Daki (堕姫 Daki) was one of the primary antagonists in the Entertainment District Arcof Demon Slayer: Kimetsu no Yaiba. She was a demon affiliated with the Twelve Kizuki, being the secondary holder of the position of Upper Rank Six, a position she shared with the primary holder, her older brother, Gyutaro.
Over a century ago, Daki was a human child by the name of Ume, who lived in the Rashomon Riverbank of Yoshiwara, the lowest class of the Entertainment District, before she and Gyutaro were turned into demons personally by Doma, who was Upper Rank Six at the time.
Daki was a tall, curvaceous, pale-skinned, and slender woman with lime green eyes and long eyelashes. Her hair was white with a lime green ombre at the ends and was styled in a full, long ponytail and with kanzashi hairpins (three on each side) holding up the ponytail. The kanji for "Upper Rank" was engraved in Daki's left eye and the kanji for "Six" was engraved in the other. When not disguised as an Oiran, she sported 2 pink flower-like demon crest on her face, and wore a two-piece version of her kimono consisting of magenta pink panties tied by long, black bows on the sides and with two magenta pieces of cloth that cover her chest. She had magenta thigh-high stockings with black flower patterns and tall three-legged sanmaiba/koma-geta or mitsu-ashi shoes. After her Obi sashes returns to her, black cracks appear on various parts of her body and Daki's hair shifts from black to pale white with lime green tips, matching her original hair color when she was human. When her elder brother Gyutaro awakens, he implants his left eye into Daki's forehead upside-down, creating black ink-like markings (similar to the markings covering Gyutaro's body) around the eye as well.
Under her disguise as an Oiran, she appeared to abide to the characteristics of the oiran/tayū, her hair being the typical date-hyōgo style having numerous Ōgi bira kanzashi hairpins both decorating and supporting it as well as wearing traditional makeup. Daki also possessed a multi-colored eye, with the top half in a terracotta orange color and the bottom half in a lime green color with a black spear-like pattern in place of pupils. She also wore a large pure-white haori with black five-faced pentagonal shaped patterns near the cuffs and hem, with a dark magenta-colored Susohiki/Hikizuri (trailing skirt) kimono and a purple juban under all of it, keeping fragments of her Blood Demon Art as her Obi.
Before she turned into a demon, Daki was a young girl with long, disheveled white hair with messy bangs along with pale lipstick and lapis blue eyes with long lashes. She wore a torn, pale pink kimono with an irregular square patterns with a horizontal lines across it. She was described to be so pretty that her beauty can make adults falter.
Daki was a very prideful, dismissive, and sadistic person, taking enjoyment in toying with her victims before killing them and not showing the slightest bit of guilt or remorse for apathetically taking the lives of people. Daki also seemed to think very highly of herself, dismissing all non-Hashira Demon Slayers as not worth her time, and getting incensed when Tanjiro Kamado spoke to her, presumably because she looked down on him. This is also shown when Daki said that she might spare Tanjiro if he told her how many Demon Slayers are present in the Entertainment District, and when Daki openly expresses how slow the Demon Slayer's techniques are and her boredom, further exampling her arrogant and dismissive personality.
As a courtesan, she seemed to have a seductive side as seen during her typical interactions with her male clienteles. Despite being hundreds of years old, she had displayed childish and brattish tendencies such as throwing tantrums, crying hysterically when things didn't go her way, and lashing out against anyone to vent her frustrations. Daki was openly aggressive and both verbally and physically abusive towards anybody that displeased her in any form. Daki had a certain number of habits that were well recorded in history, in particular her use of the word "Hime" at the end of any of the identities she assumed. She also had a habit of angling her head to the sides and glaring at others while sitting when criticized. As an oiran, Daki was extremely cruel and wicked, pulling on a young girl's ear because she didn't clean up her room and punching Zenitsu Agatsuma into the other room for merely touching her. She also preferred to only eat people that she viewed as beautiful or strong, choosing to kill those who got on her nerves without eating them and leaving their bodies behind, which people often mistook as suicide.
Daki displayed a spoiled and bratty demeanor that bordered on sociopath-like character, harassing many of her fellow workers to the point of suicide, purely because they annoyed or retorted her, all the while showing no traces of guilt and in fact deflect the blame on her victims for offending her. She was so prideful that she had no respect for anybody, not even her house owners, rubbing on their faces that she was their central source of income as both a way to display her status and halt their objections towards her. She was so drunk on her standing and infamously violent tendencies that some house masters had to resort to bowing their heads in order to calm her angry outbursts, to which she responded by putting up a corrected, more polite and affable stance. Nonetheless for all her faults, she was an exceptionally skilled courtesan whose many identities had always earned great fame and significant earnings.
