Alrighty...here's the Vampire form for the character Zero I have:[link]
There's really not much to say about this one...except maybe the gauntlets. Basically, the bracelets he wears on his arms transform to turn into metal claws for him so he can slash things.
Those were my idea...and I'm really proud of them too! (they were a pain in the butt to draw, but they look cool...) Also, you can see his hair and eyes change color -- his eyes, if you didn't notice, are the same color as the streaks in his hair when he's in human form.
Plus you get to see how his blade turns out...and don't tell it looks like something from Soul Calibur, because I've been told that already. @.@ But as an idea for height; the top of the hilt comes to be slightly above his shoulders. And the reason why there's fire surrounding the sheath when he pulls out the sword...well...it's from hell.
That's the explaination my commissioner told me. ^^
So yeah, that's pretty much it...again, comments are loved, critique is desired.