Kitsune (狐) is the Japanese word for fox. Japan is home to two subspecies of foxes: the Japanese Red Fox (Hondo kitsune living in Honshu; Vulpes vulpes japonica) and Hokkaido Fox (Kita kitsune living in Hokkaido; Vulpes vulpes schrencki). They are also associated with mythical beliefs in Japanese folklore.

In Japanese folklore, these animals are believed to possess great intelligence, long life, and
magical powers. Foremost among these is the ability to shapeshift into human form; a fox is said to learn to do this when it attains a certain age (usually a hundred years, though some tales say fifty). Kitsune usually appear in the shape of a beautiful woman, a pretty young girl, or an old man, but almost never an elderly woman.
Other powers commonly attributed to the kitsune include
possession, the ability to generate fire from their tails or to breathe fire, the power to manifest in dreams, and the ability to create illusions so elaborate as to be almost indistinguishable from reality. Some tales go further still, speaking of kitsune with the ability to bend time and space, to drive people mad, or to take such nonhuman and fantastic shapes as a tree of incredible height or a second moon in the sky. Occasionally kitsune are ascribed a characteristic reminiscent of vampires or succubi — these kitsune feed on the life or spirit of humans, generally through sexual contact.
Sometimes kitsune are depicted guarding a round or
pear-shaped ball (hoshi no tama or star ball). It is said those who obtain the ball can force the kitsune to help them; one theory says that the kitsune "reserves" some of its magic in this ball when it changes shape. Kitsune must keep their promises or suffer a deterioration in their rank and power.
Kitsune are often associated with the
deity of rice known as Inari. Originally kitsune were the messengers of Inari, but the line between the two has now become blurred to the point that Inari is sometimes depicted as a fox. There is speculation as to whether there is another shinto deity who is a fox him/herself, but little historical evidence to support this. Kitsune are connected to both the shinto and Buddhist faiths.
The folkloric kitsune is a type of
yōkai. In this context, the word kitsune is often translated as fox spirit. However, one should not take this to mean that a kitsune is not a living creature, nor that a kitsune is a different creature than a fox. The word spirit is used in its Eastern sense, reflecting a state of knowledge or enlightenment. Any fox who lives sufficiently long, therefore, can be a fox spirit. There are two major types of kitsune; the myobu or celestial fox — those associated with Inari, who are presented as benevolent — and the nogitsune, or wild fox (literally "field fox") who are often, though not always, presented as malicious.
The physical attribute kitsune are most noted for is their tails — a fox may possess as many as nine of them. Generally an older and more powerful fox will possess a greater number of tails, and some sources say that a fox will only grow additional tails after they have lived for a thousand years. After that period of time, the number increases based on age and wisdom (depending on the source). However, the foxes that appear in folk stories almost always possess one, five, or nine tails, not any other number.
When a kitsune gains nine tails, its fur becomes silver, white, or gold. These kyūbi no kitsune ("nine-tailed foxes") gain the power of infinite vision. Similarly in
Korea a fox that lives a thousand years is said to turn into a kumiho (literally "nine-tail fox"), but the Korean fox is always depicted as evil, unlike the Japanese fox, which can be either benevolent or malevolent. Chinese folklore also contains fox spirits with many similarities to kitsune, including the possibility of nine tails. There is some evidence that kitsune are an imported icon from China, but further textual and artistic support for the argument that they are indiginously Japanese, dating perhaps as far back as the fifth century, B.C.E.
In some stories, kitsune have difficulty hiding their tail — usually the foxes in these stories have only one, which may be an indication that this is a weakness born of inexperience — when they take human form; the observant protagonist sees through the fox's disguise when the drunken or careless fox allows its tail to show.
Foxes also have a great fear and hatred of
dogs, and some become so rattled by the presence of a dog that they will revert to the shape of a fox and flee.
In Japanese folklore, the kitsune are often presented as
tricksters — sometimes very malevolent ones. The trickster kitsune employ their magical powers to play tricks on people; those portrayed in a favorable light tend to choose as targets overly-proud samurai, greedy merchants, and boastful commoners, while the more cruel kitsune tend to abuse poor tradesmen and farmers or Buddhist monks.
However, there is a second common portrayal: as a lover. These love stories usually involve a young human male and a kitsune who takes the form of a woman. Sometimes the kitsune is assigned the role of seductress, but often these stories are romantic in nature. Such a story usually involves the young man (unknowingly) marrying the fox, and emphasizes the devotion of the fox-wife. Many of these stories also possess a tragic element — they usually end with the discovery of the fox, who then must leave her husband. On some occasions, the husband wakes, as if from a dream, to find himself far from home, filthy and disoriented, and must often return to confront his abandoned human family in shame.
Many stories tell of fox-wives bearing children. Such progeny of human-kitsune marriages are always human, but they are generally held to possess special physical and/or supernatural qualities, which are often passed to their children in turn. The specific nature of these qualities, however, varies widely from one source to another. Among those who are said to have inherited such extraordinary power is the famous
onmyoji Abe no Seimei, who is said to be a son of a kitsune hanyō.
The oldest known story of a fox-wife, which provides a folk
etymology of the word kitsune, is an exception to the norm in that it does not end tragically. In this story, the fox takes the shape of a woman and marries a human male, and the two, in the course of spending several happy years together, have several children. She is ultimately revealed as a fox when, terrified by a dog, she returns to her fox shape to hide, in the presence of many witnesses. She prepares to depart her home, but her husband prevails upon her, saying, "Now that we have spent so many years together, and I have had several children by you, I cannot simply forget you. Please come and sleep with me." The fox agrees, and from then on returns to her husband each night in the shape of a woman, leaving again each morning in the shape of a fox. Therefore, she comes to be called Kitsune — because, in the classical Japanese, "kitsu-ne" means "come and sleep," while "ki-tsune" means "always comes."
Some have suggested that the origins of the word "kitsune" can also be ascribed to an onomotopoeia: "kitsu" was said to be the sound produced by foxes in Japan, much in the way "woof" is supposedly the noise dogs make in the West. "-ne" can be translated to mean "noise," and so the word "kitsune" can also literally refer to the sound produced by a fox. However, "kitsu" has not been used as representative of the sound foxes produce for some time, if it ever was; modern Japanese transcribes the sound of a fox as "kon kon" or "gon gon."