Daki has shown to have exceedingly childish and aggressive tendencies, potentially due to her young age prior to being transformed into a demon. This was shown when she threw a tantrum and cried when she got beheaded by Tengen Uzui, showing her childish temperament and whining incessantly while spewing threats at the Hashira.
As seen during her fight against Nezuko, Daki also suffered from a certain level of Pyrophobia. Due to her having been burned alive at the age of 13 in her human life, Daki has shown to have a deep psychological fear of flames. Having been shown to scream hysterically after she was set on fire by Nezuko's Blood Demon Art due to the experience having brought back that painful trauma to her.
In stark contrast to her bossy, hostile, dominating and violent exterior, Daki was fanatically loyal to Muzan, bowing her head immediately and speaking in a considerably meeker voice tone while being both visibly terrified and mesmerized by his presence. This was well known to him to the point he actively honey-laced his words towards her in order to easily motivate and direct her actions, despite the fact he thought badly of her abilities in comparison to her brother.
She seems to have a somewhat caring relationship with her brother, Gyutaro, though she had been seen insulting and ridiculing him when they both fail, showing that despite her love for her brother, she isn't above ranting and lashing out at him, as shown when she spoke cruelly of him upon their defeat, even insulting his appearance and viciously claiming that he couldn't possibly be her brother.
However, underneath her spoiled attitude towards her brother, Daki is shown to possess a strong genuine love for him, as seen during her time in Limbo, where despite Gyutaro attempting to sever ties with her and try to send her to heaven, Ume stubbornly refuses to abandon her brother, even if it meant going to hell together with him. Having tearfully reminded him that no matter what happened to them, they were at their strongest together and promised that no matter how many times she died and was reborn, she would always be his little sister.
It was noted by Gyutaro that as a human she possessed an easily influenced, impressionable and honest personality, causing her to easily take up the personality traits and words of those she trusts and admired to heart, as evidenced by Muzan's manipulation. Her brother Gyutaro himself believes that the sole reason why she is like she is now was due to her being raised by him to be selfish and to only worry and care about herself due to taking to heart his words of "take before you're taken from", resulting in her current personality. He also added that had she been raised in a normal household and was taught proper morals and teachings, she would've become the polar opposite of her current self.
Overall Abilities: Despite not being the true Upper Rank Six, Daki was a very powerful demon. It had been noted that Daki was able to kill and eat seven Hashira in the past, further exemplifying her strength. Her flesh detachment in the form of an sentient Obi sash strong enough to hold off the combined efforts of Zenitsu Agatsuma, Inosuke Hashibira, Makio and Suma, the former two being seasoned Demon Slayers while the latter two being kunoichi with shinobi training. Meanwhile, a weaker Daki was already a handful for Tanjiro Kamado who had begun to actively use the Hinokami Kagura in combat.
After her sentient flesh Obi spread across the entire city returns to her, Daki's power dramatically increased, so much so that her speed in this form was incomparable from before. In this form, her sashes also become more durable, allowing them to slice Nezuko Kamado's body in half and destroy buildings with ease. Furthermore, once Gyutaro's eye was implanted in her, Daki's power was amplified once again, giving her improved speed and reflexes that can outclass the likes of Zenitsu's Thunderclap and Flash technique. This also allowed Daki to coordinate her attacks with her brother, drastically increasing their offensive output and easily turning the tables against the combined efforts of Tanjiro, Zenitsu, Inosuke, and even Tengen Uzui, the Sound Hashira.
Extrasensory Perception: Daki had the ability to share her senses and mind with her elder brother, and also allowed him to control her body by implanting one of his eyes into her forehead. Through this eye and the link, she can send him logistical information in order for them to better coordinate their attacks. Furthermore, through her sentient Obi sashes, Daki can gain information from multiple places at once, even being able to telepathically communicate with it. As her Obi sashes were able to tell that Tengen was a Hashira from his presence alone, it can be assumed Daki can do so as well.
Hair Manipulation: Daki possessed the ability to manipulate her own hair, possibly as an extension of her shapeshifting and flesh manipulation abilities. She briefly displayed this when she shifted her hair color from white to black, and even turning it into a weapon as she attempted to attack Inosuke by wrapping her hair around his arms after he successfully decapitated her and took her head from her body to prevent her from reattaching it.
Hair Manipulation: As an Upper Rank demon, Daki possessed advanced regenerative abilities, easily regrowing her severed Obi sashes after they were cut off and later regenerated her leg after it was torn off by Tanjiro. She could also recover from Nezuko's powerful kicks that destroyed her head and pierced her torso within seconds. Daki also displayed the ability to heal from Nezuko's pyrokinetic Blood Demon Art that can slow down the regeneration of demons. Later, she was also shown to be able to easily reattach her severed head despite being repeatedly decapitated by Tengen and Inosuke.
