You can shift? You've probably got a flock of them then, that sort of thing usually gives off energy like a leaky warp core, you're probably lit up like a Christmas tree as far as the Shadows are concerned. I'll have to ask around, might just be you've got shy ones, of course, it might be that you're from a world without them, it's weird, but it does happen.
I don't figure the island was extra-dimensional, just small and uncharted, there's a lot of those still.
I might actually have to look into that, hadn't thought about it before. Of course, I'll have to talk to the Shadows themselves, see if it's worth it to try and let people know about them.