Unveiling Kidomaru: The Assassin Demon of Kyoto
Japanese folklore is a tapestry woven with threads of heroism, tragedy, and the supernatural. Among the myriad creatures that populate these tales—collectively known as Yokai—few archetypes are as feared as the Oni (ogres or demons). While many Oni are depicted as brutes wielding iron clubs, Kidomaru (鬼童丸) stands out as a figure of cunning, stealth, and vengeance. Known primarily as a villain who sought to assassinate the legendary hero Minamoto no Yorimitsu, Kidomaru’s story is a fascinating dive into the darker side of Kyoto’s history.
Origins of the Demon Child
The name Kidomaru translates roughly to “Demon Child” or “Ogre Child.” His lineage varies depending on the text, but the most prevalent tradition identifies him as the son of Shuten-doji, the infamous King of the Oni who terrorized Mt. Oeyama.
According to folklore, after the hero Minamoto no Yorimitsu (also known as Raiko) slew Shuten-doji, the surviving Oni women were dispersed. Kidomaru was either born shortly before this event or was a child left behind. Some legends suggest he was abandoned near a temple, possibly Mt. Hiei, where he was taken in by monks. However, his demonic nature could not be suppressed. He was eventually expelled for his wicked behavior, retreating into the mountains to embrace his heritage and plot revenge against the man who killed his father.
The Legend: Ambush at Ichihara Moor
The most famous tale involving Kidomaru is the Ambush at Ichihara Moor. Unlike the brute force typical of other Oni, Kidomaru employed deception and guerrilla tactics, marking him as a sorcerer-assassin figure.
Having learned that Minamoto no Yorimitsu would be visiting his brother in the northern outskirts of Kyoto, Kidomaru laid a trap. He traveled to the Ichihara Moor, an area known for high grass and desolation. To remain undetected, killed a free-roaming ox, skinned it, and hid inside the raw hide, lying in wait by the roadside like a discarded carcass.
However, Yorimitsu was no ordinary warrior; he was renowned for his intuition and martial prowess. As Yorimitsu and his retainers (the famous Four Heavenly Kings) passed the dead ox, Yorimitsu sensed a palpable killing intent (known as sakki). Suspecting a trap, he ordered his retainer, Watanabe no Tsuna, to shoot an arrow at the ox.
The arrow struck true. Realizing his cover was blown, Kidomaru burst forth from the ox hide, sword in hand, attempting to slash at the hero. A fierce battle ensued, but despite the demon’s ferocity and dark magic, he was no match for the legendary demon-slayer. Yorimitsu cut Kidomaru down with a single stroke, ending the lineage of the Oeyama demons.
Kidomaru in Modern Culture
While Kidomaru is a centuries-old figure, his legacy thrives in modern Japanese pop culture, often reimagined for new audiences.
Anime and Manga
Perhaps the most globally recognized iteration of Kidomaru appears in the anime and manga series Naruto. Here, he is depicted as a member of the “Sound Four,” a squad of elite bodyguards. While the anime version takes creative liberties—giving him spider-like abilities and six arms—it retains the core concept of a tactical fighter who analyzes his opponents, mirroring the mythological figure’s cunning nature.
Video Games
In the realm of gaming, Kidomaru appears in titles like Nioh 2 and the Shin Megami Tensei / Persona series. These depictions often lean closer to the traditional Ukiyo-e woodblock prints, showcasing him as a wild-haired, fierce warrior, sometimes clad in the iconic ox skin.
Ukiyo-e Art
The battle at Ichihara Moor was a favorite subject for Edo-period woodblock artists. Masters like Utagawa Kuniyoshi produced dynamic prints of Kidomaru bursting from the ox hide. These prints are highly collectible and have defined the visual image of the character for generations.
Traveler’s Tips: Tracing the Oni
For travelers interested in Japanese mythology, Kyoto offers several sites to connect with the legend of Kidomaru.
- Kumogahata & Ichihara (Northern Kyoto): The actual site of the legendary ambush is located in the Sakyo Ward. While it is now a quiet residential and semi-rural area, visiting the moodier, forested outskirts can give you a sense of the isolation that once made it a perfect spot for an ambush.
- Seimei Shrine: While dedicated to the Onmyoji Abe no Seimei, this shrine often holds information and lore regarding the spiritual battles of the Heian period, including those involving Yorimitsu and Oni.
- Kyoto International Manga Museum: To see how folklore transforms into pop culture, this museum is a must-visit. You can often find archived copies of manga featuring Yokai inspired by Kidomaru.
Sources & Further Reading
To deepen your understanding of Kidomaru and the world of Japanese demons, consider exploring the following texts and collections:
- The Kokon Chomonju (Notable Tales Old and New): A Kamakura-period collection of setsuwa (anecdotes) that catalogs various supernatural encounters.
- Otogizoshi: A collection of medieval short stories where many tales of Minamoto no Yorimitsu and the slaying of Oni are detailed.
- Toriyama Sekien’s Gazu Hyakki Yagyo: The classic illustrated encyclopedia of Yokai, which provides the visual foundation for many supernatural creatures in Japan.
- Works of Utagawa Kuniyoshi: Specifically his warrior prints (Musha-e), which vividly depict the confrontation between Kidomaru and Raiko.