I'm a librarian who loves anime, manga, and reading a wide variety of genres.
I think this is approximately where I stopped reading this morning. It's clearer now that, yes, this will work for the Ghost square, although the character still isn't quite what I'd normally think of as a ghost: Artifice is referred to as an artificial ghost and has the ability to take ghostly form and move through walls, but she spends most of her time solid.