Kitsune

Kitsune are a race of female fox Yokai that are capable of transforming into humans with bushy tails.
== Biology ==
Kitsune have two physiological forms that they can shift between at will upon reaching maturity. The natural form that they are born into is that of an otherwise ordinary fox, albeit one that is born with a minor pouchlike structure beneath their tongue that contains their Star Pearl and with a varying number of tails. The second form that a mature Kitsune can take on is that of a human female with a number of tails corresponding to the number they possess as a fox along with a pair of fluffy fox ears. The specifics of the appearance of the two forms that a Kitsune possesses are unique to the individual and cannot be altered through any other known forms of shapeshifting magic, including many transmutational spells, but mundane makeup and beauty techniques can still be applied to either of them. 
All Kitsune are female but they are able to mate with males of some other species of Yokai as well as Humans; any male offspring they have will be the same race as their father while female offspring will be Kitsune. It is possible that Kitsune have identical twins, but they cannot have fraternal twins. Moreover, it is possible for Kitsune to reproduce via reincarnation through the use of their Star Pearls. 
== Star Pearl ==
Every Kitsune is born with a stone known as a Star Pearl that holds a significant portion of their soul. It is fatal for a Kitsune to lose physical contact with this pearl for extended periods of time. Within a matter of minutes of breaking contact, she will begin to suffer from the effects of becoming soulless before later becoming enfeebled and finally perishing. Furthermore, while Star Pearls are about as durable as diamonds, they are by no means indestructible and if one is destroyed, its owner will enter into a state of shock before succumbing to the ordinary effects of Star Pearl deprivation. For this reason, Kitsune usually try to keep their pearl safe beneath their tongue and will only take it out for the purpose of ceremony.
If a Kitsune dies while not in possession of her Star Pearl, the pearl will lose its luster and she will pass onto the afterlife as normal. If she is in possession of her pearl, then her pearl will absorb the portion of her soul normally housed within her body and function in a manner similar to a Soul Stone. This full soul-infused pearl is known as a Sun Pearl and is far more radiant than its Star Pearl counterpart and mana can be channeled into it in order to temporarily summon forth their spirit. If a Sun Pearl is consumed by one of the Kitsune's daughters, that daughter will become pregnant with a reincarnation of her mother and will be able to give birth to it. Such reincarnations always have the same number of tails that the original mother Kitsune had at her time of mortal departure.
An unfortunate quirk of Kitsune evolution is that twins are born with only one Star Pearl that must be shared between the two lest one or both of them be allowed to perish; when born, the two of them will be holding the pearl together in their hands. So long as one twin is touching the pearl and the other twin is touching the pearl's holder, by the Kitsune transitive property, they are both counted as touching the pearl and are able to survive. For this reason, Kitsune twins must always remain in direct physical contact with one another. If one of them dies while not touching their Star Pearl, the pearl will become inert and the other twin will soon suffer from the lethal effects of deprivation. If a twin dies while touching the pearl, their soul will be absorbed as normal and serve to empower their surviving sibling.
== Tails ==
Kitsune possess a number of tails that vaguely represent their supernatural capabilities. All Kitsune who are not incarnations of a previous life will possess a single tail whereas an exceptionally powerful Kitsune who has likely lived through many lives will quite possibly possess up to the maximum of nine.
== Psychology ==
There is a belief that exists in all species, "Our offspring are our immortality," and nowhere is this notion more apparent than among Kitsune. 
== Society ==