Yōkai

The Japanese take their Yōkai Studies very seriously. There are universities with small departments devoted to spirits, demons, exorcism, etc (seperate from "Religious Studies"). This should not be too surprising since the Vatican still quietly maintains a small group of trained Exorcists, and local Catholic Priests continue to perform "House Blessings" upon request.

The common translation for Yōkai of demon does little to convey the complex nature of Supernatural beings in both Feudal and Modern Japan.

various translations are: "bewitching apparitions", "apparitions", "spirits", "demons" or "supernatural being which is not a Kami nor a ghost"

Wikipedia notes Youkai as:

Yōkai (妖怪, Yōkai? "apparitions", "spirits", or "demons", also Romanized youkai, yokai, or yookai) are a class of obake, creatures in Japanese folklore ranging from the evil oni to the mischievous kitsune or snow woman Yuki-onna. Some possess part animal and part human features (e.g. Kappa and Tengu). Yōkai generally have a sort of spiritual or supernatural power, and so encounters with human beings tend to be dangerous. Yōkai also have different motives and agendas from human beings, which are often completely incomprehensible.

Some modern stories tell of yōkai breeding with human beings to produce hanyō. A classic example of such a union is the Historical figure Abe No Seimei of the Heian era. It was claimed that this famous magician/astronomer/sage/alchemist was born of a human father and a Kitsune mother named Kuzunoha. Clearly talented, at an early age he was able to command weak oni. Seimei was sent by his mother to Kamo no Tadayuki (a master of onmyodo) so that he would learn to live as a human and not become evil.

Japanese folklorists and historians use yōkai as "supernatural or unaccountable phenomena to their informants". In Edo period, many artists, such as Toriyama Sekien, created a lot of yōkai inspired by folklore or their own ideas, and present day not a few yōkai created by them (e.g. Kameosa and Amikiri, see below) wrongly considered as a legendary origin.

From metropolis.co.jp we find:

In the 1780s, scholar and artist Sekien Toriyama trawled through folklore, myth and rumor to compile The One Hundred Demons Night Parade, an encyclopedia of supernatural beings residing in Japan. Toriyama divided Japanese spooks into several different categories. Most of these bizarre characters are immediately recognizable to people today:


 * Yurei are the most similar to the Western concept of ghost - spirits of the deceased, wearing white kimono, their visible bodies ending at the waist. They are drawn back to haunt the living from unrequited love, or sometimes, hunger for revenge.


 * Yokai are living but non-human creatures such as Tengu, the phallic-nosed goblins who grace hundreds of izakaya menus. There are also Kappa, reptilian beasts living in isolated lakes, the cannibalistic Oni Babaa, and the Yuki Onna, with her kiss of frozen death.


 * Oni are taken directly from Buddhist theology. They are the fearsome fanged and horned demons whose images are found carved near temple entrances. They have specific duties, such as rescuing the innocent, scaring the wicked to death, and guarding the gates of Hell itself.


 * Fushigi na Dobutsu are mischievous animal spirits, of which the most notorious are the foxes. Foxes are regarded with distrust and suspicion; they are believed to be able to transform themselves into human shape and possess the unwary. Shrines to appease the fox god Inari can be found all over Japan.


 * Mononoke are what in English we'd call poltergeists, though they owe their history to the Shinto belief in every physical object - stones, trees, machines - having life and consciousness. This has led to countless stories of screaming stones, shoji doors with staring eyes, and domestic tools that move and persecute their owners.

If you suspect that your 2DK (ed note: refers to a 2 bedroom apartment) may shelter a fox ghost under the futon, don't panic! A large number of exorcists, both Shinto and Buddhist, work in Japan. A Buddhist exorcism is performed by a temple's chief priest and his assistant, reading an appropriate sutra (the scriptures of Buddhism) and burning a special incense. The priest also carries a shakujo - a wooden staff with metal rings threaded onto it, creating an unearthly sound to scare evil spirits away.

The Shinto exorcist works more at prevention than cure. This is why buildings of public use - factories, government buildings, restaurants, pachinko parlors - have a Shinto priest perform a special rite of purification on the land before construction. It's not only on Japanese soil that these ceremonies take place; Toyota flew a priest as far away as Newcastle, England, to bless a new car factory.

please see SuperNatural Beings of Japan an ongoing work for more details.

In this article, we deliberately exclude the class of creatures called Tsukumogami, since they are common household items such as candle lanterns, umbrellas, shoes, sandals, scrolls, etc. that have somehow taken on a life of their own - traditionally after having existed for one hundred years. below is a small list of non-human creatures appearing in InuYasha, (excluding Tsukumogami) - please note that there are often both benevolent and evil aspects of many:

Yurei: "Ghosts"
InuYasha Example: the "Un-Mother" in episode 5.
 * The Noppera-bō (のっぺら坊): faceless ghost, known primarily for frightening humans, but are usually otherwise harmless. They appear at first as ordinary human beings, sometimes impersonating someone familiar to the victim, before causing their features to disappear, leaving a blank, smooth sheet of skin where their face should be.

