[Gandalf Parker]

Here is some about nations from the Wikipedia link on Dominions 3:

The nations in the game are based upon world history and mythology, rather than standard high fantasy races such as elves and orcs. Amongst others, the mythologies of ancient Greece (Arcoscephale), Rome Republic (Ermor), East Rome (Pythium), Sarmatians (Sauromatia), Egypt (C'tis), Medieval France & Spain (Marignon), Medieval England (Man), Ireland (Fomoria, Eriu, Tir na n'Og), Scandinavia (Vanheim, Helheim, Jotunheim, Midgard, Utgard, Nieflheim), Germany (Ulm), China (Tien Chi), Africa (Machaka), Japan (Jomon), Aztecs (Mictlan), Rus' (Bogarus), and India (Kailasa, Lanka, Bandar Log, Patala) are represented. Other nations are based on the work of recent writers, particularly H. P. Lovecraft (R'lyeh), or Abysia, that looks loosely based on Yezidi faith, as it contains Melek Taus in its list of random general names and is mostly associated with holy flames, beings of flame, fire worship and magma, or Hinnom, which is based on Semitic mythology, featuring Nephilim.

Somewhere around here there are a couple of threads discussing it all also. Kristoffer, the developer who did most of the thematic stuff, even jumped in and commented a few times. I wish I could give you the links but to be truthful the conversations lost me in the first couple of posts. Too deep and too much history for me