Continue reading only if you expect to be running (or reading) the Cyclopean Deeps. If you are going to be a player in this series of modules, Stop reading here.
Dammit, I mean that.
Okay, hopefully what we've got here is the group of people who won't be deeply affected by getting a glimpse inside the design process of Cyclopean Deeps.
Enter the new "boss monster" of the Cyclopean Deeps -- the Lord of Mists, the one, the only -- Isclaadra. He's in the Monstrosities book, for those who want to look him up. I'm not asking for help here with Isclaadra, and in fact he's a fairly well-developed bad guy in my own campaign. What I need help with is the details of his lieutenant demons. The original power-broker in the Cyclopean Deeps, Teratashia, had these demons called "darkswimmers" that were her leader-demons. With Isclaadra, I never developed his forces in that level of detail, just the human cultists.
I'm thinking something octopus-themed, given the association of the octopus ink with mists. That does potentially risk fart jokes, but, let's face it, all writing for fantasy games is essentially skirting the boundaries of Monty Python and fart jokes.
In any case, I'm thinking of something along the lines of the Shrroth demons from the Tome of Horrors, but they float in the air and are surrounded by demonic mists.