of the great advancements in (semi) modern medicine and biological knowledge to create a foundation that surpasses its origins. It combines Flame Breathing with advanced forms of Total Concentration Breathing, primarily those of the Recovery type, and puts a focus on cultivating that power internally, reinforcing and enhancing the user's foundations to allow them to achieve a physicality and endurance comparable to Demons. Indeed, if this Breathing Style has but one definitive goal? It is "to become inhuman without rejecting one's Humanity".

Compared to other Styles, the current forms of Phoenix Breathing are typically less "special elemental moves" and more a series of stacking enhancements. This focus on "improving one's foundation" means that, on an external level, a user showcases very little "elemental power" compared to other styles until at least beyond the first 3 Establishing Forms, which act as the cornerstones for the entire style. The Style treats the user's body like an engine, pressurizing energy inside one's nerves and muscles to achieve explosive speed and power. All the while, the user's cells are treated as growing batteries, storing energy to be unleashed later.

As an actual sword style, Phoenix Breathing emphasizes a wide, deft swings with a strong sturdy blade. To fight as a Phoenix is to be a glorious burning bird of prey, swiftly closing the distance with a target, engaging in a relentless offense, before deftly retreating with equal agility to avoid retaliation and begin the whole cycle anew. Mobility is a key element and highlights a need for strong reflexes and quick thinking, along with making the user at home with executing midair maneuvers. It is a fighting style that creates brute strength through velocity and dexterity and -if practicing its Forms properly- provides in and of itself the necessary physical ability to do so.

✧ Form 1: Furnace Breathing - The first step in the style emphasizes purging impurities and reinforcing one's foundation. Acting as a variant of Recovery Breathing Method laced with cleansing Flame, the user stokes an internal fire surging with the "breath of life", flushing their body free of invasive elements (like poison, disease, etc) and energizing their cells with revitalizing energy and renewed stamina, providing them near limitless endurance. In practice, this form is meant to be used constantly, with every other part of the Phoenix style branching off of it. Side effects of long-term usage of this form include an overall improved immune system and general health along with increased longevity due to gradually restoring the expended capacity of the user's cells to naturally replicate.

✧ Form 2: Flaming Rebirth - As the style's mainstay recovery technique, the second form utilizes an improved form of the Enhanced Recovery Method. Whilst the first form focuses more on gathering and maintaining energy, this form releases that storage in a burst of restorative activity. By focusing their awareness and manipulation of their body, the user is able to detect and heal or otherwise mitigate even hidden internal injuries. By manually prompting their cells into replicating and forcibly accelerating the body's natural recovery systems, at the upper end, the user can manage a form of slow but combat-effective regeneration, limited -granted- to healing only injuries they could have otherwise theoretically recovered from naturally. Lesser uses of this technique can include slowing the circulation of poisons, seizing control of muscles to prevent organs from falling out or even halting bleeding by near-instantly coagulating blood or cauterizing wounds with the user's own flames. This form, once learned, allows the user to train much faster than normal, greatly increasing training time due to how fast their bodies can heal after even the worst and most insane training.

✧ And while this may mostly just sound like normal ERM on the surface, what the Phoenix style truly improves the technique with is the capacity to utilize it even when the user cannot breathe, forcibly drawing on reserves of vitality to induce emergency recovery and allowing them to restore vital bodily functions even in positions where a normal human would suffocate. However, performing the technique without breathing causes immense strain on the body, to the degree that it even decreases the user's lifespan, counteracting the improved longevity of the first form with overuse. Usage of this technique carries a glint of elemental power, as since the recovery is laced with a release of stored Flame energy, the user's wounds may occasionally spew flames when they "cauterize" in a burst.

✧ Form 3: Fire Bird's Spirit - Still staying true to much of the Style's "ladder"-like progression, this form is not an island, but rather an extension of prior forms. Once the body's foundation has been established and protected, this form is used to properly reinforce and enhance it. With this form, the user learns to constantly reinforce their body with the explosive power of flames, greatly enhancing strength, speed, reflexes and overall senses beyond the normal levels of Total Concentration Breathing. This form is learned third in the order of things, since without the second form, this form carries a great risk of burning one's own body up from the inside out without any way to address internal injuries. Because of this, this style could only be developed and trained by Hinotora once she was confident she had mastered both RCM and ERM, and as such it currently remains the third and final of the Phoenix style's maiden techniques.

