@zo3bi - The AI-controlled Northern Dunedain faction is trying to unite a successor kingdom and it's crashing. You will need to surrender_regions them to kill them and continue the campaign.
@Dardo21 - I can lessen the negative relations they get with the 'good' factions in Eriador when they accept a ring, but I suspect they will still conquer them when neutral. The EL AI seems to be very aggressive and the dwarf factions in general are a lot more effective than other AI factions.