Demons (鬼, Oni) are a race of immortal creatures that feeds on blood to survive and become stronger with each human they devour. All demons were formerly humans who lost most of their memories and traces of humanity after drinking or being injected with Muzan's blood, becoming his servants and sharing their vision and thoughts with him. Demons possess enhanced senses, regeneration, and physical abilities. Higher demons are also capable of casting powerful spells called Blood Demon Arts (血鬼術, Kekkijutsu), which are unique to each demon.
Demons are weak to sunlight, which fatally turns them into ashes upon being exposed to it. They can also be killed by decapitation with special swords used by the Demon Slayers called Nichirin Swords (日輪刀, Nichirin Tō). Demons are also vulnerable to wisteria flowers, avoiding places where they are abundant and wisteria extract being poisonous to them in sufficient doses.
Muzan Kibutsuji
- Voiced by: Toshihiko Seki[32] (Japanese); Greg Chun[33] (English)
- Muzan Kibutsuji (鬼舞辻 無惨, Kibutsuji Muzan) is the first and strongest demon in existence, as well as their ruler. He was originally a sickly young man who lived during the Heian period, who was turned into a demon as a result of an experimental treatment intended to save his life. Since then, he has dedicated himself to using his blood to sire demons in an effort to create a demon immune to sunlight. This goal motivates him to attack Tanjiro's family in an attempt to turn them into demons, and after Nezuko, the sole survivor of the attack, manifests an immunity to sunlight, he focuses his efforts on capturing and devouring her. The Demon Slayer Corps exploits his obsession and set a trap which kills his remaining subordinates. Muzan kills Tamayo and numerous Demon Slayers before realizing that he was drugged with a variation of the humanity-restoring serum, with added poisons that nullifies most of his abilities, weakening him enough so that the Corps can fight him till dawn. Muzan's final act is to turn Tanjiro into a new demon so he would kill the Demon Slayers, but this fails when Tanjiro's friends help to restore his humanity.
Twelve Kizuki
The Twelve Kizuki (十二鬼月, Jūnikizuki) is a special group of demons who serve Muzan and have a special mark of their membership engraved on their eyes. Second only to Muzan, they are the most powerful demons to have lived. The six weakest are known as the Lower Ranks and have a single eye engraved, while the six strongest are called the Upper Ranks and have both eyes engraved. After Rui's death, Muzan decides to eliminate the Lower Ranks and have only the Upper Ranks under his command.
Upper Ranks
The Upper Ranks (上弦, Jōgen) are the high-ranking members of the Twelve Kizuki, with some having mutated their bodies to the point that, unlike other demons. they cannot be killed via decapitation. Their ranks were unaltered for over a century and no Demon Slayer had managed to kill any of them prior to Tanjiro and his friends joining the organization.
- Kokushibo (黒死牟, Kokushibō)
- Voiced by: Ryōtarō Okiayu[34] (Japanese); Jonah Scott[35] (English)
- Muzan's most powerful subordinate, who holds the title of Upper Rank One. As a human, he was a Demon Slayer named Michikatsu Tsugikuni (継国 巌勝, Tsugikuni Michikatsu) and the older twin brother of Yoriichi. Envious of his brother's talent, he became a demon to perfect himself as a swordsman without the fear of death. As a transformed Demon Slayer, Kokushibo uses a breathing style known as "Moon Breathing" (月の呼吸, Tsuki no kokyū), which is derived from Yoriichi's Sun Breathing. He dies while fighting Muichiro, Genya, Sanemi, and Gyomei, with Muichiro and Genya dying from their wounds soon after.
- Doma (童磨, Dōma)
- Voiced by: Mamoru Miyano[36] (Japanese); Stephen Fu[37] (English)
- A nihilistic demon who holds the position of Upper Rank Two. As a human, Doma was born with unusual rainbow eyes and pale-colored hair, which caused his parents to see him as perfect and blessed, and start a religious cult centered around him. After they died, he assumed control of the cult, and, after Muzan transformed him into a demon, began eating his followers under the belief that they would live forever inside him. One member of his cult was Inosuke's mother Kotoha, whom he devoured when she attempted to flee upon learning his true nature. He was also responsible for killing Shinobu's older sister Kanae. In a desperate measure to defeat him, Shinobu administers a massive dose of wisteria in her body and allows herself to be consumed, weakening him and allowing Kanao and Inosuke to kill him.