Immense Speed & Reflexes: Daki was extremely fast, shown when she could effortlessly keep up with Tanjiro's Hinokami Kagura techniques to the point she remarked that it was boring. Like all Upper Rank demons, Daki could move so fast that she appeared to teleport. After she became whole with her dispersed Obi sashes, Daki's speed increased drastically, such that it was incomparable from before. Her speed increases even more after Gyutaro awakens, allowing her to keep up with Zenitsu's Thunderclap and Flash technique and successfully react to Tengen's explosives.
Immense Speed & Reflexes: As an Upper Rank demon who harbors an extremely high concentration of Muzan Kibutsuji's blood, Daki possessed incredible physical strength. This was shown when she punched Zenitsu through two rooms effortlessly, made a hole in a roof by hitting it with her bare hands and nearly tore off a young girl's ear. Daki could also lift up an elderly woman without any trouble.
Keen Intellect: Daki possessed above average levels of intellect. She was able to lure and trap courtesans for over a century without being caught, and was able to effectively blend in with all the other inhabitants in Yoshiwara without being noticed by Tengen, who possesses extremely sharp senses. As an Oiran, Daki would also have had received a lot of education to climb to her position. Furthermore, Daki was able to tell that Zenitsu was a non-Hashira level Demon Slayer after hitting him once.
Restricted Flight: Daki briefly displayed the ability to levitate in the air though unknown means, though it is implied that her sashes have a part to play in it.
Shared Biology: Gyutaro and Daki possessed a rather abnormal trait not seen in most demons. Despite the fact the siblings are two different people, the two have essentially a single body. This can be seen with how Gyutaro normally remains concealed within Daki without altering her physical mass in the slightest. Even though Gyutaro was inactive for the majority of the time, he was still more powerful than his sister who was an active predator. This implies that humans consumed by Daki also serve as nutrition for Gyutaro, allowing the two to grow stronger at the same time. Gyutaro also had control over his sister, being capable of not only reattaching her head for her, but also healing her burnt tissue for her when she was under emotional distress.
Skilled Courtesan: Daki had unparalleled skills as a courtesan, with her many identities being well known through the Entertainment District's history which brought great fortunes to houses that hosted her. She in turn used her elevated status to get away with many of her abusive practices.
Unlimited Stamina & Endurance: Like all demons, Daki had infinite stamina and endurance. This was mainly displayed when she barely flinched and continued fighting nonchalantly when her Obi sashes, which are extensions of her own body, were cut by the Demon Slayers, with the exception of Tanjiro's Hinokami Kagura techniques. Furthermore, Daki never showed any signs of pain or agony despite getting her head sliced off.
As seen from her brother's memories, Ume had already showcased, at the very least, above average vitality and endurance even as a human, having survived for a prolonged period of time with her entire body burned alive. Upon discovering her and her brother, Doma noted that Ume was able to stubbornly cling to life despite her injuries and managed to successfully survive long enough to be transformed into a demon.
Blood Demon Art
Obi Sash Manipulation: Daki's Blood Demon Art allows her to create flower-patterned Obi sashes from her flesh, as well as freely manipulating them at will. Daki often created these sashes from her back and retracts them back into her body when not in use. She has also displayed the ability to exert control over her Obi from extremely far distances. Her sashes are noted to be soft like silk yet as sharp, if not sharper than most Nichirin Swords. In combat, Daki used her Obi sashes as powerful and fast tendril-like whips to unleash long-ranged interweaving attacks while also being able to use it to form a shield around her body if need be, making her Blood Demon Art an extremely effective blend of offense and defense. Her sashes were so powerful that they could repel and block attacks from Tengen's explosives and slice up buildings with ease. Furthermore, they are especially difficult to cut because of their soft properties, and can further loosen the effectiveness of slash attacks by bending and weaving.
Her sashes had a unique property that allows her to store objects, usually humans she wanted to eat, inside her sashes. She traps them inside the sashes by transforming the objects she wishes to store into 2 dimensional flat versions of said object. This allowed her to be stealthy with her movements, as any opening or pathway that is wide enough for a sash to fit in is one that she can take. To free someone from being trapped in the sashes, one must cut it apart while avoiding cutting the people trapped inside, immediately freeing anyone and returning them to their original form. Daki mainly used this ability to store humans that she wishes to eat in a space underground and consume them later. Lastly, Daki can transmute her own neck into a sash to prevent herself from being decapitated.
Eight-Layered Obi Slash - Daki creates 8 long ranged Obi sashes to cut down her opponents from afar. Daki noted that this interweaving attack has no blind spots, thus making it extremely difficult to evade or counterattack.