The Kingdoms=life/empires=death is confirmed. It's the Humans=Kingdoms/Fallen=Empires that I never heard any dev confirmation of.
The confirmation was made in this dev post:
There are 12 named factions (races) in Elemental. In addition, players will be able to create and submit their own factions to be shared by other users.
Each of the 12 named factions will have its own history and back story. Those factions are:
- Kingdom of Altar
- Kingdom of Yoren
- Kingdom of Gildren
- Kingdom of Tarth
- Kingdom of Capitar
- Kingdom of Ithul
- Empire of Uthugul
- Empire of Calax
- Empire of Turzog
- Empire of Izen
- Empire of Dol-Sirion
- Empire of Korin
The Kingdoms are of men, the Empires are made up of the Fallen.
So by combining these two pieces of information, we have Kingdom=Humans=Life magic and Empire=Fallen=Death magic. Now it's possible that this is only rigid in the campaign mode and that we'll be able to mix and match as we want in sandbox mode... I hope that's the case, anyways.
But what will really make it for me is if the types of things you can do with life vs. death magic are not largely divided by good vs. evil boundaries. Like Denryu said, being able to call on ancestor spirits and the like with death magic and other such things that wouldn't really fall under 'evil.' Likewise there could be ways to use life that would normally be considered evil... If they really make it so that you can't say "oh, life magic is good and death magic is evil" I'll be really happy!
The last thing regarding this topic is that I really hope they don't lock death magic sovereigns into having barren lava wastelands. Because if that's the case, I will hardly ever use death magic.