To be fair I do not know much of xuhrl-njok culture(s) besides them being sociopaths, and purely self-oriented (in which the aforementioned sociopathy plays a part)... That xuhrl-njok are highly intelligent, that I didn't doubt - just look at their magical capabilities, and I don't mean sheer prowess here -, but I guess I mostly imagined their sociopathic selves to be either fairly solitary or make temporary small groupings for when it currently happens to be useful for them (or a strong one threatening to blow some weaker ones up if they don't do as requested ... and the weaker ones doing what was demanded because they objectively figure they can't win and getting blown up is not at all beneficial for an individual). ...But they actually managed to convince a substantial number of their species that an unified empire composed of xuhrl-njok is something they would all individually gain from? Oh dear. 
(I vaguely recall the spryne-part meaning "nation" ... and them sometimes using it interchangeably with individual because each one is out for oneself only anyway.)

...Speaking of which, I can't exactly imagine niin making a nation, either. I figure they wouldn't simply be able to care about being a people long enough, let alone bother with making a nation with borders and rulers and such rather than just settling down wherever seemed convenient, only to wander off again when something more interesting is on the horizon. 

And hmm... Yeah. You haven't said there are beasts as great as those of the Malith Jungle in the west ... but you hadn't said there weren't, either, and there are couple of creatures that are big and fearsome enough in the north, too, including in Rodoria. Some species of powerful bovine-kin (such as used to be here until - surprise - humans hunted them to extinction ... actually, all over the world there used to be massive beasts that humans eradicated) or similar alone would explain why creatures like del-korm showed up... I think currently the main issue with del-korm being from the south (no conflicts with locals provided) would be climate. (Arctic del-korm variant in southern Balazth? Erm...) Could a large island off of northwestern Kirirak work? Del-korm have been placed on an island before. 
(ASTA's character was/is somewhat of an outcast, as I've understood, which in part explains how he ended up so far... And for the matter, del-korm *can* live quite long if they don't get killed ... not sure how long exactly - he can specify -, but well over a century, if not a couple of centuries.)