So I've been thinking about how to merge Greyhawk and Blackmoor for some time and also been looking on these boards for different takes to do it. Originally I generally just wanted to have a bit more cohesion for playing classic adventures from both lines while still using much of the same lore and places for the specific adventures. Maybe I been thinking about this backwards. Instead of melding Blackmoor as it is in it's current state into Greyhawk, with all the canonical problems to iron out, why not instead rather merge bits Greyhawk into Blackmoor instead?

The larger world of Blackmoor is not very detailed. We got Thonia which I rather refer to as just The Great Kingdom founded by King Robert l. Let's say that this Great Kingdom have a very similar geography as Flanaess. In this Great Kingdom the Nyr Dyv lies on the approximately the same place . And on the southern side of it lies the Domain of Greyhawk . In my campaign I would probably use the Yggsburg version but one could just use TSR Greyhawk according to ones fancy. One could then in a case by case basis add in different parts of Oerths realms into or bordering this Blackmoor Great Kingdom.

Personally I would put the Imperial province of Mohacs about the northwest side of Nyr Dyv. So the imperial capital a bit closer to Blackmoor in my campaign. Thus Furyondy will be the the heart of the Great Kingdom. Veluna, Duchy of Urnst, Perrenland etc would have more or less similar locations as in Flanaess. There would be no Empire of Iuz. I would also put in Geoff and Sterich as remote provinces of the empire to the west. The Empire also have colonies around the Azure sea in the tropical regions.

Some scattered thoughts:

Visit to Temple of Elemental Evil? Check.

In the remote province of Geoff giants ravage the lands and yet the Emperor does nothing to aid. Strangely same behavior as dealing with the Blackmoor situation. Fighting giants in Geoff? Check.

Exploring the ruins of Castle Greyhawk? Check.

Maybe the the Beagle/City of the gods picked up a strange signal from the Barrier Peaks it was supposed to investigate before it crashed? Check

Why does emperor Iyx I seems so uninterested in the invasion of the Zugzuhl worshipping afridhi? Is it just plain madness or rather infernal corruption perhaps? Rumors spreading through the empire of rebellion in different provinces as a reaction to the emperor's irrational behavior. Some say Iyx I shows great favor for a certain fire cult growing in the Imperial province of Mohacs. Or maybe he have a wormtongue in the form of an emissary of The Egg plotting the downfall of Blackmoor and the afridhi is an means to and end?

In this world Zugzuhl and/or the Egg could take a similar place as Iuz have in Greyhawk. Not yet any lands beyond Blackmoor, but still trying to influence realms beyond.

Those ideas sound pretty good.

I could see merging the Afridhi and Iyx, but perhaps it would be better to merge Iyx with The Thonian Rand and the Iron Duke?

-Havard

Well, if you are looking to create your own mix and match world, then you might want to go back to the "Domesday Book" C&C society map, and for that you might like the "Blackmoorized" version I drew up here

You can take that and "fill in the blanks" however you please.