Kitsunetsuki (also written kitsune-tsuki) literally means the state of being
possessed by a fox. The fox was believed to enter the body of its victim, typically a young woman, beneath her fingernails or through her breasts. In some cases, the victim's facial expressions were said to change in such a way that they resembled foxes. Japanese tradition holds that the possession can cause illiterate victims to temporarily gain literacy.
Lafcadio Hearn describes the condition in the first volume of his Japanese Fairy Tales: "Strange is the madness of those into whom demon foxes enter. Sometimes they run naked shouting through the streets. Sometimes they lie down and froth at the mouth, and yelp as a fox yelps. And on some part of the body of the possessed a moving lump appears under the skin, which seems to have a life of its own. Prick it with a needle, and it glides instantly to another place. By no grasp can it be so tightly compressed by a strong hand that it will not slip from under the fingers. Possessed folk are also said to speak and write languages of which they were totally ignorant prior to possession. They eat only what foxes are believed to like--tofu, aburage, azukimeshi, etc.--and they eat a great deal, alleging that not they, but the possessing foxes, are hungry." He goes on to note that, once freed from the possession, the victim will never again be able to eat tofu, azukimeshi, or other foods favored by foxes.
Victims of kitsunetsuki were often treated cruelly in hopes of forcing the fox to leave. It was not unusual for them to be beaten or badly burned. On some occasions, entire families were ostracized by their communities after a member of the family was believed to be possessed.
In Japan, kitsunetsuki was a common diagnosis for
insanity as recently as the early 20th century. Possession was the explanation for the abnormal behavior displayed by the afflicted individuals.
Kitsunetsuki is also an
ethnic psychosis unique to Japanese culture, which causes its victims to believe they are being possesed by a fox. Some of the symptoms of kitsunetsuki are cravings for rice or sweet red beans, listeness, restlesness, and an aversion to eye contact. It can be considered a form of clinical lycanthropy.

