Nowaru

In Asvald, there are barbarian raids, so it's worse than Darnia.

Firstly, it's most likely only in the border areas (it's hard to imagine barbarians raiding deep underground). Secondly, this could be an additional incentive for the development of this people, so if you're not sent to the front lines yourself, everything will be quite good. Even if you are sent, it's not a given that it will be bad – these are dwarves, they're not very bright, what can they do against the military might of the dwarves? ))

And the climate in Darnia is more favorable.

Well, that's true, and the air is fresher. But maybe the dwarves' bodies are used to it and it will be fine in Asvald.