Miasma

''Warning: Meta-Concept Page. ''

Miasma is the fallout of the magical nuke(s) released on Home over 10,000 years. It has recently receded, though some say it's actually pooled together somehow. It typically rests in valleys and deeper places. It sometimes moves, albeit very slowly.  

This stuff is Highly Corruptive in the way that acid is Highly Corrosive. It reacts relatively quickly with magic, causing spells and other items to go awry when near or in it. It also tends to mutate people, especially those with mystical abilities, working on their mind first. Finally, lands that have high concentrations of residual Miasma tend to *warp*. Locations change, distances, orientations, time... Places that were there the previous day simply vanish with no rhyme or reason - as if they're in sort of chaotic flux.

The Exim are known to have some control over Miasma, and there's verified reports of crystals that can keep one safe from the personal corrupting effects of the Miasma.

What the Miasma truly is will unfold as the story of Bastion continues to progress...