Gleefully taking my own advice, one of the many ideas I have stolen from James’ Dwimmermount campaign is azoth, known to my players as liquid magic. As I have worked this week to prepare a Brain Lasher city, azoth and its origin in quintessence have played a very large role.
The first question that I asked of myself when detailing the city was: to what purpose was this city built? What was the reason Brain Lashers wanted to live here en masse? (Thus, despite the weirdness of the environment, my own tendency toward Gygaxian naturalism rears its head). The answer: azoth.
Unlike in Dwimmermount, where azoth mysteriously rained down on various planets at some point in the past, the existence of azoth in my campaign is quite deliberate. The Brain Lashers “mine” it from various suitable dimensions. It is a very laborious and slow process, but, given the powerful qualities of the end product, (especially since it is almost entirely accomplished by slave labor) they see it as quite worth their while.
I am also putting a subtle Christian spin on the story. Since Brain Lashers have a visage not unlike Cthulhu it should come as no surprise that they (knowingly or unknowingly) serve the demonic outer gods. Thus, their efforts to mine azoth from the quintessence has the negative consequence of literally tearing holes in creation — thus speeding it on its way back to the nothing from whence it came (a little Christian dogma, there).
These holes are the myriad portals my players have found in various parts of my campaign world (though they have yet to voluntarily step through one). Thus, the portal that the party expects to find in the city is actually the very place the Brain Lashers are mining azoth.
9 hours ago