The picture certainly doesn't do it justice as that black fog is a moving volume i think. when i turn around (aiming the opposite direction to the shot) its equally dark yet if i look side to side its possible to navigate.

Its probably one of the few things about this game i am kinda like "wtf m8" at.
especially because it blacked out a greydwarf on the right of the picture.
you literally can't see it and i kinda feel that's a bit of a problem no matter how short this lasts.

I have noticed they use this same effect for when Odin shows up too, it really works for that particular application. freaked me out in a good way hahaha