Spirits of women who have either died in childbirth, or died without making sure that their children have been provided for. Ubume address a common concern in Japan; that of a mother's duty toward her children. Appearing in the form common to most Japanese ghosts, they wear robes of white, and have long dishevelled hair.
 * Ubume (産女):

Youkai: "spirits", "demons"
Mountain Ogres - hideous giants with sharp claws, long horns and wild untamed hair. Generally humanoid but occasionally they are shown with odd numbers of eyes or extra fingers and toes. Their skin color is usually red, blue, black, pink, or green. Oni typically wear tiger skins and carry fearsom iron clubs called kanabō (金棒, kanabō?). In the earliest legends, oni were benevolent creatures who fought off evil and malevolent spirits. Later they became associated with the spirits of the dead, of the earth, of the ancestors, of the vengeful, of pestilence, or of anger and malevolence. Two Oni guard the gates of the underworld ( seen in episodes xx to yy in Inuyasha).
 * Oni:

A Water Demon with webbed hands and feet, a turtle shell, and a circular dish on top of its head. It can exist out of water only as long as the dish contains water. About the size of a small child, the Kappa is very strong. It attacks horses, cattle, and humans, dragging its prey into the water, feeds on their blood, or drains their life force, (etc) leaving nothing behind except a hollow gourd. It is said to sometimes drag unwary travelers into the water and drown them.In many localities, drowning is still referred to as GAPPADOKO. When benevolent, the Kappa is supposedly a skilled teacher in the art of bone setting and other medical skills. The Kappa is always portrayed as trustworthy despite its many evil ways. When captured and forced to promise never again to harm anyone, the kappa always keeps its promise.
 * Kappa:

Fox Demon. one of the HENGE (Shape Shifters). The Kitsune most often appears as a woman to human men or as a man to human women. Often wishes to merely play pranks, but sometimes desires to mate with humans. generally harmless. InuYasha Example: Shippo is a young Kitsune. spirits summoned to serve or protect an Onmyoji, much like the European wizard's familiar. Shinto priests and some miko also are capable of summoning shikigami. Shikigami can appear as birds, small animals, or humans. The range of abilities possessed by a shikigami is dependant on the Onmyoji's capabilities. InuYasha Examples: The Red and White Priestesses (episode 63) - they utilize paper Shikigami both as miniature "helpers" and to create the fake Inuyasha and Kagome monster-puppets.In the series of episodes 149-151 featuring the "unknown saint", Kikyo makes use of another tradional example of Shikigami Helpers: Kochou and Asuka
 * Kitsune:
 * Shikigami (式神):

racoon dog youkai. one of the HENGE (Shape Shifters). The Tanuki is fond of drink and food to excess, often trick humans by purchasing sake with leaves disguised as money. Tanuki are generally harmless tricksters - but their tricks seem to escalate if the one being tricked merits it. Miroku's companion Hachi is a tanuki.
 * Tanuki:

one of the HENGE (Shape Shifters). a long-nosed mountain and forest spirit with a beak and wings; part crow, part man, some were said to mimick mountain priests (yamabushi)- these were portrayed as being more mischievous than evil and were often depicted helping people. Others were said to always be trying to snag an unwary traveler or plump monk to eat. Their main abilites are the ability to speak to humans without moving their mouth, the magic of moving instantly from place to place without using their wings, and the sorcery to appear uninvited in the dreams of the living.
 * Tengu:

cow-demon - This creature is said to have the head of a cow and the body of a crab or spider.
 * Ushi-Oni (牛鬼):

snow woman - Yuki-onna is winter personified; beautiful and serene, yet ruthless in killing unsuspecting mortals. In many stories, Yuki-onna reveals herself to travelers who find themselves trapped in snowstorms and uses her icy breath to leave them as frost-coated corpses. Other legends say that she leads them astray so they simply die of exposure. Other times, she manifests holding a child. When a person takes the "child" from her, he or she is frozen in place. Parents searching for lost children are particularly susceptible to this tactic. An InuYasha Example of Yuki-onna is the demon eencountered by Miroku is episode 101, Seven Years Later: Lingering Snow.
 * Yuki-onna (雪女,):

--- Notes:

Yura Of The Hair (episode 4) is a specific example of a spirit or demon that exists in a comb that was used to comb the hair of the dead. Over time, the comb absorbed the "negative energy" of many dead who were not reconciled to their passing.

Another example is ""Terror of the Ancient Noh Mask'' (episode 11) with the variation that the Noh Mask became animated only through the embedded Jewel Shard.