The Mists of Shadow

Comprising the Shadow Rift's actual border, the Mists of Shadow is the fog that envelops the domain. Remaining eternally closed so long as Gwydion] remains trapped in the Obsidian Gate, the Mists of Shadow make a person become less and less substantial as they encroach further into the mists, eventually reaching one hundred percent insubstantial and fading entirely away forever at a hundred feet inside. At any point before then, characters can turn back and regain their former forms.