[Sombre]

I've got a great one for you. An atheist nation. They have no sacreds, obviously, instead they have various weapons and spells that make sacreds largely useless against them by using the bane of heresy, halt sacred etc weapons and abilities. Rather than priests they have heretics, in fact most of their commanders are heretics, reducing dominion where they go. Of course they keep dominion in their cap - they just try to reduce it to 0 everywhere else.

And the big reason they want to reduce dominion to 0 or as low as possible everywhere else is partly because their commanders domspawn liability units - religious scroungers and conmen that can't do much of anything useful, but cost a whole lotta upkeep.

They have a special immobile pretender with a very high level of holy magic in order to preach at their home town and keep the dom up there.

They don't have to be human based at all - in fact they might be better off being very alien indeed, since they are so strange compared to other dom3 nations.