Fiend Folio World: Llurb Tdunon

(Apart from any errant travelers who may happen upon the world, Llurb Tdunon is entirely made of Fiend Folio creatures.  Feel free to check out the Fiend Folio-only encounter tables that accompany this world.)

Set in the same star system as Rockulon Prime, Llurb Tdunon is an enormous world (albeit with Earth-strength gravity), hundreds of thousands of miles in diameter.  (In Spelljammer terms, it's a Size H, Type E spherical world.)  Llurb Tdunon is a savage land of tundra, desert, forest, and jungle.  Like Rockulon Prime, Llurb Tdunon's development was also influenced by the coming of the Space-God.  Unlike Rockulon Prime, Llurb Tdunon did not play host to the dead-but-undying deity's corpus, but rather, the planet was infused with large quantities of the Space-God's blood (so much so that it has a somewhat ruddy hue, and even has a series of red rings, formed by frozen blood droplets).  The quantity of deific blood prompted both strange evolutionary lineages as well as the proliferation of extraplanar portals.  Various outsiders — such as githzerai and githyanki, slaads, and even the occasional devil — roam the landscape.  It is said that the Princes of Elemental Evil even roam the landscape in material forms.

The natives, largely ignorant of the mythos of the Space-God, instead worship the strange outsiders that have come to be known on this world.  In addition to the Princes of Elemental Evil, the planet's inhabitants are also known to worship Ssendam, Lord of Insanity, and Ygorl, Lord of Entropy.  While many of the planet's drow worship the Princes of Elemental Evil, some have turned to the heretical worship of Lolth, Demon Queen of Spiders.  (Oddly, apart from retrievers, there aren't really any spider-like creatures on Llurb Tdunon.  Scholars think the local populace either treat the spiders as mythological creatures, or that some of the drow originate off-world and brought spider lore with them.)

Note that the good races typically also worship these deities, although their prayers and sacrifices are largely rituals of placation, and they tend to worship different aspects of the deities.  The Princes of Elemental Evil, for example, are venerated simply for their connection to natural forces, while some clerics refer to healing spells as "The Closing of Lord Ygorl's Eye," referring to the idea that the Lord of Entropy's ignorance allows growth and healing to happen.

All-in-all, Llurb Tdunon is a savage land populated by monstrous humanoids and weird creatures.  Barring visitors from other worlds and planes, native sapient races include creatures such as aarakocra, bullywugs, dakon, drow, flinds, githzerai, kenku, svirfneblin, and the like.  With no native unifying race, the races tend to be insular and largely keep to themselves.  (Adventuring parties composed of humanoids, however, occasionally occur.)  As such, cities tend to have lots of untamed land between them, and they tend to organize along racial lines.

(Parties interested in the background of Llurb Tdunon may wish to read about the development of Fiend Folio encounter tables.)