The Shadow World

Not sure if this is the right place to put this. It isn't a weapon or an element. What is it, then?
An attempt at world building.

I wrote a brief description of the shadow world in the thread Spell Brainstorming, and after I posted it, I have become more and more fascinated by the idea. While some characters may travel through the Shadow World via magic spell, other characters may find themselves there through other means.

The Shadow World is another dimension, one that is closely connected to our own. Everything is grey. There are no colors. Landscapes, buildings, bodies of water, and large objects are all present.

People, animals, and vehicles are absent. Small objects, technology, and anything of worth are also missing. It seems as though the bare minimum was used to construct this world. Buildings do not have doors or windows.

It is possible to alter the environment by bringing in supplies. However, these alterations do not apply to the real world. You could demolish a building in the shadow world, but it would still be standing in the real world. There are no plants native to the shadow world, but some have been introduced by travelers.

While no humans, animals, or plants are native to the shadow world, it is not quite empty. Spooks, humanoids with her black bodies, yellow eyes, and clawed hands, are native to this place. They collect anything that shines. They cannot speak (They don't have mouths) but they understand every language. They follow and attack those they deem weaker than themselves to take anything shiney from them. They are also willing to make deals with those strong enough to merit respect. Spooks are quite uncommon.

A rare wizard or two may also be found in the shadow world, whether traveling, studying, or living there.

And then there are monsters, trapped in the shadow world because they were thought to be too dangerous. Monsters are very rare, but very powerful.

Well, that's it. If you have any comments, questions, or some additional details of your own that you'd like to add, feel free to do so.

I find this idea very interesting.