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.

The Lady, which is depicted either as a ten-tailed kitsune, or a thousand-tailed kitsune is supposed to be the mother of the kitsune race, and all serve her in one manner or another.
 

Behavior

Kitsune follow their own code of ethics, though they adapt the morals of those around them, more for the sake of being accepted than for any other reason.

Unless they are myobu, they can be both allies and enemies to the mortals around them. If someone offends what a kitsune considers 'correct', they can become evil, malicious, and disruptive. If someone behaves according to their ethics, they will become polite, kind, and helpful.

This contradiction is evident in the sheer number of legends of kitsune, how they were feared and hunted on one hand, and revered and worshipped on the other. There are legends of kitsune guarding samurai for a favor done, while there are others of kitsune taking the desired lover of another samurai. There are legends of kitsune aiding the peasantry, while there is another of a kitsune stealing food from a lowly traveler.

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.

Role

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.