CoolDemon thinks it's hair and ears. Others think it is a hood, me included. But we won't truly know until we get a clearer picture of her. So until then, this discussion is futile and is merely running in circles, so I suggest we put it aside for now.
Alright?
Maybe instead we can discuss what role she might have. She appears to be a guide for Dante, maybe the one who summoned him to Limbo City to help her fight the demons who rule that place. From the trailers we've seen her in, she appears ethereal when Dante is facing the demons which might mean that only Dante can see the demonic plane. Like, the "human" plane is a veil that has been put up by the demons so no one will become suspicious, and Dante is able to look through the veil and see the truth.
I also wonder if she will have an active part of the game, as being part of the actual gameplay. Have any of you guys played Prince of Persia, the first game made for PS3?
In this, there's a girl who helps the Prince in several ways, as reaching high places and stuff like that. A sort of Navi or Midna to Link in the Zelda games. I think it would be cool if DmC went the same way, giving Dante this girl as a companion to help him do certain things he can't do on his own, instead of just being a story NPC. I'm always in for more playable characters. ^^
However, if the girl turns out to be a mere mortal human, I guess she won't be to much help other than just a mere guide...