- Akaza (猗窩座)
- Voiced by: Akira Ishida[38] (Japanese); Lucien Dodge (English)
- A contentious demon who holds the position of Upper Rank Three. He despises those he considers weak and offers those he considers strong enough to earn his respect the opportunity to become demons. As a human, he was a teenager named Hakuji (狛治) who, as a child, stole to care for his ailing father before he committed suicide to free him from the burden of caring for him. Hakuji was adopted by a martial artist, Keizo, and trained under him while falling in love with his daughter Koyuki. Hakuji's adoptive family was killed when a rival dojo poisoned them, leading him to slaughter them single-handedly, after which Muzan turned him into a demon. Akaza battles and kills Kyojuro, and later battles Tanjiro and Giyu in the Infinity Castle, during which he regains his human memories and commits suicide by destroying his body and ceasing his regeneration, dying of his wounds.
- Hantengu (半天狗)
- Voiced by: Toshio Furukawa (original)[34] Yūichirō Umehara (Sekido),[39] Kaito Ishikawa (Karaku),[39] Shunsuke Takeuchi (Urogi),[39] Soma Saito (Aizetsu),[39] Koichi Yamadera (Zohakuten)[40] (Japanese); Christopher Corey Smith (original)[41] Yong Yea (Sekido), Caleb Yen (Karaku), Chris Hackney (Urogi), Brian Timothy Anderson (Aizetsu), Ben Balmaceda (Zohakuten) (English)
- A cowardly demon who holds the position of Upper Rank Four. Hantengu shows his true strength upon dividing himself into multiple clones which denote different emotions, each one possessing a unique appearance, personality, and ability: Sekido (anger), Karaku (pleasure), Aizetsu (sadness), Urogi (joy), Zohakuten (hatred), and Urami (resentment). As a human, he was a prolific criminal who boasted of his innocence despite his conviction before Muzan turned him into a demon. He attacks the Swordsmith Village with Gyokko, where Tanjiro, Nezuko, Genya, and Mitsuri confront him. Tanjiro kills him, but he lives long enough to inform Muzan of Nezuko's newfound immunity to sunlight.
- Nakime (鳴女)
- Voiced by: Marina Inoue[42] (Japanese); Amber Lee Connors (English)
- A biwa-playing demon who owns the Infinity Castle (異空間無限城, Ikūkan Mugen-jō), an alternate dimensional space that Muzan made his base of operations. As a human, she was a struggling musician who developed a habit of murdering prior to her performances, as she associated killing with applause. She ended up meeting Muzan when she tried to kill him, only to earn his respect for tracking him and granting her new life as a demon. Nakime becomes the new Upper Rank Four after Hantengu's death and later confronts Mitsuri and Obanai until Yushiro restrains her, prompting Muzan to kill her to prevent his enemies from taking control of the castle.
- Gyokko (玉壼)
- Voiced by: Kohsuke Toriumi[34] (Japanese); Brent Mukai[43] (English)
- An arrogant demon holds the position of Upper Rank Five. Unlike the others, Gyokko has a highly distorted djinn-like anatomy with his eyes being on his forehead and mouth along with two mouths being where his eyes would be. As a human, he was an ostracized villager who developed an obsession with corpses after his parents drowned at sea and their bodies washed up on shore. He kidnapped and killed a child before being stabbed and left for dead, after which Muzan transformed him into a demon. He claims himself to be an artist and takes pride in his creations, including twisting his victims' bodies into grotesque, living sculptures. He attacks the Swordsmith Village alongside Hantengu but is killed by Muichiro.
- Daki (堕姫)
- Voiced by: Miyuki Sawashiro[44] (Japanese); Erica Lindbeck[45] (English)
- A petulant demon who shares the position of Upper Rank Six with her older brother Gyutaro. Daki takes advantage of her work as an oiran in the red-light district to attract victims. As a human, she was named Ume (梅, lit. syphilis), after the disease that killed her mother, and was raised by Gyutaro in the red-light district slums they were born in. Her beauty led to success in the district at a young age despite her volatile personality, until she was burned alive at the age of thirteen by a customer she attacked. She was on the verge of dying alongside Gyutaro when Doma—who was the Upper Rank Six demon at the time—saved them by transforming them into demons, and later introduced them to the Twelve Kizuki. She wields an obi belt made of her flesh, which she also uses to absorb her victims and place them in a secret location before devouring them. After Zenitsu and Inosuke kill her, she returns to her former human appearance and meets Gyutaro in the afterlife, refusing to leave his side despite him trying to push her away so she would not have to go to Hell, reminding him of their promise to survive anything together.
- Gyutaro (妓夫太郎, Gyūtarō)
- Voiced by: Ryōta Ōsaka[46] (Japanese); Brandon McInnis[47] (English)
- A misanthropic demon who shares the position of Upper Rank Six with his younger sister Daki. As a human, he was born in the red-light district slums alongside Daki and was ostracized for his unsightly appearance. Ume gave him joy and allowed him to embrace his vile disposition while making a living as a debt collector, only to be mortally wounded after killing the customer who burned her alive; Doma later turned him into a demon. He usually hides within Daki's body and emerges whenever her life is threatened. He fights using his poisonous blood and two flesh sickles as his Blood Demon Art. As dual holders of Upper Rank Six, Gyutaro must be decapitated together with Daki to be truly killed. After Tengen and Tanjiro kill him, he expresses regret over being a negative influence to Ume when she was alive and decides to go to Hell alone to atone for their sins, but he relents after Ume refuses to leave his side.
