[Endoperez]

Would you keep Ulm with the vampiric influence, or would you rather have the secret order take over the whole nation? Local counts and nobles and such would claim they're in power and there would be no visible leader to the land, but everyone would have at least one Member of the Second Tier close to him.

Agarthan humans would have run out of both statues and corpses of the inhuman Agarthans, so I don't know what would be left for them to revere. Perhaps they'd inherit earlier Ulm's craftsmanship and become neo-dwarvish society of underground metalworkers. In game terms, even if it's different, Agarthan city/town is probably the best way to have an underground shop/inn/training area (as a roguelike, I imagine it will have vast and deep dungeon complexes).

Abysia would probably be a nation of humanbreds, with just a "ruling family" of Abysians, or at least humanbreds who claim to be closer to the Abysian bloodlines. The rulers would be some kind of priest-kings, and the nation would probably be the main source of Sceptres of Authority/Wands of Wild Fire/Rods of the Phoenix. Sceptres would probably mark a community leader, while Rod of the Phoenix could be a very rare quest item. Speaking of combat styles, some kind of Abysian two-dagger-fighting remnant of the assassin cult should be available.

Pangaea would probably not exist as a nation or even cities/towns. Centaurs would serve as high-ranking warriors, satyrs would travel around as rogues rather like Dragonlance kender, dryads would be rare priestesses and nature mages and objects of worship by the common humans. Minotaurs would be rare, probably all some kind of Grove Guards, or perhaps bodyguards for the dryads. Panii would have mostly disappeared.

Will you have any underwater races? You could just say that the dreamlands dominion depopulated all the seas, and the death of their god killed all the remaining illithids, tritons, dreamers and most Atlantians. The few remaining atlantians would be in the far north and only rarely heard of.

Perhaps a Gath-Jotunheim war (fire giants vs frost giants) could have broken out? I don't know if that's a good idea, though.

Vanheim would be Sweden, but closer to the 30 years war time. Swedish cavalry was reformed and had superior tactics for a while there; they charged firing their pistols, changed to swords at the last moment, cut and trampled and devastated their enemies, and then returned to where the accompanying squad of infantry kept them safe from counter-charges (with pikes and muskets). They could be a small nation that has recently conquered Milesia (Eriu) near the kingdom of Man. Tuatha and Vanir both changed the people under their rule, so even with the Vanir almost nonexistant the new Vanheim could be the last land of truly wild magic, with Amulets of Lycanthropos and Air buff-spells and minor charms more easily available, and most important people having fey ancestry or tendency to change shape during full moon, or at least some magical tricks up in their sleeves.