I don't really know enough about dimensions to even say if the ones I know of at home are connected or not. Magically they must be, but I have no idea if it's more than that.

I can't travel between the dimensions, but some of the magicians of old can. Partly at least. Their forms in the living world are only temporary, and are more magical constructs than an actual body.

[Those magical constructs can still hit pretty hard though. When they show up it usually results in a serious ass kicking for Devon.]