- For the Hongo Wonder, see Kusa-Kamaitachi.
Despite his name, the Kamaitachi from Yōkai Castle does not resemble the weasel yōkai of legend. However, there is also a more accurate Kamaitachi called Kusa-Kamaitachi, who appears in Saishinban GeGeGe no Kitarō.
Shigeru Mizuki's design of Kamaitachi is different from the weasel yōkai of legend. He's a short man with a short haircut and an elongated mouth, similar to an anteater's snout. He's often depicted wearing a robe.
In the 2007 anime, he wears a light green kimono and a black haori. His hair is blond and is slicked back. His skin is pink, and his ears are slightly pointed.
In the 2018 anime, Kamaitachi has light purple skin, with pointy ears, short orange hair, and several scratch marks across his face. He wears a dark brown, full-body robe, that reaches to his feet and hands. After being resurrected by Nanashi, a dark inverted pentagram appears on his forehead.
In the 2007 anime, Kamaitachi tends to act self-centered and egotistical. He initially refuses to help Kyūso free Nurarihyon, as he finds the job too boring for him. He is a fan of shōjo manga, where he changes his mind when he's promised a rare shōjo manga in return. He values his pride, and becomes enraged when he's been deceived or humiliated by others. His sickle arms are focused on more in this adaptation, and he's depicted as being powerful enough to regularly fight evenly with Kitarō.
Shonen Magazine/1968 Anime
Kamaitachi works with Tantanbō and Futakuchi-Onna at Yōkai Castle, kidnapping children to convert them into yōkai. He was defeated along with Tantanbō when Kitarō forced Nezumi-Otoko to place a rope seal around the castle, turning it and everyone inside into stone. He appears in the third episode of the 1st anime adaption, Yōkai Castle.
In Yōkai Mannen-Dake he reappears as an ally. He chops down several yōkai bamboos with his sickle arms, but when confronting Mannen-Dake's true body his sickles break. Afterward, he takes part in the final battle against Mannen-Dake.
Kamaitachi is unsealed as a stone shrine is knocked over during construction, where he and the others cause havoc by making the construction machinery go haywire. He abducts a little girl actress during filming, taking her to the Yōkai Castle. After the Yōkai Castle rises from the ground, he flies above the crowd of humans to instill fear into them and returns to the castle. Inside he scolds Nezumi-Otoko, as they do not take orders from him. After Tantanbō orders the rat Yōkai to kidnap children, he explains that they are going to turn them into Yōkai. He and the others soon hear the clip-clop of Kitarō. After hearing a crash in the room of the kidnapped children, he inspects it and finds that they tried to escape through the ceiling. He takes them to Tantanbō and asks what they should do with them laughing as the giant head Yōkai turns them into stone and shrinks them. Nezumi-Otoko arrives warning that Kitarō has entered the castle, where Kamaitachi is not afraid at all about it. He decides to go check on Futakuchi-Onna, who may have eaten the Yōkai boy by now. He arrives just after the two-mouthed woman falls to her death, slicing through the wooden beams of the floor and attacks Kitarō and Sunakake-Babaa. He chases after them through the stairs, surprising them through a hole and lands on a beam. He gloats over their failure but is caught by Ittan-Momen, who keeps him restrained as Sunakake-Babaa asks how to make the castle sink into the ground once more. He claims that he does not know, but Ittan-Momen tightens his hold to make him confess. Eventually, he tells the cloth Yōkai, complaining as he and the castle sink into the ground. In addition to reappearing in episode #74 Yōkai Mannen-Dake episode, he also takes part in the battle against Qi (Movie 3), but is subdued and transformed into a Yōkai Cloth. In this anime he has green skin, orange hair and wears a brown robe.
He appears in both episode #66 and #67 of the fourth anime adaption, Ominous Clouds! Yōkai Castle (Part 1) and Ominous Clouds! Yōkai Castle (Part 2). This adaption introduces his sickle arm ability to the anime franchise. This time, his skin is yellow, his hair is brown and his robe is white.
In the fifth anime, he first appears in episode #39, Nurarihyon's Last Day as a freelance assassin. In an attempt to save Nurarihyon from being imprisoned, Kyūso tries to hire him. Kamaitachi refuses the job, stating that he finds it too boring. Kyūso leaves disappointed, but later returns with Nezumi-Otoko. Once again, Kamaitachi turns them down, but not before Nezumi-Otoko slips a shōjo manga onto his desk. Kamaitachi quickly asks him where he found it, and it's revealed that the manga was written by one of his favorite authors, Mao-Sensei. Nezumi-Otoko bribes him into helping with Nurarihyon's jailbreak by offering him a shōjo manga called "Otome-zaka Korori", the debut work of Mao-Sensei. Kamaitachi accepts the job.
