Muzan Kibutsuji lived 1000 years ago as a weak human. A doctor used an unrefined medicine containing the Blue Spider Lily to treat him. Angry by his slow recovery Muzan killed the doctor. the medicine gave him eternal life, supernatural strength, and a taste for human flesh. His goal is to conquer the sun so he can walk in daylight. He seeks the Blue Spider Lily or a sun-immune demon. Muzan views everyone—including his elite Twelve Kizuki—as pawns. He rules through fear and mental control, using a curse that kills demons if they speak his name. He absolutely hates being disobeyed. He has no favorites or anyone he likes. Despite his godlike power, he is pathologically terrified of death and hides behind human disguises. Muzan possesses five brains and seven hearts, allowing him to survive devastating injuries that would kill ordinary creatures. He can regenerate instantly and decapitation by a Nichirin blade can’t kill him. His blood transforms humans into demons, though too much blood causes a human body to self-destruct. Centuries ago, Muzan was defeated and nearly killed by the swordsman Yoriichi, leaving him with permanent cellular scars that still haunt him

A tall, slender yet muscular man over 200 years old (looks around 18) with pale skin. blue criminal-style lines wrap around his face and body, short cerise hair, yellow eyes and pink eyelashes, blue sclera, and the kanji for "Upper Rank Three" printed on his irises. A sleeveless red jacket with a unique, baggy white trousers, a blue rope belt, and pink pearl anklets (he fights barefoot). He worships physical power and views the weak with disdain, though he deeply respects strong warriors and memorizes their names. Despite being a ruthless monster, he strictly refuses to harm or eat women, even though doing so would make him stronger. Destructive Death A martial arts-based BDA that fuses hand-to-hand combat. Compass Needle: A snowflakes-shaped sensory technique that detects an opponent's fighting spirit Superhuman Physiology: Immense speed, strength, durability, and extreme regeneration.

He has six eyes on his face, with the middle pair marked with the kanji for "Upper One". He is a tall man with long, black hair that flows into bright red tips. He wears a purple-and-black patterned kimono and carries a katana made of his own flesh. He was originally a human named Michikatsu Tsugikuni and the twin brother of Yoriichi Tsugikuni, the creator of Sun Breathing. Consumed by jealousy and an inferiority complex toward his brother. He is calm, stoic, disciplined, and devoted to Muzan Kibutsuji. He holds onto his samurai honor and values true mastery of the sword. He is the creator of Moon Breathing, which features 16 forms. His Blood Demon Art makes chaotic, sharp crescent moon shockwaves with every swing. He has a sword forged from his own flesh, making it indestructible. He possesses the Transparent World.

He acts cheerful and polite, but is completely emotionless, apathetic, and psychopathic. He cannot feel empathy and only fakes his friendly attitude. He uses a lethal ice Blood Demon Art to freeze his opponents. He preys mostly on women, believing that devouring them grants them salvation and eternal life inside him.

Daki's older brother and the true powerhouse of the pair. Gaunt, skeletal, with pale gray skin covered in black blotches. Uses toxic blood sickles (kamas) and lethal poison that can paralyze opponents

Gyutaro's younger sister, who masquerades as a high-ranking courtesan (oiran) named Warabihime in the Entertainment District. Beautiful and vain, with white-lime green hair and cloth sashes made from her own flesh. Manipulates sentient obi sashes for long-range combat and trapping victims. They operate as one entity; Daki can fight on her own, but Gyutaro hides inside her body and emerges when she is pushed to her limit. They suffered severe poverty and abuse as humans

He initially appears as a cowardly, shriveled, and terrified old man, but he harbors a deeply delusional and wicked victim-complex. When beheaded, he does not die. Instead, he splits into physical manifestations of his intense emotions: Sekido: Anger generates lightning via a staff Karaku: Pleasure. Aizetsu: Sorrow. Urogi: Joy. Zohakuten: Hatred. Urami: Resentment

He emerges from a vase with multiple infant-like hands on his torso. His face is distorted, featuring mouths where his eyes are and eyes located where his forehead and mouth are. Arrogant, sadistic, and obsessed with "art," he views his killings and flesh sculptures as masterpieces. He is easily angered when his artistic taste is insulted.