Meet the powerful yokai that inspired the demon king in ‘Demon Slayer’

Demon Slayer: Kimetsu no Yaiba, a Japanese manga series first published in 2016, has quickly become one of the most successful media franchises to date. The story follows teenage Tanjiro Kamado, who becomes a demon slayer after his family is slaughtered and his younger sister Nezuko is turned into a demon.

Throughout the series, Tanjiro and his companions encounter a variety of monsters, many of which resemble demons, or oni, from Japanese folklore. At the center of them all is Muzan Kibutsuji, the enigmatic demon king who mirrors the power, influence, deception, and shapeshifting abilities of Nurarihyon, a legendary yokai (supernatural creature).

“[Yokai] generally occupy a spiritual zone somewhere between kami (Shintō gods or spirits) and oni,” says John Pavel Kehlen, professor of Asian literature at Soka University of America. “They reside neither in heaven nor in hell but live in the human world because they have some lingering attachment, whether anger, romantic obsession, craving, or the desire to fool people.”

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While Nurarihyon’s origins are murky, it has influenced manga and anime into the 21st century. Featured in shows such as GeGeGe no Kitarō, Nura: Rise of the Yokai Clan, and Hozuki’s Coolheadedness, the quasi-demon also played an essential role in graphic novels such as Nurarihyon no Mago and The Haunted Bookstore: Gateway to a Parallel Universe. 

From inspiring characters and themes to shaping visual aesthetics and cultural context, here’s how this ancient creature continues to captivate audiences.

Unclear origins

Images of Nurarihyon, commonly depicted as an elderly figure with a prominent, rounded head, first emerged during Japan’s Edo period in Sawaki Sūshi’s Hyakkai Zukan and Toriyama Sekien’s Gazu Hyakki Yagyō (The Illustrated Night Parade of a Hundred Demons).

According to Michael Dylan Foster, a professor of East Asian languages and cultures at the University of California, Davis, and author of The Book of Yokai: Mysterious Creatures of Japanese Folklore, Nurarihyon is typically portrayed in folklore as a benign yokai who sneaks into homes to enjoy tea or other comforts while the occupants are away. 

But over time, it developed a reputation for being cunning and sly, using its shape-shifting and manipulation skills to outsmart humans or other yokai. Zack Davisson, a writer and Japanese folklorist, says the shift in personality could stem from Koshoku Haidokusen’s tale about a married man who falls in love with a prostitute. In the story, Nurarihyon is introduced as a “faceless, catfish-type creature who is the spirit of deception.” 

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This narrative sparked theories proposing a correlation with the legendary spherical sea creatures in the Seto Inland Sea in Okayama Prefecture, commonly called umi bozu. These bulbs, about the size of a human’s head, tease and elude fishermen, submerging just out of reach before resurfacing mockingly, says Foster, which could allude to Nurarihyon’s enigmatic nature. 

Davisson adds that Mizuki Shigeru’s depiction of Nurarihyon in the anime GeGeGe no Kitarō played a crucial role in creating the yokai we see in modern-day pop culture. In the show, Nurarihyon is the supreme commander of all supernatural beings and the leader of the yokai night parade.

According to Foster, folklorist Fujisawa Morihiko labeled an image of Nurarihyon in his book with the caption “yōkai no oyadama,” which could be translated as “leader of yokai,” “yokai boss,” or “yokai chief.” 

Foster says the way Nurarihyon has stayed relevant in the modern-day may be due to the unique nature of the yokai. 

“Perhaps it is the folkloric indeterminacy of the Nurarihyon—the fact that he is an interesting-looking figure but has no clear characteristics—that has allowed him to become a sort of mutable figure that can be developed in various ways in popular cultural materials,” he says.