The kumiho (literally “nine-tailed fox”) is a creature that appears in the oral tales and legends of Korea. Unlike its Japanese and Chinese counterparts (the kitsune and the huli jing), that are sometimes considered benevolent creatures, the Korean kumiho is always depicted as evil. According to those tales, a fox that lives a thousand years turns into a kumiho. It can freely transform, among other things, into a beautiful girl often set out to seduce men. There are numerous tales in which the kumiho appears. Several of those can be found in the encyclopedic Compendium of Korean Oral Literature (한국 구비문학 대계).
The only role the kumiho—the nine-tailed fox—plays in Korea is the demoness. Whether she appears as maiden, wife, or succubus, the kumiho's sole goals are power and death. She is the only kind of fox that kills with her own hands, and also the only kind of fox that eats her prey.
Kumiho means, literally, “nine-tailed fox.” The following description appears (word for word) in both the Donga Color World Encyclopedia (Tonga wonsaek segye paekhwasajeon) and the Dusan Great World Encyclopedia (Tusan segye taebaekhwasajeon):
“A fox with nine tails that commonly appears in the oral tales of our country. It can freely transform into, among other things, a bewitching girl that seduces men. A fox that lives a thousand years is said to turn into a kumiho. There are a number of legendary tales in which the kumiho appears.” A half dozen or so of those legendary tales can be found in the encyclopedic Compendium of Korean Oral Literature (Hanguk kubimunhak taegye). A quick look at them will help supplement the brief description given above.
In “Transformation of the Kumiho” (“Kumihoui pyeonshin”), a kumiho transforms into an identical likeness of a bride at a wedding, and not even the bride's mother can tell them apart. The kumiho is finally discovered when her clothes are removed. In “Pak Munsu and the Kumiho” (“Pakmunsuwa kumiho”), the famous character Pak Munsu encounters a girl living alone in the woods who has a distinctly fox-like appearance. “The King and the Kumiho” (“Wanggwa kumiho”) tells of a king who meets a girl in the woods at night and tells her to take off her clothes after promising to save her debt-laden father. The tale records that it was too dark for the king to see whether she was actually a girl or a fox, indicating that if it had been light the difference would have been obvious. In “The Maiden who Discovered a Kumiho through a Chinese Poem” (“Hansiro kumihoreul aranaen ch'eonyeo”) we read that the kumiho was ultimately revealed when a hunting dog caught the scent of the fox and attacked. All of these details would seem to indicate that, while the kumiho may be able to change its appearance, there is still something fox-like about it; its countenance changes, but its nature does not.
The kumiho is typically pictured as taking a female form when transforming into a human being (as indicated in the encyclopedia entries), but the kumiho in “The Maiden who Discovered a Kumiho through a Chinese Poem” turns into a young man who attempts to trick the maiden into marrying him. It should be noted that this is the only case where the kumiho transforms into a man; in the rest of the tales the kumiho takes the form of a beautiful girl.
Although it is not indicated in the encyclopedia entry quoted above, the kumiho is not a benign trickster who delights only in fooling people. There is no doubt that the kumiho is an evil creature; unlike the fox of Japanese folklore, who will sometimes change into a woman to marry a man who has been kind to it, the kumiho never appears as a benevolent figure. The kumiho encountered by Pak Munsu intended to harm him, but he was able to escape. Likewise, the amorous king was saved by the timely arrival of a mountain spirit who struck the kumiho on the cheek and forced her to reveal her true form. Others were not so lucky. In “The Hunter and the Kumiho” (“P'osuwa kumiho”), a hunter comes upon a fox scratching at a human skull in the woods. Before his eyes, the fox changed into an old woman and went down into a nearby village (the scratching of the skull and the subsequent metamorphosis introduces an element of sympathetic magic into the kumiho's transformation, but there is not space enough here to flesh out this aspect). The hunter followed and saw her “reunited” with her children, who had puzzled over her absence of several months. The hunter was able to warn the children that their mother had been killed by the kumiho, and the kumiho intended them to be her next victims. “The Emperor's Kumiho Daughter-in-Law” tells of us a Chinese emperor's son who married a kumiho. After the marriage, the country's retainers mysteriously began to die one by one. The tale's hero eventually discovered the kumiho and was given permission by the emperor to kill it and save the remaining retainers. The kumiho of “The Kumiho and the Samjokku (Three-legged Dog)” (“Kumihowa samjokku”) is married to another Chinese emperor, and she shows vampiric tendencies in wanting to suck the blood from her intended victim, the hero of the tale (she is foiled by the hero's three-legged dog, who attacks and kills her).
