[quote=@Bishop]
This could be another one of the theories explaining one of his powers.

Well the main gist of it, seeing as he is darkness incarnate, [b]he is Darkness[/b], where ever that absence of light may be, he is there. He is the will of Darkness, an extension of it and as so anywhere there is darkness there he is. Absence of light = him where ever that may be, in any dimension where light is absent, even in some small parts. So basically he is just the concentrated will of Darkness. If it chooses so he can be focused on another part of the [b]whole[/b] and reappear there.

And I expected every living being to have a projection of their spirit/soul on some parallel realm to the physical one. What happens to said creature when it leaves its physical dimension to a dimension without a parallel spiritual realm? Can people and things live without their soul? 
[/quote]

Soul is mind, will, and emotions. So, yes, but they'd be a vegetable. The biggest problem I see is that saying someone embodies the absence of light [i]everywhere[/i] is like me saying I can embody the absence of Cthulhu everywhere. Same principle, just with a less common medium.