Editing Setting:Brighthammer 40,000/Warp Horrors (section)

=== The Screaming Fog ===
When the speck of hatred that made up the core of the Destroyer disappeared, not all Warp Horrors and Psykers that it consumed over the millennia could manifest again. Those that could not are doomed to drift in the currents of the Warp as some kind of fog. While the fog itself is unable to consciously act, it is easily manipulated by rogue or careless Psykers; however, prolonged contact with it invariably drives living minds completely and utterly insane. 

Should a mad or careless Psyker manage to locate and consolidate a sufficiently large amount of fog (which is no small feat itself), the world they reside on is utterly doomed. People will be driven mad, the dead will rise from their graves, the stars will change, ships will fail to reach the planet in time to avert disaster, even some other Warp Horror might be drawn to the Psyker.

The fog itself cannot be destroyed, but the destruction of its vessel forces it back into the Warp, where it is again a helpless victim to its currents.