✧ Usage of this form creates great heat inside the user's body, keeping them warm in cold environments whilst warding off extreme heat through the way the process of training the technique tempers the body against the opposite extreme. The process of learning the technique includes heat management usage of TCB in order to avoid overheating the body, and it's not uncommon for the user's breath to escape them in steaming exhales. Any damage this form does cause to the user's own body is typically swiftly rectified by the use of the prior two maiden techniques of the Phoenix Style.

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'N i c h i r i n'
'N i c h i r i n'

^{B l a d e W o r k} : Hinotora carries a blade glinting with a fiery orange hue, representing the explosive flames lurking beneath her skin. Unlike most Demon Slayers, she does not wield a traditional katana; instead, she carries a longsword of European shape, bringing to mind images of armored knights astride gallant steeds. A bold design emblematic of flames in a spiral of gold and orange runs down the center of the blade as well.

Yushiro Concealment Talisman: A standard-issue talisman used to cloak the presence of her sword and other demon slaying equipment while not in combat, allowing her to always be armed even in public without drawing suspicion.

Medical Supplies: Carries a small pouch of utilities for treating harm, including bandages, stitches, medical tape, painkillers and some other odds and ends. In the case of a situation where she has time to prepare for immense trauma level injuries, she can requisition an ambulance from a Butterfly Mansion backed hospital and load it with more heavy-duty equipment.

Kasugai Crow: Hinotora's assigned crow is a female that displays a more eloquent grasp of speech than the average talking corvid and who has grown quite the ego in part because of that, taking pride in displaying abnormal skills. Professional and smugly composed in most cases, she is a bird that has been referred to as "cat-like" in the past. Hinotora trained her to deliver messages quietly, rather than bellowing announcements to all and sundry in the area.

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^{U n i q u e T r a i t s} :
✧ Sweet Tooth: Really likes her sweets. Often can be seen casually chewing on some form of candy, particularly gum or lollipops.
✧ Biology Major: Hinotora, supplied with the more "modern" education of the 1980's, aggressively pursued knowledge of the human body in the development of the Phoenix Style. Having worked closely with the Butterfly Mansion since the discovery of her Sakasachi blood, she has also done much study on human and demon biology. Her refined sense of her body gives her an upper hand in using Total Concentration Breathing techniques to manipulate her body in unconventional ways compared to the average Demon Slayer, and her knowledge of medical techniques, drugs and poisons is extensive enough to make her an able field medic and surgeon.
✧ Indomitable Will: Like many Demon Slayers, Hinotora possesses an ironclad will and spirit, refusing to give up and remaining lucid and focused even when under immense pressure and pain. As a result of her harsh training methods along with no small number of brutal demon encounters, she is quite familiar with pain and able to largely ignore it.
✧ Eye For Bullshit: Due to being raised in an environment filled with people that (in her words) "masked contempt as righteousness", she has a rather finely honed sense for when she is being deceived or misled. Though by no means does this imply she is a mind-reader or any such nonsense, it does mean she is very difficult to put up fronts around. "Masks" rarely go unnoticed, and once her suspicion is aroused, the possibility of her determining what is hidden becomes much higher.
✧ The only reason Hinotora doesn't have tattoos is that the development of Phoenix Form 1 resulted in the "purging of impurities" in her body, including any ink.

✧ Special Trait: "Blessed" (Sakasachi) Blood - As a result of her abnormal heritage, despite by all other accounts being a perfect picture of humanity, Hinotora's blood carries a special property which allows it to digest and assimilate demon genetics, "converting" them into healthy human biomass instead. Because of this, unless she makes a conscious effort to suppress her biology's natural instincts with some form of TCB, Hinotora's blood makes her highly resistant -if not immune- to the process of demon conversion. And conversely, even perhaps far more disconcertingly, it allows her blood to be used as a cure and poison both that is capable of converting demons... back into humans. This extremely rare -if not entirely unheard of- phenomenon has hence been classified as "Sakasachi Blood" by the Butterfly Mansion.

• At present, this property is relatively recently discovered and largely unexplored and unrefined, leaving it only capable of completely reverting a demon that was changed no longer than 3 days ago. Beyond that point, it is merely a highly potent -though not necessarily deadly- poison, making Hinotora's blood effectively toxic to demons.
• It is unknown what would happen to this trait if Hinotora were to be transformed into a demon. Would it somehow be retained? Would it be inverted? Perhaps the truth will never be known.