After doing some research, I've come to the conclusion "Z" is a Kitsune.
http://en.wikipedia.org/wiki/Kitsune
Reasons:
1. The name of this movie is: "Ruler of Illusion". Kitsune's are capable of assuming human forms. In this clip, you can see Ash face to face with who I'll refer to as "Dark Ash".
http://www.youtube.com/watch?v=lWo9zOKjYo8&feature=related < link here to what I'm referring to.
2. Looking at the model, I believe these to be tails coming from its head instead of one large clump of hair. Kitsune's are known to have 1-9 tails, so it may or may not have more than 7. It is not possible to tell from what we are currently given.
3. Face shape, claws, paws, etc. Not a very strong supporting reason, but they are details that need to be looked at.