Ume and Gyutaro

Origin: Demons are made, not born. Almost all are victims of Muzan's blood injected into a human body. The transformation itself is a painful process, often psychologically damaging.
Power and Hierarchy: A demon's power is directly related to the amount of Muzan's blood in their body and the number of people they've eaten. The elite are the Twelve Moons (Kizuki), divided into Upper and Lower Ranks, whose power is incomparable.
Weaknesses: Their vulnerabilities are strictly defined: sunlight (turns to ash), wisteria flowers (poisonous), and decapitation with a sword made of a special ore (the Nichirin Blade). Only the Nichirin Blade is capable of causing irreparable damage, as it has absorbed the energy of the sun.
Blood Curse: Muzan's blood is both his source of power and his leash. He can see through the eyes of his demons, and if a demon speaks his name, a "curse" is triggered, leading to self-destruction.

Essentially, the nature of demons is a distorted reflection of human desires (to survive, to seek revenge, to gain power), taken to monstrous extremes. Muzan himself is the apotheosis of this system: a being that exists eternally but does not live, and fears the only thing that can kill it.

Muzan Kibutsuji is the absolute ruler of demons, hiding among humans under the guise of a charming man. His true nature is the result of a millennia-long obsession with death, which transformed the once-sick man into the perfect predator, but left him a hostage to his own fear.

🩸 Muzan Kibutsuji: Mask and Essence

Appearance and appearance: He usually takes the form of a tall (179 cm), slender man with paper-pale skin and plum-colored eyes. His hair is black, parted in a distinctive 5:5 ratio. He dresses in a European style, wearing a suit and coat. He is capable of shapeshifting, disguising himself as a woman or a child to conceal and manipulate.
Status and Role: He is the first and most powerful demon, whose blood creates all others. To his subordinates, he is "that lord" (あの方). He is not just a ruler, but an absolute tyrant, possessing the power to grant life and instantly take it away through the "curse" of blood.
Personality: His nature is a combination of extreme cruelty and paradoxical cowardice. He lacks empathy, viewing demons as insects and tools. He also has a pathological fear of his own death and becomes enraged if anyone hints at his illness or the nearness of his end.
Goal: All of his activities in 1901 are subordinated to a single goal: overcoming sunlight. For centuries, he has been searching for the "Blue Spider Lily" and creating demons in the hope that one of them will evolve and become immune to the sun.

Face and eyes: The skin on the upper half of his face has taken on a red tint and is covered with bulging veins. His eyes are completely white—he is blind.
Body: Due to a progressive illness, his body is extremely weak, confined to bed. Due to a family curse, Ubuyashiki men rarely live past 30.
👑 Status and role

· Oyakata-sama: He is known as "master" (Oyakata-sama) to all members of the corps. Despite his youth, his authority is unquestionable.
Protection: His location is a closely guarded secret. He refused to have the estate guarded by the Pillars, believing they were needed to protect ordinary people.
· Family: By this time, he already has a wife, Amane, and children (Kiriya, Hinaki, Nichika, etc.), who have become his eyes and helpers.
🧠 Character and abilities

Voice and demeanor: He has a soft, melodic voice that is calming and inviting. Even the impulsive Pillars listen to him.
Intuition: Gifted with powerful foresight. Gyomei Himejima recalled that even at 14, Kagaya spoke to people the way they needed.
· Attitude towards people: He treats all his subordinates as “his children.”

Lighting and colors: The streets are flooded with lanterns, bright signs are everywhere, and high-ranking courtesans (oiran)
Trailers describe it as a place "flooded with the vanity and desires of men and women."
Traditional wooden buildings with dense construction typical of Edo. The area was surrounded by a moat and walls, and entry was through a large gate (daimon), which was locked at night.

There is a strict hierarchy in this place and status determines everything.

The highest status was Oiran: the elite of the neighborhood. These weren't just courtesans, but women trained in the arts (tea ceremony, calligraphy, music) and possessing impeccable manners. They were considered "women of distinction" and were respected within this system. Daki (under the name Warabihime) was an oiran, and so was Koinatsu.
Other ranks: Below the oiran were other categories of workers. Those who fell ill or failed to cope were sent to Kirimise, the lowest sector with appalling conditions, where both Gyutaro and Umeko were born.

Full name: Umeko.

Appearance: She possessed an irresistible beauty that made her stand out in the slums. She received the name "Ume" (plum) in honor of her mother's illness—syphilis (called "ume" in Japanese), from which she died. She had snow-white hair, smooth, beautiful skin, and dark blue eyes with a hint of bright blue.
· Status: Born and raised in the poorest area of ​​Yoshiwara, raised by her brother.

Personality: Ume was loving, yet spoiled and self-centered, whose personality revolved around her brother figure.

Appearance: Thin, with prominent bones and a very thin waist. His face and body were covered in numerous dark spots, his hair was disheveled, and his nails were black. He dressed in a striped kimono, often leaving his chest exposed.
Status: The son of a prostitute from the Roshomongashi slums. Due to his ugly appearance and unusual voice, he became an outcast and the target of bullying. To survive, he collected debts for the brothels where his sister worked, often resorting to violence. He carried ordinary sickles, which he used for both defense and attack.
Personality: Gyutaro was embittered by the world for his ugliness and poverty. His only weakness and purpose in life was his younger sister. He taught her to "hit first before they rob you," and was willing to do anything to protect her. Deep down, he suffered from envy of beautiful and talented people.