They say you give up a few things, chasing a dream. In those mists that's the literal truth, for every dream of yours that comes true, a piece of yourself, mind, body, or soul, gets taken by the mist. Worst part is, you won't even know what the cost of your dreams are until you go to leave, and by then you might not even have a mind left to change...
A fragment of the mists of creation, drawn to those desperate to make their dreams come true. Suitable for any magical fantasy setting.
Many games draw moral lines in bold colors, where the real world is not so easy to categorize. Suppose that the player characters are faced with an overwhelming foe? Even unsavory allies such as orcish barbarians may be better than no allies at all. More disturbing, these allies may be honestly friendly to the PCs when all is done, overcoming barriers of race and religion. Will the PCs remain friendly with the bloodthirsty humanoid tribesmen when their mutual foes are defeated? Some would expect the tribes to betray them, but after the characters have honestly won their respect, even orcs may not be all bad.