Note: I was on holidays so just recently did return and now have worked through this thread - I love it that finally something is happening on BT. Now I would like to add one data point:
Regarding contacting IVF diplomatically after their secession:
They should nonetheless try. They might have been surprised. Considering the strategic importance of being proved wrong, I'd have figured it'd be worth a try. It would also be wrong to assume that all realms of that bloc are viewed the same way.
My character is duke of Grehk in Riombara and at the time IVF did seceed was seriously considering (because of being not very much in favor of fighting Enweil in general) to ask Enweil nicely to be allowed to attack IVF. The reason being that he preceives its leader as being completely and rabidly anti-Riombara, far more than any other Enweilian noble. Add to that the overall history and no, I very much doubt that any character in Riombara would consider allying with IVF, even if only to jointly attack Enweil. Aye, strategically stupid (at first glance) but sound reasoning nonetheless. Cheers!
