On your recommendation I snagged a copy of Primal Order, and as an exercise I'm statting up Zuggtmoy and Iuz. Alas, it's not as easy as one might hope.
We can calculate the approximate number of worshippers Iuz has, assuming they're basically all in his empire, and that he's supporting clerics based on the size of that population. He's a demigod.
Zuggtmoy has few worshippers on Oerth. Most will be on her home plane. How many is that? No idea, but maybe I can just copy the numbers from Orcus, maybe cut them down by half. She's a supported demigod on account of her ownership of the plane.
Both have minions, maybe 50 apiece or fewer. No servitors, at least one chancellor apiece -- Senshock and maybe Hedrack?
Zuggtmoy's chief weakness is that she is imprisoned, so she doesn't receive any benefit from her ownership of the plane, her worshipers on the plane, nor any base she stashed away on the plane. In theory players might be able to whittle down her primal, if they have overwhelming firepower, but they'll probably need the help of Cuthbert, or maybe Iuz (who desires her plane, as owning it would ascend him to supported demigodhood).
No ideas yet on what primal point value to give to the orb of golden death. Anthony, how did you come up with power ratings for artifacts? The orb of golden death is probably less powerful than the wand of Orcus. Maybe 1000 base? It's hard to say, and I wish the book had more guidelines. Zuggtmoy and Iuz split the cost unequally -- Iuz paid for a third or less. As far as I know, neither Iuz nor Zuggtmoy have any other artifacts.
No word yet on spheres. Iuz is definitely too young to have any spheres. No telling how old Zuggtmoy is. Her sphere is fungus, modelled on the sphere of equine creatures discussed in the book. If anybody here has more familiarity with Primal Order and the Temple of Elemental Evil, please, let me know what you think of my considerations so far, and especially let me know if you have any other suggestions, other Greyhawk deities stat'd up, or play reports using TPO with AD&D.
Thank you both very much, these comments were extremely helpful!
Some additional good discussions and links for further T1/T2 reading on the Knights & Knaves Alehouse at https://knights-n-knaves.com/phpbb3/viewtopic.php?f=40&t=17882
Allan.
A few quick thoughts, and do take all of them with a grain of salt---how you make your Greyhawk work is your call:
Zuggtmoy is a demon princess, so she's the equivalent of a lesser goddess in general terms (and in Greyhawk, the gods have vastly expanded powers/spells available than what's in D&DG; IIRC this list is reprinted in TOEE, but I'd compare it against the lists from Dragon Magazines #67 or #86 since the editing in TOEE was so bad); in Gygax's conception of the Abyss, she's one of the top 66 demon princes/lords, and among the top 6 among those
If you're looking for some more background on Zuggtmoy and her involvement with Iuz, she's part of the storyline in Gygax's Gord novels (in particular the second and third ones); you can also cherry pick info/details from Krista Siren's site at https://greyhawkonline.com/gordmain/
Iuz is served by his Boneheart (2 sets of 6 high-level evil NPCs, the first more powerful than the second; the first group included at least one archmage), and his secret 6 (evil demi-humans, I think one of each race), along with cults and such; he's a pretty major force in the Flanaess, although he is still still just a demi-god
Zuggtmoy's followers are less-well defined, but you can assume that most evil intelligent fungus creatures will worship her, along with some drow, and perhaps other races
Other artifacts for Iuz include his cape (although he may not have fashioned it, but perhaps stolen it or killed someone for it), and whatever mechanisms you feel he may have used to ascend to divinity (in the 2e Iuz the Evil book, I think they're termed his "soul husks" but I've not read that in ages), if you go that route
Iuz's spheres/domains in Greyhawk lore are: Oppression, Deceit, Wickedness, and Pain (1e); and Deceit, Pain, Opperssion, Evil with Domains of Chaos, Evil, Trickery (3e)
I hope that helps :D
Allan.
You've done good work there. Grodog might come in at any moment. I think you are correct that the PCs will need assistance from Cuthbert et.al. Primal puts them on another level. Your guidestone should be: what are you wanting the players to experience? To what end are you creating this stuff? You'll scale your stuff from there.