A WIP shot of a reference sheet for a character I have in my second pathfinder campaign based around a medieval Asian theme. So far she's gotten to level 4, choosing magical tails for all her current feats so far.

In my little head-cannon and with permission from the DM, Kitsunes who become more magically inclined slowly start to turn the shade of their specialty. In this fox's case it is the divine, rendering her white. When she's fully awakened, she will be completely white except for her eyes. Even the inside of her mouth will become paler.
Her strength in magic, or level of 'awakening' is expressed by the extent of her fur turning white, and how many magical tails she has gained. The process of the tail splitting is exceedingly painful, as the kitsune will have a tail momentarily engulfed in fox fire and the bones will split and literally rip itself in two down the middle before healing and fluffing back up to form two new tails, the fire itself does not harm the fox.