- Kaigaku (獪岳)
- Voiced by: Yoshimasa Hosoya (Japanese); Alejandro Saab[48] (English)
- A young demon who attained the position of Upper Rank Six following Daki and Gyutaro's deaths. As a human, he was one of the orphans under Gyomei's care; he was chased out by the other children for stealing the temple's money and encountered a demon, which he let into the temple in exchange for having his life spared, leading to their deaths and Gyomei's wrongful imprisonment. He then became a member of the Demon Slayer Corps, learning the Thunder Breathing from Jigoro along with Zenitsu, before betraying them and allowing Kokushibo to transform him into a demon, leading Jigoro to commit seppuku in atonement. Unlike Zenitsu, who only mastered the first of the six forms of Thunder Breathing, Kaigaku only mastered the other five. He is killed when Zenitsu strikes him with a self-taught, seventh form.
Lower Ranks
The Lower Ranks (下弦, Kagen) of the Twelve Kizuki, whose membership is constantly shifting compared to the Upper Ranks. Following Rui's death, Muzan kills all of them except for Emmu for being worthless to his plans.
- Enmu (魘夢)
- Voiced by: Daisuke Hirakawa[49] (Japanese); Landon McDonald[49] (English)
- A sadistic demon who holds the position of Lower Rank One and is the main antagonist of the Mugen Train arc. He is intensely devoted to Muzan, having rose up to his current status to be acknowledged by him. As a human, he was a delusional sociopath who pretended to be a healer to swindle people out of their money and was transformed into a demon by Muzan, who originally intended to eat him. His Blood Demon Art allows him to manipulate a person's dreams and nightmares. Being the only Lower Rank that Muzan spared after he slaughtered the others, Enmu is tasked with killing the Hashira and Tanjiro and lays a trap for Tanjiro and his friends on a train that he later fuses himself to, but Tanjiro ultimately kills him.
- Rui (累)
- Voiced by: Kōki Uchiyama (Japanese); Billy Kametz[50] (English)
- A child-like demon who holds the position of Lower Rank Five. As a human, he was a sickly young boy who was transformed by Muzan. He killed his parents in self-defense when they attempted to kill him out of atonement; the ordeal caused Rui to forget his human memories. Being a favoured member of the Twelve Kizuki, he gains Muzan's permission to transform other humans and demons with his blood into a replacement family, who he abuses due to his warped view of familial bonds. This causes him to be envious of the Kamado siblings' bond, as he loses his calm demeanour and attacks erratically until Giyu kills him. In his final moments, he remembers his parents and reunites with them in Hell.
- Kyogai (響凱, Kyōgai)
- Voiced by: Junichi Suwabe[51] (Japanese); Steve Blum[52] (English)
- A demon and former Lower Rank Six of the Twelve Kizuki. He is known as the "Drum Demon" (鼓鬼, Tsuzumi Oni). After Muzan strips him of his rank due to slowly losing the ability to eat humans and reaching his limit, he obsessively tries to earn his spot back in the Twelve Kizuki, attacking and eating humans who pass by the Tsuzumi Mansion. He fights using the tsuzumi drums embedded into his body; striking them can change the house's rooms around as well as his position in it, and also allows him to unleash powerful air slashes. Following a lengthy battle, Tanjiro kills him.
- Kamanue (釜鵺)
- Voiced by: KENN (Japanese); Alan Lee[53] (English)
- A demon who holds the position of Lower Rank Six. He is the first member of the Lower Ranks that Muzan kills when he decides to purge the Lower Ranks after he questions his expectations, which Muzan sees as defiance.
- Mukago (零余子)
- Voiced by: Kana Ueda[54] (Japanese); Kira Buckland[54] (English)
- A demon who holds the position of Lower Rank Four. Muzan kills her after deducing that she was more afraid of the Demon Slayers than him and interpreted her attempt at saving face as contradicting him.
- Wakuraba (病葉)
- Voiced by: Sōichirō Hoshi[55] (Japanese); Stefan Martello[55] (English)
- A demon who holds the position of Lower Rank Three. Muzan kills him when he tries to escape the Infinity Castle.
- Rokuro (轆轤)
- Voiced by: Taiten Kusunoki[56] (Japanese); Ray Chase[56] (English)
- A demon who holds the position of Lower Rank Two. He is killed when he asks Muzan for his blood to gain strength and fight for him, which Muzan saw as undermining his authority.