In the Hida Mountains, Nurarihyon, along with Shu-no-Bon and Jakotsu-Babaa are being transported by the Tengu Police to be imprisoned. Kamaitachi suddenly swoops in, taking down six Tengu officers at once. He begins fighting with Kuro-Karasu, giving time for Nurarihyon to formulate a plan to escape. At his request, Nezumi-Otoko throws the copy of "Otome-zaka Korori" to him. To his shock, he finds that it's simply a collection of crude drawings by the rat yōkai. Enraged, Kamaitachi tries to kill him with a powerful tornado attack, but is thwarted and defeated by Kitarō. Angry at Kitarō for wounding his pride, he decides to join Nurarihyon's faction to eventually get revenge. 
He makes his story appearance in episode #61, Tantanbō of the Yōkai Castle.
He appears in the third episode of the sixth anime adaption, Tantanbō's Yōkai Castle. In this episode, he awakens along with Tantanbō and Futakuchi-Onna. After the trio saw that humans have polluted, twisted, and wounded the world as they pleased, they believed the world did not need humans. They kidnapped 13 children, one of which was Mana, to resurrect the Yōkai Castle and create a world only of Yōkai. He was defeated when Konaki-Jijii in his stone form was catapulted into him by Sunakake-Babaa and Ittan-Momen.
Some months later, Kamaitachi and the others were revived by Nanashi, forming an Obake School where children could come and become ghosts. During one night, he teaches a class of middle school students about math through jars filled with blood and liver, asking Sōma to answer a problem and supports him when he could not answer, encouraging him to do better. The next night Kamaitachi and the others gather the students outside, planning on using them as yōkai fodder. When some attempt to leave, he and Tantanbō stop them. He targets Hiroto sadistically gleeful about wanting to cut his mouth up to his ears, almost poking his eye out and wanting him to scream before Neko-Musume arrives and gets his attention. He joins in the battle against her and Kitarō, eventually being defeated by Neko-Musume.
Powers and Abilities
Kamaitachi has the ability to fly around and high speed, often creating whirlwinds that can cut flesh. Starting with the fourth anime, he gains the ability to transform his arms into sickles, making him closer to the Kamaitachi of legend.
Wind Breath: He can breathe out a powerful wind vortex from his mouth and he can reside within it.
Flight: Kamaitachi is able to fly in the air with incredible speed. He is capable of slicing through wooden beams as he flies.
The Kamaitachi is most common in the Kōshinetsu region. There are several conceptions of how it looked or operated, but the most common is one of a trio of weasels with sharp claws, riding on a gust of wind and cutting people's skin on the legs. According to this interpretation, the first weasel knocked the unsuspecting victim down, the second cut the victim's flesh, and the third applied medication to the wounds so that at the time the victim realized what was happening they were left only with painful wounds that weren't bleeding. Sometimes the three are described as brothers, sometimes as triplets. This account can be traced back to Toriyama Sekien, who was presumably also the first to imagine the apparition to have the form of a weasel.
The idea of lightning-fast weasels wielding razor-sharp claws appealed to manga and anime artists and the kamaitachi often appears in said media.
|Main||Nurarihyon (leader) • Shu-no-Bon • Jakotsu-Babaa|
|Monday Dramaland||Miage-Nyūdō • Nobiagari • Okkamuro • Amikiri • Vampire Elite|
|The Demon Flute||Sakurako • Yadōkai • Nupperabō • Kawazaru|
|1985 Anime||Chinpo • Guwagoze • Oboro-Guruma • Tsujigami • Raijū • Kowai • Oiteke-Bori • Grass Kamaitachi • Okuri-Chōchin • Ashi-Arai • Nururibō|
|1996 Anime||Momon-Jii • Backbeard • Kōmori-Neko • Grimalkin • Viy • Giant • Youaltepuztli • Ustrel • Poltergeist • Golem|
|2007 Anime||Kamaitachi • Kyūso • Kani-Bōzu • Dodomeki • Mashiro • Yōkai Castle|
|2008 film||Nure-Onna • Yasha • Satori • Te-no-Me • Gasha-Dokuro|
|2018 Anime||Neko-Sennin • Nuppeppō • Tsuchi-Korobi|