I really like Tharizdun, and am wondering where to find out more about him. I know there were a couple issues of Dragon/Dungeon that dealt with him and monsters related to him, but I missed them! Please help! Is he slated to appear in a new adventure soon?
Info on Tharizdun
Here's the Encyclopedia entry.
Zimriel's Tharizdun page is very useful for background and criticism.
Monsters associated with Tharizdun include the rogue eidelon MM2)
Check out WotC's The Cult of Tharizdun which contains info about Tharizdun's cultists and temples. It describes the Elhoriads, a kind of undead that guard Tharizdun's temples and even a sample temple.
Monster Manual IV contains a creature associated with Tharizdun called a Black Rock Triskelion which is only one kind of "avatar of Elemental Evil".
The Doomdreamer prestige class from Return to the Temple of Elemental Evil is described as "the elite among the ranks of the cult of Tharizdun". And the Entropomancer prestige class from Complete Divine could be associated with Tharizdun.
Also, I didn't see this listed as a reference in the encyclopedia but I figure the adventure "The Forgotten Temple of Tharizdun" (AD&D WG4) probably contains some good info.
-420
Tharizdun's demiplanar prison (the Demiplane of Imprisonment) is written up in Dragon 353.
I have Return to the Temple of Elemental Evil, and if memory serves, wasn't the (guarded and locked) entrance to Tharizdun's demiplane of imprisonment located right where they built the Temple, but on the Etheral Plane? I know that someone traveling Etherally can move thru normal walls, objects, etc. so couldn't someone who knew where the entrance was walk there Etherally (or even stumble or it by accident?) Or are the Temple's walls proof against such travel? I DON'T have the issue of the D&D magazine that describes the actual demiplane, however... is it pretty much empty with just Tharizdun in there, or does he have some nasty surprises in there with him too? Just wondering...
is Tharizdun a overgod? and is his power not the other god´s that give the power to demon´s and god´s priests ?
No.
Only the exterior of the demiplane is described in great deal, surrounded by a froth of manifest dreamscapes formed out of the surrounding ethereal protomatter. They're the dreams and nightmares of Tharizdun's worshippers, and potentially the thoughts of the imprisoned god as well. Lots of eyes, veined whirlpools, spiral motifs, etc.
The interior of the demiplane isn't described, but anyone touching its boundary risks being trapped within an extension of the plane (manifesting as a purple, crystalline shard), driven insane, or both. Getting out again is something else entirely.
Thardirzun, he is imprisioned in a demiplane.
As a god of entropy in Greyhawk setting, known adventures (like the all around known Temple of Elemental Evil) and books of this setting (like the gazzetter of Greyhawk) can give you more info about that dark greater god.