I received a fairly mundane notification - one of my dwarves had inherited a barony from some relative who died. However, the full implications of this did not occur to me until months later. The dwarven caravan did not arrive that year, which was naturually worrying. I wondered if the goblins had taken the capitol. Peaking at the civ screen, I found that the humans had declared war. While this was worrying and confusing (they had traded with me just fine a few months ago) it did not compare to the realization that my home civ was ALSO at war with me. Now I had done nothing to antagonize them, but I began to wonder about that baron. To my horror, I found that one of the werepanthers living in the wall was the heir. It seems that having the leader of another dwarf site in your civ turn hostile every month somehow sets the entire civ as hostile. While this didn't cause a loyalty cascade, I'm now in rather hot water. The dwarves and for some reason the humans are at war with us. Roleplay wise I can only interpret this as the baroness, fed up with her imprisonment, sending word to the capitol through secret letters from cracks in the wall or something, and using her leverage as baroness to get them to send an army to break her out.
I made contact with other dwarf and human sites to at least establish trade, and sold these dwarves a perfect gem for everything they had, but unfortunately found that the diplomat would not leave the edge of the map until they had conducted a meeting with the baron. One slaughtered diplomat later, after a botched meeting, and I'm now on some political thin ice. I don't think the new dwarves will declare war over this one incident, however.
My main concern is that the mountainhome might send armies of dwarves against me. Does anyone know if a dwarf civ can send sieges against a "rogue" player fort like this?