Although this is by no means a complete survey of kumiho tales, it should suffice to supplement the brief definition we began with. Through these tales we can see just how intriguing a character the kumiho is, reflecting in its complex nature aspects found in various characters familiar to a Western audience: the trickster, the fiend, the succubus, and even the vampire. The kumiho continues to live on today as one of the few truly evil creatures of Korean folklore.
The legends tell that while the kumiho is capable of changing its appearance, there is still something persistently fox-like about it; its countenance changes, but its nature does not. In Transformation of the Kumiho (구미호의 변신), a kumiho transforms into an identical likeness of a bride at a wedding. Not even the bride's mother can tell the difference. The kumiho is only discovered when her clothes are removed. Pak Munsu and the Kumiho (박문수와 구미호) records an encounter that Pak Munsu has with a girl, living alone in the woods, that has a fox-like appearance. In The Maiden who Discovered a Kumiho through a Chinese Poem (한시로 구미호를 알아낸 처녀) The kumiho was ultimately revealed when a hunting dog caught the scent of the fox and attacked.
Although it is typically depicted as a woman when it transforms into a human being, the kumiho in the tale of The Maiden who Discovered a Kumiho through a Chinese Poem (한시로 구미호를 알아낸 처녀) turns into a young man that attempts to trick the maiden in marrying him. However, this is the only case in which it transforms into a man.
Although they are considered as having the ability to morph into other forms, the true identity of a Kumiho was said to be zealously guarded by the Kumihos themselves. There are also legends in which these transformations are said to be involuntary.
It is unclear at which point in time Koreans began viewing the Kumiho as a purely evil creature, since many of the ancient texts mention benevolent Kumihos assisting humans. In fact many of the older texts make more frequent mention of wicked humans tricking kind but naïve Kumihos.
As the mythology of the Kumiho evolved it was later believed that a Kumiho had to consume human hearts in order to survive. In later literatures they are often depicted as flesh-hungry half-fox, half-human things that wandered the cemeteries at night, digging human hearts out from graves.
Like all other Yokwe the Kumiho was thought to grow wise with age and with enough training, eventually learn to morph itself into various forms, including human. Thus they are often depicted as beautiful young maidens that trick unsuspecting men and later consume their hearts.
Another version was that the Kumiho must eat livers. This was due to the fact that the liver contained the energy of a human, meaning that it processes the food and gives energy, thus making it the container of the working force/life of a human. The fairy tale The Fox Sister depicts a fox spirit preying on a family for livers.
Another version of the mythology, however, holds that with enough will a Kumiho could further ascend from its Yokwe state and become fully, permanently human and lose its evil character. Explanations of how this could be achieved vary, but they sometimes include aspects such as refraining from killing or tasting meat for a thousand days, or obtaining a Yeoiju (여의주) and making sure that the Yeoiju saw the full moon at least every month during the ordeal. Unlike Yeoiju wielding dragons, Kumiho were not thought to be capable of omnipotence or creation at will since they were lesser creatures.
The idea of a beast becoming fully human is in fact quite heavily embedded in Korean mythology, such as the case in which a bear becomes a woman through a harsh ordeal in the Dangun mythology.