Spider Family
- Spider Demon (Mother) (蜘蛛鬼「母」, Kumo Oni: Haha)
- Voiced by: Ami Koshimizu (Japanese); Allegra Clark (English)[50]
- A member of the Spider Family. As a human, she was a young girl who was turned into a demon, with Rui later forcing her to assume the role of "Mother" and have her appearance altered. She can control her victims like puppets using her silk threads, which are attached to them by small white spiders. She has also somehow come into possession of the headless corpse of a demon with scythes for hands, which due to its lack of a head is invincible. She lives in fear of Rui, and ultimately allows Tanjiro to slay her when they fight, allowing her to be free.
- Spider Demon (Father) (蜘蛛鬼「父」, Kumo Oni: Chichi)
- Voiced by: Tetsu Inada (Japanese); Kellen Goff (English)[50]
- A member of the Spider Family, who assumes the role of "Father". Unlike the rest of his family, his appearance is less human, possessing a spider's head atop a humanoid body. When he attacks Tanjiro and Inosuke, he is killed after Giyu intervenes.
- Spider Demon (Brother) (蜘蛛鬼「兄」, Kumo Oni: Ani)
- Voiced by: Showtaro Morikubo (Japanese); Derek Stephen Prince (English)[50]
- A member of the Spider Family, who assumes the role of "Elder Brother" and is one of the two in the family that does not look human, possessing a human head and a spider's body. He has the ability to turn humans into monstrous semi-spiders when his minions bite them. He is ultimately killed by Zenitsu.
- Spider Demon (Sister) (蜘蛛鬼「姉」, Kumo Oni: Ane)
- Voiced by: Ryōko Shiraishi (Japanese); Erica Lindbeck (English)[50]
- A member of the Spider Family, who assumed the role of "Elder Sister" after begging Rui for safety from the Demon Slayers. She has the ability to create acidic cocoons of thread that dissolve her victims and convert them into food. She nearly kills Murata, but Shinobu subdues and kills her.
Other Demons
- Temple Demon (お堂の鬼, Odō no Oni)
- Voiced by: Hikaru Midorikawa[8] (Japanese); Ben Diskin[57] (English)
- A demon who Tanjiro and Nezuko briefly encounter and defeat together.
- Hand Demon (手鬼, Te Oni)
- Voiced by: Takehito Koyasu, Aki Toyosaki[58] (child) (Japanese); Kirk Thornton,[59] Jessica DiCicco[60] (child) (English)
- A vengeful demon who Sakonji captured and trapped on a mountain and was used for testing applicants for the Demon Slayer Corps. Unable to escape the mountain, he made it his goal to target and eat Sakonji's disciples as revenge, with only Giyu and Tanjiro, the one who would eventually kill him, surviving.
- Swamp Demon (沼鬼, Numa Oni)
- Voiced by: Ryōhei Kimura[32] (Japanese); Sean Chiplock[33] (English)
- A demon responsible for the disappearance of several girls, who he prefers to be under the age of 16 or else they would "become rotten". He is the target of Tanjiro's first assignment as a Demon Slayer, and is killed by him.
- Yahaba (矢琶羽)
- Voiced by: Jun Fukuyama[32] (Japanese); Xander Mobus[33] (English)
- A demon who serves Muzan and falsely believes that he is one of the Twelve Kizuki. He has the ability to manipulate the movement and direction of midair objects using the eyeballs on his palms to control telekinetic arrows. He is killed by Tanjiro.
- Susamaru (朱紗丸)
- Voiced by: Mikako Komatsu[32] (Japanese); Sarah Ann Williams[33] (English)
- A demon who serves Muzan and falsely believes that she is one of the Twelve Kizuki. She has the ability to sprout multiple arms and create special Temari, using them as projectile weapons in conjunction with Yahaba's ability. She is defeated when Tamayo uses her hypnosis to trick her into triggering Muzan's curse, causing her body to destroy itself.
- Tongue Demon (舌鬼, Shita Oni)
- Voiced by: Tarusuke Shingaki[32]
- A demon that lived in the Tsuzumi Mansion until Zenitsu kills him. He has four eyes and a gigantic prehensile tongue that functions as a bladed weapon.
- Horned Demon (角状鬼, Tsunojō Oni)
- Voiced by: Yoshihisa Kawahara
- A demon that lived in the Tsuzumi Mansion until Inosuke kills him. He is massively obese and seems unaware of the presence of the other two demons.
- Slasher (切きり裂さき, Kirisaki)
- Voiced by: Kentarō Itō
- The nickname given to a sadistic and cruel demon that appeared during the investigation of the Mugen Train and was responsible for attacking humans until Kyojuro killed him. He is exclusive to the anime, only appearing in Episode 27.