Embedded in popular folklore as they are, kitsune have made appearances in many contemporary Japanese works. A few Western authors have also made use of the kitsune legends. In
anime, kitsune are sometimes depicted in a manner similar to non-furry catgirls, usually as female, seductive and fond of alcohol. Other depictions of kitsune include:
Neil Gaiman's The Sandman: The Dream Hunters is a short story featuring a kitsune protagonist, lushly illustrated by Yoshitaka Amano. Gaiman also mentions Kitsune briefly in his novel American Gods.
The series
Crescent Moon by Haruko Iida and Stuart Hazleton has a demon fox named Misoka Asagi as the unofficial leader of the Moonlight Bandits.
SNES/Super Famicom game Shadowrun features a female shaman named Kitsune. She can transform into a fox, which is also her totem animal, and is an extensive magic user.
In some
Legend of Zelda games, Keaton is a yellow 'ghost fox.'
Mega Man X Command Mission there is a set of secret bosses named OneTail through NineTails, and each looks like an anthropomorphic fox with the described number of tails.
Mega Man Zero 3, there exist one super-effeminate male character going by the name Kyuubit Foxtar, and he can creat some sort of 'tail', as many as 9 of them.
Ragnarok Online, the kitsune is featured as a powerful monster called a ninetails, and as a boss named Moonlight Flower.
Shippo from InuYasha. As a nod to the shapeshifting abilities sometimes attributed to kitsunes, Shippo is capable of taking many forms through use of a green leaf on his head, in the manner of the tanuki.
Ryutarō from
Pom Poko.
A shapeshifting kyūbi no kitsune named Sakura is one of the main characters of the anime
Hyper Police.
The spirit of a kyūbi no kitsune, called the
Nine Tailed Demon Fox (Kyūbi no Yōko), was sealed within Uzumaki Naruto, the main character of Naruto (Note: "yōko" is another name for the mythical fox creature). Naruto has fox-like whiskers on his face and has a prankster personality, one of such pranks involves his "Sexy Jutsu", in which he transforms into a beautiful naked girl.
Shuichi Minamino, the human alias of Kurama a main character of Yu Yu Hakusho, is a reincarnated bandit or thief kitsune named Yoko Kurama.
Konno Mitsune of
Love Hina is almost exclusively referred to as Kitsune due to her sly prankster nature, her fondness for alcohol, and her almost always closed eyes, which make her appear fox-like.
The story of the nine-tailed fox is told by Shuri Kurogane in
Ran, Akira Kurosawa's epic retelling of King Lear.
Stan Sakai's Usagi Yojimbo features a female fox character with the stage name "Kitsune," who is a trickster and master thief.
One of the two main characters of Andi Watson's comic Skeleton Key is a transplanted kitsune with a sweet tooth named Kitsune.
The protagonist of
Kij Johnson's novel The Fox Woman is likewise a kitsune named Kitsune.
White Wolf Game Studio's Werewolf: The Apocalypse roleplaying game features a race of shapeshifting fox-men known as the "Kitsune."
In the
Magic: The Gathering collectible card game, the kitsune appear in the Champions of Kamigawa block as a race of noble, plains-dwelling samurai and clerics.
Fantasy author
Mercedes Lackey introduced kitsune characters in her Serrated Edge novels.
An issue of the Psycho Circus comic book, starring the members of the band
KISS as cosmic beings, featured a story where a feudal-era samurai is trapped in a traveling circus populated by kitsune.
Miles "Tails" Prower, the sidekick of Sonic the Hedgehog, is a fox with two tails that enable him to fly.
In the hit anime
Rurouni Kenshin, Takani Megumi is nicknamed "Kitsune" and even portrayed as one in some episodes by Goro Fujita (Hajime Saitou).
In the series
Angel Tails (Tenshi no Shippo) there are two kitsune: Akane is a young benevolent guardian spirit, while her mother seeks to become a nine-tail fox and throw humans into a pit of fear.

The Kitsune Page
Foxtrot's Guide to Kitsune Lore folklore
Kitsune, Kumiho, Huli Jing, Fox - Fox spirits in Asia, and Asian fox spirits in the West An extensive bibliography of fox-spirit books.
Portal of Transformation: Kitsune in Folklore and Mythology

Anyway, who has almost all the credits of my gorgeous nickname is this awsome girl, Konno Mitsune from Love Hina:

Info obtenida de WIKIPEDIA, una de las básicas fuentes de información (ah, la neta la idea surgió gracias al ocio de Alos quien me paso el dato de la info, je je je)