@boiga:
I don't think so. Because her power allows her to manipulate things outside of her own body (the ghosts,) Perona must have a logia type power. Logia devil fruit users can only control one unvarying element (likely ectoplasm in this case,) and thus she probably can not have different "kinds" of ghost.
My question is whether she's a logia like ace, crocodile or smoker whose bodies physically transform into thier element, or if she is like Blackbeard and possibly aokiji whose bodies remain in human form while they manipulate their element around them. In the scene of her ghost returning to her body, it looked like the body was there already waiting for the ghosts. If this is the case, then her body will likely be Perona's only weak point. If her physical body can turn into a ghost, I don't see how she can be harmed.
I wouldn't take those ghosts as an element if I may, they seem more like products of her ability alone and have a job of their own. I also doubt the view that it's her only ability, as we were shown a new ability to almost any other major fighter each arc, for whatever reason. I don't think I need to list examples, right?
One thing I always wanted in One Piece is that some DFs will have limitations and requirments they have to fill. For example, Flamingo being able to manipulate only 2 people, but can manipulate them for stuff that Oda can choose. Like that, Perona's ability is to produce ghosts, or only one ghost, that duplicates while dancing. And the difference between getting a positive one or negative one is simply luck. That adds a little color to the opponent too, I think it's better than having a ultimate power like the rest of the opponents so far.
@onemoment:
Actually, I think that Blackbeard can transform his body into his element. It's just that his element doesn't actually let attack pass through him, but rather absorb them. He's a black hole.
Not really, pay attention to how "special" BB's DF is, as he says it. It allows him to spread his "darkness" around, and manipulate the gravity it conducts. It's no black hole, it's gravity. And it grants him that power under the condition he won't be able to dissolve [sp?] like other Logia. Kinda like the limitations I mentioned above.
This is also for this quote by boiga:
Now that Oda has introduced one logia type that can not transform their body, there is nothing stopping him from developing others with a similar weakness. If Perona's body can not transform, she would also be unique among logias for the distance at which she can control her ghosts and the fact that her consciousness travels with them.
So yeah, after Oda said what he said about BB, he actually created a wall for himself for not doing anything similiar. If he will [and he can do it with at least one more], it will only get BB's so-called amazing ability to be more like a normal one. One that he searched and killed years for.
On another view, though, I don't see what's the problem with having a logia for both positive and negative ghosts. Now that I think about it it's almost bound to happen, at least for me.