The Spider Demon (Girl) (蜘く蛛も鬼おに「姉あね」 Kumo oni: Donkey?) was part of the spider family.

Spider Demon (girl) | Demon Slayer Kimetsu No Yaiba


The Spider Demon’s Daughter shares many physical traits with her “younger brother”, Rui. She has the appearance of a demon girl in her early teens, with a milky-white complexion, snow-white hair, and pure-white eyes separated from her silver pupils. Her face is adorned with red dot patterns, similar to those of her “family”.

Originally, her appearance as a demon was totally different from the one she has today. She was transformed and her features altered at Rui’s request in order to be accepted into his family. Her hair was black, her eyes were slitted like a cat’s, and her skin was pale gray.


The Daughter of the Spider Demon is the most cautious member of her “family”. Rather than jump straight into battles with demon slayers, she prefers to observe and stand back. She is also very cowardly, both when confronting the Demon Slayer Corps and when dealing with her family’s internal conflicts. When her “mother” is mistreated and reprimanded by her “younger brother” and “father”, she stands back and gives him a stern look, showing her weakness rather than coming to his aid. She again reveals her cowardice by trying to convince Rui to run away rather than fight after the defeat of most of their family, which angers him and hurts her.

In reality, the Daughter of the Spider Demon hates her “family” and thinks she would probably have been better off on her own. She considers the other members of her family fools for playing along with Rui, although she feels no real emotional attachment to them. However, she did whatever it took to survive and stayed with them, knowing that she had no chance of getting out if she tried to escape. She even tried to attract the sympathy of Shinobu Kocho, a demon slayer, by claiming to have been forced to act this way by Rui. However, her actions contradict her words, as she has done her utmost to stay with Rui and his family, showing that she is only doing what is practical for her own survival. Later, she falls for Shinobu’s false sympathy and openly confesses the total number of her human victims.


Originally, the Spider Demon Daughter was a lonely young demon girl who decided to join Rui’s group on Natagumo Mountain to survive, out of fear of the demon killers. Rui forced her new “family” to abandon their former appearances to resemble her own. The Spider Demon’s Daughter was forced to become his “Big Sister” and protect him at the cost of her own life, as he believed that the elder should always protect the younger. She and her family then began attacking the human inhabitants of the mountain, attracting the attention of the Demon Killer Corps, who sent a large number of killers to eliminate the demons.

The Daughter of the Spider Demon herself managed to kill at least 80 humans during her stay on the mountain. She stored them in her thread bags, using her Blood Demon Art to feed on them later. These thread bags were discovered by Shinobu when she arrived on the mountain with Giyu Tomioka to help the killers.

Spider Demon (girl) | Demon Slayer Kimetsu No Yaiba


Mount Natagumo Arch

In her first appearance, the Spider Demon Girl is spotted by Tanjiro Kamado and Inosuke Hashibira shortly after the death of the Spider Demon (Mother). She calls for help from the Spider Demon (Father) and flees, leaving him to fight the two demon-slayers alone. Later, she is confronted by Rui; he attacks her with his own sons, inflicting wounds on her face. As she suffers, Tanjiro steps in to save her.

The Spider Demon Girl observes the fight between Tanjiro, Nezuko and Rui, but doesn’t get directly involved. When Rui expresses his wish to make Nezuko his sister, the Girl begs him not to abandon her, but he beheads her instead, reproaching her for not fulfilling her role as big sister. He then gives her one last chance to kill everyone else on the mountain, promising to forget a “certain incident”. She picks up her own head and leaves.

As she flees, healed of her wounds, the Spider Demon’s Daughter recalls how she and the other members of the Spider Demon family joined Rui in the hope of protection, but ended up being mistreated, punished and even executed by Rui if they failed. She realizes she’s not as naive as the other demons and remembers the exact reasons why Rui hurt her before: having suggested she flee from the demon slayers and accidentally reverting to her original appearance.

The Girl meets Murata, a demon killer, and traps him in a cocoon of acid using her Blood Demon Art. She explains how the acid first dissolves the clothes inside the thread bags, then melts the rest of his body…

Suddenly, Shinobu appears behind the Spider Demon Girl, wishing her a good evening and commenting on the beauty of the moon. Surprised, the Demon Girl attacks him with her sons, but Shinobu easily dodges them. Drawing her sword, Shinobu notices that the Demon is unwilling to cooperate with her.

The Spider Demon Girl implores Shinobu to let her live, explaining that she would be killed if she disobeyed Rui. Shinobu, sympathetic to her desperation, offers to cooperate if she answers a few questions. The first question concerns the number of people she has killed. The Demon answers five, but Shinobu assures her that she doesn’t need to lie. She corrects her answer, saying she has killed eighty humans.

Despite the Demon’s denials, Shinobu reveals that they both come from the same side of the mountain and that she found forty Demon cocoons on that side. Shinobu clarifies that she’s not angry, but simply wants accurate information. When asked why she’s checking this information, Shinobu explains that in order to become friends and pay tribute to those who have died, the Spider Demon Girl will have to be punished. She describes with horror what she has in mind, adding that she won’t die, so there will be no after-effects.

Enraged, the Demon attacks Shinobu again, but she easily avoids it with her Insect Dance, Butterfly Caprice. Shinobu laments the Demon’s poor choice, then watches him collapse. She explains that although she can’t decapitate the Demon, her sword is impregnated with poison, a powerful weapon against Demons. Shinobu then introduces herself as Insect Hashira of the Demon Slayer Corps. She then apologizes, realizing that the Spider Demon Girl is already dead and hasn’t heard her explanation.

During these events, Spider Demon Girl realizes that Shinobu’s Butterfly Dance did not decapitate her. However, she begins to bleed from several places on her body. Finally, she lies dead on the ground, her body twisted in pain and covered in wounds.

Spider Demon (girl) | Demon Slayer Kimetsu No Yaiba


Supernatural abilities

Shape-shifting: The Spider Demon Girl possesses the ability to shape-shift to alter her physical appearance to match Rui’s. However, in the event of fear or surprise, she automatically reverts to her original appearance, demonstrating that she must make a conscious effort to maintain her new appearance.

Art of the blood demon

Spider physiology: Like the other members of her “family”, the Spider Demon Girl possesses spider-like characteristics and abilities.

  • Silk manipulation: She can manipulate threads made from her own cells. Her silk is extremely strong, stronger than metal, and not even a Nichirin blade can cut or pierce it.
  • Acid manipulation: She can generate and manipulate acid from her own blood and flesh. This acid can easily dissolve human beings, although the process is a little slow.

Fighting style


Acid cocoon (溶よう解かいの繭まゆ Yōkai no mayu?): This technique involves trapping the target in a cocoon of acid-filled threads capable of dissolving clothing, then attacking the victim’s flesh, rendering it soft and ready to be consumed.

Spider Demon (girl) | Demon Slayer Kimetsu No Yaiba


Mountain Natagumo Arch

  • Shinobu Kocho vs Spider Demon (Girl)


  • In the anime, additions that were not in the manga were made to the Spider Demon Girl story. In the manga, there were more than five members of the spider family, although it is implied that they were killed before the arc. These additions include:
  • An explanation of how she joined the family and how the members were treated by Rui and each other.
  • A more detailed exposition of the other members of the spider demon family.
  • His interactions with another “big sister spider demon” who proposes running away together in Rui’s absence. Eventually, the Spider Demon Girl betrays her to gain Rui’s favor, resulting in the death of the other big sister.
  • In the manga, all four members join Rui before meeting the elder sister, whereas in the anime, they join Rui after the elder sister.

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