Kitsune is the Japanes word for fox, but in folklore, in can refer to a fox yokai that can grow up to nine tails,which is called a Kyuubi-no-kitsune in Japanese. And they're known with their numerous tails, shape-shifting and illusion abilities. Each is born with one tail and grows a new one each year. They're often depicted wearing their famous masks. Kitsunes come in realistic colors of a fox.
Shape-Shifting: This ability is learn when a kitsune is around 100 years old about when they get their 2nd tail. But rarely it can be learned when they're 50, still having their first tail
illusion: Kitsunes make illusions to get away from things. Mainly to humans cause human are somewhat known to be fools (even me and you).
They also have the ability to go through a woman's body a possess them or either called "Kitsunetsuki" meaning "the state of being possessed by a fox". The fox goes through her fingernails or breasts. Sometimes the woman's face become a expression like of a fox's.
Sometimes kitsunes are depicted with a fondness of fried tofu. It's said that fried tofu is like junk food for kitsunes and can weaken, damage, or even unable make them use their magic and their abilities. There is also an udon dish called Kitsune Udon (fox udon) where they have Abura-age, which is sweeten deep fried tofu pockets.
Kitsunes are often depicted with their famous masks, which generally has fox ears, eyebrow marking, whisker, and a snout. There are variations of the mask, though
Each Kyuubi is born with one tail and when they get into the age of 800 years they have nine tails. They can only get nine tails. With nine tails they become very powerful and wisest of all, like a god but not a god. Their tails can be weapons making strong wind or hitting someone or something with them.
When a kitsune is possessing a huamn or in their human form, their shadow is shaped like a fox's. So I think they mainly hide their shadow as much a they can, such as trying not to go out in the sun. If behind a translucent screen, their silhouette will be a standing fox wearing clothes.