Kitsune are "fox spirits," but the term is misleading: they are very much alive and very much physical. "Spirit," used in its Eastern sense, refers to a state of enlightenment. In the case of a kitsune, this enlightenment takes the form of cunning, knowledge, and the ability to take human form, which a fox learns to do when it reaches 100 years of age.
Any fox could be a kitsune.
The most visible trait that differentiates a kitsune from an ordinary fox is her number of tails. Kitsune may normally have as many as nine of them, and a greater number of tails is generally associated with a greater amount of magical power and/or a higher status. Younger kitsune often have trouble hiding their tails when they shapeshift; older ones apparently learn to overcome this problem.
There are two main types of kitsune: myobu, or celestial foxes, which serve and are associated with Inari, the god/goddess of rice and foxes, and nogitsune, or wild foxes, which tend to be more selfish, chaotic, and whimsical than their celestial cousins.
Nevertheless, myobu are not always benevolent or "good," nor are nogitsune necessarily malevolent or "evil."
Chinese huli jing have much in common with kitsune. Korean kumiho are also not dissimilar, although the Korean foxes are always evil.
Kitsune are generally accorded magical abilities. They are commonly attributed the ability to breathe fire or to create fire by rubbing their tails together, to create elaborate illusions affecting all five senses, to appear in the dreams of others, to possess others, and to see and hear things that happen far away.
Some tales accord them further power: the ability to take fantastic nonhuman shapes, to twist time and space, to drive people mad.
Kitsune are learned and wise. Kitsune are cunning tricksters. Kitsune are short-sighted, hot-blooded, and prone to be misled by their emotions. Kitsune are sensual seductresses, enthusiastic lovers. Kitsune are renowned liars, but they never break their word. All simultaneously. By the standards of classical Japan or China, fox spirits are maddeningly mercurial.
They tend to be driven by desire, whether that desire is intellectual, physical, or emotional in nature. A fox may spend a great deal of time in idle revelry, but once she decides on a course of action, her dedication is surprisingly steadfast.
All kitsune, even males, have an essentially feminine nature. By Chinese reckoning, they have an overabundance of dark chi, or yin energy. Many stories involve a fox draining the vitality — the white chi or yang energy — of her male partner during lovemaking, much like a succubus. Some say the fox uses this energy to add to her power; others, to further her enlightenment.
Sumire is a nine-tail, but often wears only one. She's more or less a full shapeshifter, although she's claimed to need to "study" to make a form authentic. She's shifted her clothing, which suggests that it's probably illusionary, or perhaps a part of her in some way.
Sumire is nogitsune. She's connected to flame, light, and chaos — the forces of creativity and destruction. She's conjured globes of light and tongues of flame. She hasn't possessed anyone, yet, but she's apparently appeared in a dream or two.
Sumire's Freedom is not a kitsune quality, but a personal one. It does complement some of her abilities. It might inhibit others.
Sumire's personality is heavily influenced by her nature. She's playful, wise, hedonistic, deceitful, philosophical, foolish, mischievous, lustful, honest, capricious... somewhat at random, and she sometimes changes during the course of a single conversation. The only constants are that she's curious and agreeable; she rarely says no to sex. Or to challenges. Or requests of any other sort, for that matter.
Why? And does it matter?